As between the parties, Polycom, Inc. retains title to, and ownership of, all proprietary rights with respect to the software contained within its products. The software is protected by United States copyright laws and international treaty provision.
Contents: Introduction ......... 1–1 SoundStructure Product Family .
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Step 3 - Device Selection ......... . 4–7 Step 4 - Uploading Or Working Offline .
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Processing On The Signals The Polycom HDX Sends To SoundStructure 6–6 Output Channels To The Polycom HDX ......6–7 Signal Routing Inside The Polycom HDX .
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Signal Meters ........... 7–11 Room Gain .
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Controlling The System ......... . 9–46 8 Mics With The Polycom HDX Video Conferencing System ....9–47 SoundStructure Studio Steps .
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 API Troubleshooting ..........10–9 RS-232 Troubleshooting .
Polycom HDX™ video conferencing system for the ultimate in HD voice, video, and content. The Polycom SoundStructure C16, C12, and C8 audio conferencing devices are single rack unit devices that have 16 inputs and 16 outputs, 12 inputs and 12 outputs, or 8 inputs and 8 outputs respectively.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 • SoundStructure devices are configured with Polycom's SoundStructure Studio software, a Windows®-based comprehensive design tool used to create audio configurations that may be created online or offline, uploaded to devices, and retrieved from devices.
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• Chapter 9 provides example applications with SoundStructure products including stereo audio conferencing applications, room combining, and more. • Chapter 10 provides details on the status LEDs on SoundStructure, and troubleshooting information and steps. • Chapter 11 lists the Specifications for the SoundStructure devices including audio performance, power requirements, and more.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 1 - 4...
SoundStructure Product Family There are two product lines in the SoundStructure product family - the SoundStructure C-series designed for audio conferencing applications (the “C” stands for conferencing) and the SoundStructure SR-series designed for commercial sound applications (the “SR” stands for sound reinforcement). While these two product families share a common design philosophy they have audio processing capabilities that are designed for their respective applications.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 the following figure for a SoundStructure device that has N inputs and N outputs. The specific input and output processing will depend on the product family (C-series or SR-series) and is described later in this chapter.
echo cancellation while the SR-series products do not include acoustic echo cancellation. The processing capabilities will be described in the following sections. Input Processing Up to 8th order highpass and lowpass 1st or 2nd order high shelf and low shelf 10-band parametric equalization Acoustic echo cancellation, 20-22kHz 200 msec tail-time, monaural or stereo Automatic gain control: +15 to -15dB...
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The one big audio matrix architecture can be seen in the following figure where a C16 device is OBAM linked to a C12 device which is OBAM linked to a C8 device. The resulting system will have 36x36 inputs and 36 outputs (16+12+8 = 36).
Phantom power is available on all inputs. All outputs have the same processing capability. A single SoundStructure C16, C12, or C8 device supports 16, 12, or 8 microphone or line inputs and 16, 12, or 8 line outputs, respectively. Up to...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Each SoundStructure C-series device may be used with traditional analog microphones, with Polycom's HDX digital microphone arrays information on using the Polycom HDX digital microphone arrays, see Chapter 6.
C-Series Input Processing The input processing on the SoundStructure C-series devices is designed to make it easy to create conferencing solutions either with or without sound reinforcement. Each audio input on a SoundStructure C-series device has the processing shown in the following table. Input Processing Up to 8th order highpass and lowpass 1st or 2nd order high shelf and low shelf...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 analog input signal is digitized and available for processing. The digital signal is processed by five different DSP algorithms: parametric equalization, acoustic echo cancellation, noise cancellation, feedback reduction, and echo suppression (non linear processing).
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Each analog input signal is processed to create three processed versions that can be used in different ways in the matrix. These three different versions of the input signal mean that, at the same time, an output signal to the loudspeakers can use the sound reinforcement processed version of an input signal, an output signal to the video conferencing system can use the conferencing processed version of the input signal, and an output signal to the recording system can use the recording...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 automatic gain control on the sound reinforcement path from increasing the microphone gain and consequently reducing the potential acoustic gain before the onset of feedback. C-Series Sound Reinforcement Input Processing...
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processing on an input signal. This version of the signal has no acoustic echo cancellation processing and will consequently include any acoustic echo signal that may be present at the microphones. UNGATED - Bypass Mic or Line Analog Parametric Acoustic Echo Input Gain Converter...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Recording/Ungated - Sound Reinforcement Finally, the sound reinforcement recording input includes the echo and noise cancellation and optional feedback elimination processing as shown in the following figure. UNGATED - Sound Reinforcement Processing...
The following figure highlights how to interpret the matrix crosspoints in the matrix. Ungated/Recording Conferencing Sound Reinforcement Ungated/Recording Conferencing Sound Reinforcement Inputs Ungated/Recording Conferencing Sound Reinforcement Ungated/Recording Conferencing Sound Reinforcement C-Series Output processing As shown in the following table and figure, each output signal from the matrix can be processed with dynamics processing, either 10-band parametric or 10-, 15-, or 31-band graphic equalization, a fader, and output delay up to 1000 milliseconds.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 C-Series Submix Processing Submixes are outputs from the matrix that can be routed directly back to the input of the matrix as shown in the following figure. As an output of the matrix, any combination of input signals may be mixed together to create the output submix signal.
As shown in the following figure, each submix signal from the matrix can be processed with dynamics processing, parametric equalization, a fader, and up to 1000 milliseconds of delay. Each SoundStructure device has as many submixes as there are inputs. C-Series Acoustic Echo Canceller References In conferencing applications, an acoustic echo canceller removes the remote site's audio that is played in the local room from being picked up by the local...
Chapter 9. An acoustic echo canceller reference can be created from any output signal or any submix signal. For a SoundStructure C16 device this means that there are 32 possible echo canceller references (16 outputs + 16 submixes) that can be defined and selected.
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reinforcement, and broadcasting. The following figure shows an example of using the SoundStructure SR12 to provide additional line level inputs and outputs to a SoundStructure C8 conferencing product. Telco Microphones SoundStructure Playback/Record SR-Series Favorite Content Playback/Record Favorite Content SoundStructure SR12 12:00 am The SoundStructure SR12 can not be used to add additional conferencing microphones to a C series product because there is no acoustic echo...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 particular SoundStructure C-series device, either the next largest C-series device or additional C-series devices must be used to support the number of microphones required. The C-series and SR-series products can be used together and linked to form...
SR-Series Input Processing The input processing on the SoundStructure SR-series devices is designed to make it easy to create commercial sound and sound reinforcement solutions. Each audio input on a SoundStructure SR-series device includes the signal processing path shown in the following table. SR-Series Input Processing Up to 8th order highpass and lowpass 1st or 2nd order high shelf and low shelf...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Each analog input signal has an analog gain stage that is used to adjust the gain of the input signal to the SoundStructure's nominal signal level of 0 dBu. The analog gain stage can provide from -20 to 64 dB of analog gain in 0.5 dB...
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The automixer processing is only applied to the noise cancelled and sound reinforcement signal paths to ensure that there is an 'un'-automixed version of the input signal available for recording/ungated applications SR-Series Input Processing Dynamics Automatic Dynamics Gain Control Processor Router Mic or Line Analog...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 microphone audio to paging zones that are not acoustically coupled to the microphone. This is the default processing for microphone inputs when the automixed version of the signal is selected.
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For additional flexibility in audio applications, there are four different versions of the recording/ungated signal that can be selected through the four-input router shown in the previous processing figures. This selection of which type of recording/ungated signal to choose is performed on an input by input basis within the SoundStructure Studio software as described in Chapter These four ungated versions are described in more detail below: 1.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Recording/Ungated - Noise Cancelled The noise cancelled recording input includes the noise cancellation as shown in the next figure. This path is typically used for recording of microphone audio as it includes all the noise cancellation but not the automatic microphone mixer processing.
represented with different background colors at the matrix crosspoint. The SoundStructure Studio software allows the user to select which version of the input signal processing at the matrix crosspoint. The next figure shows how to interpret the matrix crosspoint view. Ungated/Recording Conferencing Sound Reinforcement...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 SR-Series Output Processing Output from Dynamics Matrix Processing SR-Series Submix Processing The submix processing for the SR-series of products is identical to the processing for the submix processing in the C-series and shown in the following table and figure.
Submix Input from Matrix Telephony Processing Both the C-series and SR-series SoundStructure devices support optional plug-in cards. Currently there are two telephony cards: TEL1, a single-PSTN line, and TEL2, a dual-PSTN line interface card in the form factor shown in the following figure.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The SoundStructure telephony cards have been designed to meet various regional telephony requirements through the selection of a country code from the user interface. For each telephony interface card, the signal processing is listed in the following table and shown in the following figure.
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progress detector that analyzes the telephony input signal and reports if any call progress tones are present (for example, if the telephony line is busy, the phone is ringing, etc.). Telephony Processing To Telco Dynamnics from Matrix Processing Tone Generator From Telco Parametric Delay...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2 - 30...
SoundStructure Design Concepts Before creating designs for the SoundStructure devices, the concepts of physical channels, virtual channels, and virtual channel groups will be introduced. These concepts form the foundation of SoundStructure audio designs. In addition, the concepts of defining control virtual channels and control array virtual channels from the logic input and output pins will be introduced.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 be used and take extra care to ensure that commands are referencing that exact input or output signal. If device identification numbers are changed or different inputs or outputs are used from one design to the next, this requires...
For if there are two devices and the first device is a SoundStructure C16, the first input on the second device becomes physical input 17. This continuation of the sequence of numbers is possible due to the design of the OBAM Link interface.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The OBAM link is bidirectional - data flows in both an upstream and downstream direction meaning that the bus does not need to be looped back to the first device.
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1 through N where N is the number of inputs and outputs on the device (for instance, 16 inputs for a SoundStructure C16 device). 2. The SoundStructure device whose OBAM IN port is connected to the...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Following the connections in the previous figure, as an example of this linking order and how the physical channels are numbered, consider the system of three SoundStructure C16 devices shown in the following figure. In this...
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Device A's inputs and outputs become the first sixteen physical inputs and sixteen outputs on the system, device B's inputs and outputs become the next sixteen physical inputs and next sixteen physical outputs on the system, and device C's inputs and output become the last sixteen physical inputs and sixteen physical outputs on the system.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 finally device B becomes the third device in the link. The result is that the inputs and outputs on device C will become inputs 17-32 and outputs 17-32 on the full system even though device B is physically installed on top of device C.
The first input on the second device will be input 17 (if the first device is a SoundStructure C16). In the next section, the concept of physical channels will be extended as the...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Virtual Channels A virtual channel can be thought of as a layer that is wrapped around one or more physical channels. A virtual channel can represent either an individual physical channel or it can represent a collection of strongly associated physical channels, such as a stereo pair of signals as shown in the following figure.
example, mutes or changes volume) the SoundStructure devices through the virtual channel names, not the underlying physical input and output that a particular audio signal is connected to. For instance, if a virtual channel were named “Podium mic” then the control system code would control this channel by sending commands to “Podium mic”.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Using SoundStructure virtual channels is the only way to configure and control the underlying physical channels with third-party control systems. The physical input and output channel numbering described in section 3.1 Physical Channels virtual channel knows which physical channel(s) it refers to.
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group “Mics” has been created, it is possible to configure and control all the microphones at the same time by operating on the “Mics” virtual channel group. It is possible to have multiple virtual channel groups that include the same virtual channels.
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1, the podium mic on input 2, the table mics 1-8 on inputs 3-10, a stereo VCR is connected to inputs 11 and 12 and a Polycom HDX video codec is connected over the digital ConferenceLink interface.
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Virtual channel definitions could be defined as shown in the following figure. Physical Channel Virtual Channel Inputs “Wireless mic” “Podium mic” “Table mic 1” “Table mic 2” “Table mic 3” “Table mic 4” “Table mic 5” “Table mic 6” “Table mic 7” “Table mic 8”...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Virtual Channel Group Summary Virtual channel groups are an easy way to create groups of signals that may be controlled together by sending an API command to the virtual channel group name.
Physical Logic Pins The physical logic pins and their labeling is shown in the following figure. Pin 13 Pin 25 Pin 13 REMOTE CONTROL 1 Pin 25 REMOTE CONTROL 2 The logic inputs and logic outputs have physical inputs and outputs 1 - 11 on Remote Control 1 connector and 12 - 22 on Remote Control 2 connector on each SoundStructure device.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 When multiple devices are OBAM linked as shown in the next figure, the logic inputs and outputs on the first device will be numbered 1 - 22 and the logic inputs and outputs on the second device (device B) will be numbered 23 - 44, and so on.
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Logic Inputs All digital logic inputs (logic inputs 1 - 22) operate as contact closures and may either be connected to ground (closed) or not connected to ground (open). The logic input circuitry is shown in the following figure. SoundStructure Logic Input Logic Status Analog Gain Input...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Logic Outputs All logic outputs are configured as open-collector circuits and may be used with external voltage sources. The maximum voltage that should be used with the logic outputs is 60 V with a maximum current of 500 mA.
SoundStructure Design Concepts Logic pins can be defined via the command line interface from SoundStructure Studio or a control terminal with the following syntax to define a logic input on logic input pin 1: vcdef “Logic Input Example” control digital_gpio_in 1 which will return the acknowledgement vcdef "Logic Input Example"...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The value of the digital control array is the binary sum of the individual logic pins. For example if a control array virtual channel is defined with digital output pins 3, 2, and 1, then the value of the control array channel will be in the range of 0 to 7 with physical logic output pin 3 as the most significant bit and physical logic output pin 1 as the least significant bit.
1 is the only physical channel that can be specified since there is only one physical IR receiver channel. Once a command from the Polycom HDX IR transmitter, a command acknowledgement of the form: val ir_key_press “IR Input” 58 will be generated by the SoundStructure device when a key that corresponds to code 58 is pressed on the IR remote transmitter.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 3 - 24...
Creating Designs with SoundStructure Studio SoundStructure Studio is the software environment for creating, managing, and documenting SoundStructure designs. SoundStructure Studio communicates with SoundStructure devices over a communication link (RS-232 or Ethernet) using the SoundStructure API commands. For information on the SoundStructure command protocol, see Appendix A - SoundStructure Command Protocol Reference Guide.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 • • • These steps are described in more detail in the following section. 4 - 2 Follow the on-screen steps to specify the output signals Select the SoundStructure devices to be used for the design...
PC, it may be installed from the CD that was included with the product. More recent versions of SoundStructure Studio may also be available on the Polycom website - please check the Polycom website before installing the SoundStructure Studio version that is on the CD-ROM.
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SoundStructure Designs. The choices for Hybrids/Codecs include the Polycom HDX video codec, the Polycom VSX series, and a generic mono or stereo video codec. When the Polycom HDX video codec is selected, it is assumed that the Polycom HDX connects to the SoundStructure device over the Conference Link2 interface. To...
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(a dot with two waves on both sides). When a Polycom HDX video codec is selected, there are multiple audio channels that are created automatically and usable independently in the SoundStructure matrix. See Chapter 6 - Connecting over CLink2 for additional information on the audio channels and the processing that is available on these channels.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Step 2 - Output Signals In step 2 of the design process, the outputs from the system are specified in the same manner that inputs were created. A sample collection of outputs is shown in the following figure.
8 microphones, 1 wireless microphone, and the stereo program audio and the line outputs are used by the stereo amplifier and the mono recorder. The Polycom HDX video codec does not require any analog inputs and outputs because the signals are transferred over the digital Conference Link2 interface.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Step 4 - Uploading Or Working Offline In step 4, the decision is made to either work offline or to work online. When working online, a set of devices can be selected to upload the settings to via the Ethernet or RS-232 interfaces.
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Creating Designs with SoundStructure Studio Once the finish button is clicked, the SoundStructure Studio software will create the entire design file including defining all the virtual channels and virtual channel groups such as those shown the following figure. The next chapter will describe how to customize the SoundStructure device settings.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Online vs. Offline SoundStructure Studio has been designed to fully operate in either online or offline modes. Online operation means that SoundStructure Studio is communicating with one or more SoundStructure devices and is sending commands to the devices and receiving command acknowledgements from the devices.
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In this example the virtual channel group “Mics” was muted and the console shows the command in blue and the acknowledgements generated in green. When SoundStructure Studio is working offline, the prefix [Offline]: is shown in the console as a reminder that commands are not being sent to actual devices.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 4 - 12...
Customizing SoundStructure Designs Once a SoundStructure project file has been created as described in the previ- ous chapter, the SoundStructure Studio software can be used to adjust and customize the design. This section provides in-depth instructions on how to customize the settings by using the Wiring, Channels, Matrix, Telephony, and Automixer pages.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 physical channel. If it is necessary to change the wiring from the default wiring, the virtual wiring may be changed by clicking and dragging signals from their current input or output to a new input or output as shown in the following figure. In this example the “Recording”...
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When a virtual channel is moved, SoundStructure Studio redefines the virtual channel to use the new physical inputs or outputs that are specified. Moving a virtual channel does not create any visible changes in the matrix or channels page since SoundStructure Studio operates at the level of the virtual channel and not the physical channels.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Edit Devices When working offline, the Wiring Page includes an “Edit Devices” control for changing the underlying SoundStructure equipment that was selected during the design process as shown in the following figure.
Customizing SoundStructure Designs fit into the next smaller SoundStructure device requires removing audio chan- nels from the “Edit Channels” control. Channels Page The channels page is the primary area for customizing the signal gains and processing for the input, output, and submix signals. Regardless of the number of SoundStructure devices used in a design, there is only one channels page and that page shows all the virtual channels for the entire design.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 figures for examples of the different user controls. It is possible to change which types of virtual channels are viewed by enabling or disabling groups, inputs, outputs, and submixes with the controls on the top of the Channels page as shown in the following figure.
button as shown in the following figure. Any of the settings for virtual channels can be adjusted by either adjusting the virtual channels individually or by adjusting the virtual channel group settings. Editing Virtual Channels To add or delete additional virtual channels, click the “Edit Channels” button on the Channels page as highlighted in the following figure.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Channels page and there will be default gain settings for the devices and default signal routing will be created for the matrix based on the type of signal added. If virtual channels are deleted, they will be removed from the Channels page and their matrix signal routings will also be removed.
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Customizing SoundStructure Designs Collapse buttons respectively. To create additional virtual channel groups, click the Edit Groups button on the Channels page to cause the Edit Groups screen to appear as shown in the following figure. All existing virtual channel groups will appear on the right of the screen.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Once a virtual channel group has been defined, virtual channels may be added to the virtual channel group by selecting the desired virtual channels. More than one virtual channel may be selected by left clicking on the first channel and then shift-clicking on subsequent virtual channels.
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Customizing SoundStructure Designs Any commands that are sent to configure the virtual channel group “Zone 1 Mics” will in turn be sent to the members of the virtual channel group. For example if a mute command is sent to “Zone 1 Mics” then “Table Mic 1”, “Table Mic 2”, and “Table Mic 3”...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 there are no dashed lines around the gain for the “Zone 1 Mics” group. Changing virtual channel group settings will change all the settings for the virtual channels that are part of the virtual channel group and generate command acknowledgements for the virtual channel group and its virtual channels members.
Customizing SoundStructure Designs Input Signal Meters All these input channels have meters that will show the signal activity. The meters may be enabled from the Tools menu or from the lower right hand corner of the screen. To enable the signal meters from the Tools menu, select the menu item Tools and then Options.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 to the SoundStructure device, however the meters will be most responsive over the Ethernet interface. If meters are viewed over the RS-232 interface, it is recommended that the highest data rate of 115,200 baud be used to minimize any lag between registering for meters and having the meter information dis- played on the screen.
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meter will show less signal activity. Since the level_pre meter position is before any processing has been applied to the signal, even if the signal is muted within the SoundStructure device, the level_pre input meter will show any signal activity on that input. The level_post meter is after any processing as shown in the following figure.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 adjustments. Line Input level_post Line input channels, such as program audio or audio from video codecs that are connected via analog inputs and outputs, will be metered at the Record- ing/Ungated output shown in the following figure.
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For more information on the processing available for the Clink2 channels, see Chapter 6 Connecting To Conference Link devices. HDX Program Audio In Video Call In Inputs from Polycom HDX over CLINK2 PSTN In UI Audio In Dynamnics Parametric Delay...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Input Channel Controls This section discusses the input controls in the order that they appear on the channels page. The input channel settings are shown in the following figure in both a collapsed view and with the different areas expanded to show the addi- tional controls.
Customizing SoundStructure Designs collapsed. Analog Signal Gain SoundStructure devices have a continuous analog input gain stage that oper- ates on the analog input signal and has a range of -20 dB to +64 dB with 0.5 dB gain increments. Values are rounded to the nearest 0.5 dB. This continuous gain range is different from the gain Vortex products uses because the Vortex microphone inputs have a mic/line switch that adds 33 dB of gain to a Vortex input signal.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Since there is only one large input range on SoundStructure devices, it is easier to see how much gain is required for each microphone input. Gain settings are adjusted by moving the slider or typing the input value into the user control.
Customizing SoundStructure Designs button which is labeled Phan. Ungated Type The ungated type user control refers to which signal path to use for the ungated (or un-automixed) processing path. The decision of whether to use the ungated version of the input channel processing is made at the matrix cros- spoint as shown in the following figure where the gated type None is highlighted.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 input basis. As described in Chapter 2, there are four different types of ungated signal pro- cessing paths that may be selected for each input. The different signal processing paths for the four ungated signal types are summarized in the fol- lowing table.
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where a program audio source can be processed with parametric equalization, automatic gain control, dynamics processing, fader, delay, and input mute. Favorite Content Parametric Equalization The Sound Reinforcement path is selected by default for microphone audio because that processing path includes the full echo and noise cancellation, but does not include the non-linear processing associated with the acoustic echo canceller to avoid the application of any echo canceller suppression (or duck- ing) to the signal.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 UNGATED - Bypass UNGATED - Bypass Mic or Line Analog Parametric Acoustic Echo Input Gain Converter Equalization Cancellation UNGATED - Line Input Processing UNGATED - Line Input Processing Mic or Line...
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following figure. UNGATED - Sound Reinforcement Processing Mic or Line Parametric Acoustic Echo Analog Input Gain Converter Equalization Cancellation Cancellation Parametric Acoustic Echo Equalization Cancellation The low delay type corresponds to a processing path that completely bypasses the processing of the AEC and noise cancellation. Because these processing blocks are not in the signal path, the signal has lower latency.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 sound reinforcement paths. UNGATED - Sound Reinforcement Processing Mic or Line Analog Parametric Acoustic Echo Input Gain Converter Equalization Cancellation Parametric Equalization C-Series Sound Reinforcement Input Processing Mic or Line...
Customizing SoundStructure Designs Bypass ungated signal type is selected as shown in the following figure. Trim The trim command is used with stereo virtual channels to provide additional gain or attenuation in the analog domain to the underlying left or right physi- cal channels in case the incoming signal levels need to be adjusted separately.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 gain of 64 dB will be added in the digital domain. Equalization The equalization processing that is available for each input consists of dedicated • • • • •...
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Customizing SoundStructure Designs enabled. To enable a filter, click the button next to the filter, and then adjust the param- eters for the filter block as shown in the following figure. The cut off frequency of the Low Pass and High Pass filters can be adjusted between 0 Hz and 20,000 Hz, the order can be adjusted from 2 to 8 , and...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 • • Parametric filters emphasize or de-emphasize the center frequency with a gain and bandwidth setting. The user can specify the bandwidth (in octaves), center frequency (in Hz), and gain (from 0 to 20 dB).
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figure. There is a safe mode attenuation that defines the amount of attenuation that can be applied to the signal if the feedback eliminator filters are all engaged and there is still feedback. The safe mode attenuation can be set from 0 to 20 dB of attenuation and has a default value is 3 dB.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 selecting the Snd Reinforcement option of the gated/automixed as shown in the following figure. Selecting the Snd Reinforcement option will ensure that the proper input processing path is selected for routing microphones to loudspeakers.
group. References can be selected from any output signal or from any submix signal. A reference can be either a mono virtual channel or a stereo virtual channel. If only a single mono virtual channel reference is specified, the system is operat- ing as a monaural echo canceller.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 dynamics processing, fader, delay, and mute. The acoustic echo canceller is also in this signal path but should not be enabled for non-microphone audio sources. UNGATED - Conferencing Processing...
Customizing SoundStructure Designs nals so that the average signal level is close to the SoundStructure nominal signal level of 0 dBu. The AGC processing can be used on any input signal. AGC is typically used on microphone input signals to compensate for local talkers that are different distances from their microphones or telephone input signals to compensate for varying telephone levels.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 input signals. SoundStructure devices include the following styles of look-ahead dynamics processing. • • • • • The SoundStructure Studio user interface for adjusting the dynamics settings are shown in the following figure.
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Compressors And Limiters The peak limiter monitors the peak signal magnitude and compares it to a threshold. If the peak surpasses the threshold, the peak limiter immediately attenuates the signal with a very fast attack to bring the peak level below the threshold.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Decreasing the attack time will allow the compressor/limiter to work more aggressively but may also introduce audio artifacts. Limiters perform just like compressors, but are typically set with higher com- pression ratios (10:1 or more) to further limit the dynamic range of signals levels above the threshold.
Customizing SoundStructure Designs input signal level and the gate threshold. For example, if the gate ratio is 10:1 and the input signal level is 6 dB below the gate threshold, the gate applies 60 dB of attenuation. The gate attack is the amount of time it takes the gate to ramp the gain to the target gain once the input signal level surpasses the gate threshold.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 ing the Remove Channels button. There are two styles of automixer groups – gating and gain-sharing. The con- trols for these two styles of groups will be described next.
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Customizing SoundStructure Designs Camera Activity Time Camera Activity Time specifies how long the microphone must be considered active before a camera indicator is set. The camera indicator is a status mes- sage that can be used with an external control system to indicate that a particular microphone is active.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 have to be eligible to be considered active. Higher settings will make the chan- nel less sensitive - harder to turn the microphone on, while lower settings make it more sensitive - easier to turn the microphone on.
Gain Sharing Automixer Parameters Slope The Slope parameter determines the selectivity of how the gain is adjusted on the gain-sharing automixer by setting a multiplier on the gain that is applied to active microphones. The difference in levels detected by the automatic microphone on the active microphones will be scaled by the slope parameter to create a gain for the automixer.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 in the digital domain. The fader control is shown in the following figure. A maximum and minimum gain range can be specified for the input faders to make it possible to limit user gain control by moving the triangles associated the gain slider.
Customizing SoundStructure Designs Signal Generator Each SoundStructure device can have a single signal generator defined can generate white noise, pink noise, a sine wave, and a sine sweep. By default, each project will have a signal generator with pink noise at a level of -30dB added to the project.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Output Signals This section describes the user interface for configuring output signals. Every output signal has the processing capabilities described in the following section. All output signals have signal meters as shown in the following figure. To enable the signal meters, select the menu item Tools and then Options.
Output Processing Parametric Output from Dynamics or Graphic Matrix Processing Equalization Dynamics The output dynamics processing available on the outputs is the same as the input dynamics processing and is described previously in the Dynamics Pro- cessing section of Input Signals in this chapter. Equalization The output equalization includes a dedicated Low Pass, High Pass, Low Shelf, and High Shelf filter.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Output EQ Type parameter as shown in the following figure. The center frequencies of a graphic equalizer are specified in the ISO 266 stan- dard. These are similar to the standard set of resistor values, but the series is chosen to map well to fractional octave and decade intervals between center frequencies.
following table. These band edges are exactly between the center frequencies. At the band edges, the gain of the equalizer band is half the gain (in dB) at the center fre- quency. Adjacent bands in the graphic equalizer bleed over into each other and affect each others' total gain which can increase the amount of time a user must spend adjusting the equalizer to arrive at a desired frequency response.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Submix Signals This section describes the processing that is available for each submix channel. Submixes may be defined as mono virtual channels or stereo virtual channels. When the submix is a stereo virtual channel, the processing is applied equally to both the left and the right physical channels that define the stereo virtual channel.
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• High Pass, • Low Shelf, • High Shelf, and • 10 parametric equalizers as shown in the following figure. To enable a filter, click the check box next to the filter. This will make the filter the active filter and allow the parameters to be changed as shown next. The cut off frequency can be adjusted between 0 Hz and 20,000 Hz, the order can be adjusted from 2 to 8...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Allpass filters do not modify the gain of the signal, but change the phase. For a second order allpass filter, the phase shift is 0 degrees at 0 Hz, 360 degrees at high frequencies, and 180 degrees at the center frequency.
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2. When a mono input signal is mapped to a stereo output signal with a gain of 0 dB, the mono input is mapped to both the left and the right physical output channels with an attenuation of 3 dB. Each group of virtual channels has a heading associated with it - the virtual channel group name - that allows the group to be collapsed or expanded.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The collapsed view simplifies the configuration and setup of the system as there are fewer crosspoints to manage. Adjusting Crosspoints Any matrix crosspoint may be adjusted over the range of +20 dB to -100 dB in 0.1 dB increments.
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Customizing SoundStructure Designs and mute status may be adjusted on the matrix page or on the channels page. To edit a crosspoint, double left click on the crosspoint to bring up the Edit Crosspoint control. Once the edit crosspoint control has been opened, the cros- spoint control will always go to its last position.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 adjustment directly. Mute The matrix crosspoint may be muted by clicking the Mute button. Muted cros- spoints will be shown in the matrix as grayed out values if the Hide Muted Matrix Crosspoints option is not enabled in the Options...
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Customizing SoundStructure Designs cessing should be selected. To select the conferencing version of the input processing, select the Gated and Conferencing as shown in the following figure. The crosspoint background will turn blue to indicate the conferencing version of the input processing is 5 - 57...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 selected. To select the ungated/recording version of the crosspoint, select the None gated version of the input processing. The background of the crosspoint will turn white to indicate that the ungated/recording version of the input process- ing is selected.
shown in the following figure. Balance The balance control allows the designer to adjust how a stereo input signal is mapped to a stereo output signal. A value of 0 means that the left input chan- nel is sent to the left output channel and the right input channel is sent to the right output channel.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Ungated/Recording Conferencing Sound Reinforcement Ungated/Recording Conferencing Sound Reinforcement Inputs Ungated/Recording Conferencing Sound Reinforcement Ungated/Recording Conferencing Sound Reinforcement Telephony Channels To use a telephone interface, either the SoundStructure TEL1 or TEL2 must be included in the design and installed in the SoundStructure device.
Customizing SoundStructure Designs described in this section. Input Gain The telephone input gain has a range from -20 to +20 dB for adjusting the gain in the analog domain and has a default gain of 0 dB. The gain required will depend on the signal levels received from the telephone line.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 analog input gain adjustment on the telephone input virtual channel. The input channel level_post meter corresponds to the meter next to the input fader control. The output channel level_post meter corresponds to the meter next to the output gain adjust.
meter and the text box next to the AGC meter. The range of the AGC can be adjusted by expanding the AGC control and adjusting the maximum and minimum gains. By default the maximum and minimum gain are set to 6 and -6 respectively on microphone and telephony signals.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 figured to have different equalization. To enable a filter, click the check box next to the filter. This will make the filter the active filter and allow the parameters to be changed as shown next.
Fader The fader control enables the user to add gain or attenuate the telephone signal from +20 dB to -100 dB with a resolution of 0.1 dB. This gain is applied in the digital domain. A maximum and minimum gain range can be specified for the faders to limit the user gain control.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The telephony channel controls are shown in the following figure. Phone Connect The telephone interface may be taken off hook by pressing the phone button on the controls page. Once the telephone is off hook, digits may be dialed by pressing the keys on the keypad.
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Customizing SoundStructure Designs Ring Tone Ring tone enabled will cause the SoundStructure device to play ring tones into the local room when the telephone line rings. If Ring Tone is disabled no ring tone will be heard although a phone_ring status message will be generated by the SoundStructure device when the phone is ringing.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Line Voltage and Loop Current The line voltage and loop current are active whenever the Poll Telephony Information is enabled at the top of the user control. The line voltage and loop current allow for diagnostics of the telephone line.
Polycom devices, only one Polycom HDX video conferencing system may be connected to a SoundStruc- ture device. The Polycom HDX video conferencing system may only be connected to a SoundStructure C-series product. Physical Connections...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The rear-panel of the SoundStructure product with the Conference Link2 con- nections highlighted is shown in the following figure. Polycom HDX Integration The SoundStructure devices may be connected to the Polycom HDX video conferencing system using the supplied Conference Link2 cable as shown in the next figure.
CLink2 Designing With The Polycom HDX Video Codec Within SoundStructure Studio, the Polycom HDX video system may be selected from the video codec selection category and then clicking Add to add the codec to the list of inputs as shown in the following figure.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Input Channels From The Polycom HDX Once the Polycom HDX video system is selected, four SoundStructure input virtual channels are automatically added to the input channels as shown in the next figure.
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The input channels from the Polycom HDX are described in the following table. HDX Signal to SoundStructure HDX Program Audio In HDX PSTN In HDX UI Audio In HDX Video Call In Connecting Over Conference Link2 Description A stereo virtual channel that contains a mix of all non-microphone inputs to the Polycom HDX.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Processing On The Signals The Polycom HDX Sends To SoundStructure Each of the signals that the Polycom HDX video system sends to the Sound- Structure device have processing that can be applied as shown in the following figure.
Output Channels To The Polycom HDX SoundStructure Studio creates several output virtual channels that are sent to the Polycom HDX system as shown in the following figure. The output channels sent to the Polycom HDX are described in the following table. Signal from SoundStructure...
Processing Dynamics Processing All the signals that are sent to the Polycom HDX system have signal level meters that are displayed on the Channels page. Signal Routing Inside The Polycom HDX The Polycom HDX system receives the SoundStructure output signals and internal to the HDX mixes the signals it needs to create the transmit signals to the HDX PSTN interface and HDX Video interface.
If the mute state changes on the SoundStructure system, the Polycom HDX does not receive the mute event from the SoundStructure device. Only when mute commands are sent to the Polycom HDX via a control system or infra-red remote will the mute event be automatically transmitted to the SoundStruc- ture device.
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“Mics” 0 depending on whether the HDX system is being muted or unmuted. No audio paths are muted inside the Polycom HDX when an HDX, that is connected to a SoundStructure device over CLink2 interface, receives a mute command.
The fader command executed on the SoundStructure device is: set fader “Amplifier” x where x is the HDX volume level minus 30. At the maximum volume setting for the Polycom HDX (50), this will cause the SoundStructure to execute the command set fader “Amplifier” 20 This will set the fader control for the virtual channel “Amplifier”...
SoundStructure system will not be recognized by the HDX. This means that while the user adjusts volume on the Polycom HDX, it will appear as the volume continues to change on the Polycom HDX UI although a volume limit may have already been reached within the SoundStructure system which would prevent the system from getting any louder in the room.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The following table shows the number of analog inputs that are available based on the number of microphone arrays that are used in a system. As an example, a SoundStructure C16 supports 16 analog inputs. When used with two microphone arrays, 10 analog inputs are still available for use with other analog inputs including microphones, program audio, etc.
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PIN 7: CTS PIN 8: RTS REMOTE CONTROL 1 RS-232 REMOTE CONTROL 2 [0] HDX [1] SoundStructure [2] HDX Mic (f/w 24) [3] HDX Mic (f/w 24) [4] HDX Mic (f/w 24) [5] HDX Mic (f/w 24) SoundStructure C16 6 - 15...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Because microphone arrays may be shipped with a firmware version that may be earlier than version 24, the firmware should be updated once to revision 24 by connecting the microphones directly to the right CLink2 port (the port clos- est to the OBAM interface) on SoundStructure device for 30 seconds.
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Connecting Over Conference Link2 The first step of the design process is to select the input signals as shown in the following figure. Notice that for each HDX ceiling microphone array that is added, there are three mono microphones with names that include A, B, and C that are added to the project.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 In the third step, the equipment is selected. In this case a C12 is required and will have three additional analog inputs available that can be used once the system has been designed.
Assigning Digital Microphone Array Channels To Physical Inputs When HDX digital microphone arrays are used within SoundStructure Studio, SoundStructure Studio assigns the processing for each digital microphone input from a physical analog input. SoundStructure Studio will reserve processing by starting with the last analog input channel and working towards the first analog input.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 In this example, up to six analog inputs can be used (three analog inputs are presently in use) in addition to the two HDX ceiling microphones. The digital microphone array elements can be moved on the wiring page to different physical inputs if desired by clicking and dragging the microphone to move it to a different physical input.
PIN 2: TXD PIN 3: RXD PIN 5: GROUND PIN 7: CTS PIN 8: RTS RS-232 HDX Mic 1 OBAM Connecting Over Conference Link2 SoundStructure C16 POLYCOM POLYCOM HDX Mic 3 HDX Mic 4 HDX Mic 2 POLYCOM POLYCOM 6 - 21...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The orientation of the microphone does not affect the sequential numbering as shown in the following figure. When an HDX system is also connected over the CLink2 interface and the...
There are several installation options available depending on whether tabletop or ceiling microphones are being used. The following figure shows typical wiring options using the Polycom SKUs highlighted with the dashed boxes for tabletop microphones and ceiling microphone arrays. These SKU’s include the cables that are shown within the dashed boxes and are summarized in the table below.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The digital tabletop microphone arrays are connected via Walta terminated cables and then the last cable is terminated into the SoundStructure via the Walta to RJ45 interface cable. The digital ceiling microphone arrays are connected via RJ45 terminated cables and may be connected directly to the rear-panel of the SoundStructure.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A summary of the cables is shown in the following table. The pin outs for the RJ45 terminated cables 22457-24008-001 and 2457-24009-001 are shown in Chapter 11 - Specifications. Both of these cables have the same pin out and differ only in length.
Installing SoundStructure Devices This chapter describes how to take the SoundStructure designs created in Chapters 4 and 5 and upload and confirm that the system is fully functional. Once the SoundStructure design has been created, the next steps are to match the physical wiring of the system, upload the settings, make final adjustments to the system, and save the settings to a preset.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Wiring The Devices One of the most important steps when working with SoundStructure devices is to ensure the physical cabling (for instance what’s plugged into input 3) of the system exactly matches how the virtual channels are defined.
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input 9 and the VSX8000 input is connected to input 10. On the outputs, the amplifier output is connected to physical output 2 and the VSX8000 output channel is connected to physical output 1. If the system were wired incorrectly and the VSX8000 Out channel and Ampli- fier channel were reversed due to a physical wiring error, then the signals that were routed to the VSX8000 output channel would now be physically con- nected to the amplifier.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 There is a wiring report that can be created by clicking the Save Report button on the wiring page as shown in the following figure. The wiring report for this system is shown next.
Installing SoundStructure Devices Uploading A Configuration File Configuration files are uploaded to a SoundStructure device or downloaded from a SoundStructure device by using the SoundStructure Studio software. To upload a configuration file to the SoundStructure devices, first open the SoundStructure Studio design file and then select the Connect menu and select Connect to Devices as shown in the following figure.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 dio. If the Serial control is checked, the system will also search for devices over the RS-232 interface as shown in the following figure. Any discovered devices will be displayed and the baud-rate and flow control settings required to connect to those devices will be displayed.
If the device is running a configuration file that had previously been uploaded, the output channels will be muted while the new configuration is uploaded. The audio will be unmuted after the upload of the configuration file has been completed. Once the file has been uploaded, the settings are stored in the non-volatile memory of the device.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Once connected to a device as described in the previous sections, click on the System name - SoundStructure System in this example - to navigate to the firmware update page shown in the following figure.
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Installing SoundStructure Devices Select the file by double clicking on the desired file name. Once the file has been selected, the firmware update page will appear as in the following figure. Click on the update button to begin the firmware transfer to the device. A window will appear to confirm that the firmware file should be sent to the selected device.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Configuring The Signal Gains Once the SoundStructure device settings are synchronized with SoundStruc- ture Studio, either by uploading or downloading a configuration file, the next step is to ensure the input signals have the proper analog gain to get to the 0 dBu nominal signal level of the SoundStructure devices.
sense, the meter segment label represents the minimum signal level required to light the meter segment. The clip indicator at +20 will illuminate when the signal exceeds +20dB. Signal Meters The meters on the SoundStructure devices show a VU average signal level with a peak meter overlaid on the VU meter.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 For example, a common tabletop microphone has a sensitivity of -27.5 dBV/Pa. which translates to an input gain of 48dB. Room Gain Room gain meters are used to measure the relative level of the remote audio that is present at the input to the AEC with the level of the echo that is present at the microphone.
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The following figure shows different room gain measurements that may be found in a typical room. Room gain is considered good if it is negative, mean- ing that the echo picked up by the microphone is less than the level that is output to the amplifier.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 When two mono AEC references are used, or a stereo virtual channel is used as the reference as shown in the following figure, there are two room gain indi- cators, one for each reference.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Output Signal Levels Output signals from the SoundStructure device are connected to various other devices including audio amplifiers, recorders, and video codecs. For best per- formance, the output signal levels of the SoundStructure devices should match the expected signal levels of the next device that is attached.
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Setting Amplifier Levels It is important to set the proper level of the audio amplifier in the room. This can be done with the following steps using the SoundStructure noise generator and an SPL meter. If there are no SPL meters than can be used, the ears of the local participants can be used to help set a comfortable level in the room.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2. Set the analog output gain on the amplifier output channel to be either +4, 3. Turn down the audio amplifier to the lowest possible volume setting 4. On the channels page unmute the signal generator and ensure the gain is...
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5. Set the output fader from the SoundStructure device to 0 as shown in the next figure and unmute the signal generator to the loudspeaker output. Pink noise may be heard in the room depending on the amplifier volume settings. 6.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 be performed by adjusting the level of the fader on the “Amplifier” channel within the SoundStructure device. Chapter 9 provides examples of using the “Amplifier” channel for volume control.
Restore Preset Power-On Full Preset SoundStructure full presets operate in a similar fashion to Polycom’s Vortex products where there is a “power on” preset that must be selected for the design when the device powers up. When creating a new design, the last step of the SoundStructure design process will save the settings to a preset called “Power-On”...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Preset Names When presets are stored, the preset name may be customized to any arbitrary string of up to 256 bytes in length. When naming presets, keep in mind the preset name is used in the command syntax to invoke the execution of the pre- set.
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The preset page shows the presets and also the preset contents to make it pos- sible to determine the settings that are in each preset. The column headings may be selected to sort the preset based on the values in the column. Changing sort order does not change the order of execution if the entries are in the preset.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Column Header Col Channel Index Value Saving a preset to the SoundStructure system will cause the preset to be writ- ten into the non-volatile memory of the SoundStructure device. When online, the settings will be transferred to the SoundStructure device and stored in the non-volatile memory.
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Installing SoundStructure Devices • Creating new blank partial presets Partial presets consist of a sequence of commands that will be executed in the order they appear in the partial preset. If an entry is removed from a full pre- set, the full preset becomes a partial preset. If there is only one full preset, entries in the preset may not be deleted or added to ensure there is at least one full preset.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 New partial presets may be created by selecting ‘New Partial’ as shown in the following figure. The next step is to enter a name for the partial preset as shown in the following figure.
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Once the empty partial preset has been created, the next step is to add com- mands to the partial preset by clicking the ‘+’ control. This will add an empty line to the partial preset, and allow the designer to select the parameter to adjust with this line as shown in the following figure.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Once entries have been moved, select “Save Selected” to save the new execu- tion order. Running Presets Both full and partial presets may be executed when in SoundStructure Studio by left clicking the preset to execute and then clicking Run Preset.
Full preset execution does not generate any command acknowledgements from the SoundStructure system. If specific parameters are required after a preset has been executed, the values for the parameters should be queried after a preset has executed. The outputs of the system are muted during the execution of a full preset. The outputs are unmuted after the preset has executed.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 7 - 30...
Network Management This chapter describes the network and control aspects of SoundStructure sys- tems including managing the device over IP and configuring the RS-232 port. Connecting To The Device SoundStructure devices have a LAN interface and RS-232 port that may be used to configure, control, and update the system software.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Dynamic IP Addresses By default, the SoundStructure device accepts an IP address from a DHCP server. Once assigned, IP addresses can be determined with the SoundStruc- ture Studio software via the SoundStructure device discovery method. To determine the IP address, connect to the device using the Connect to Devices option as shown in the following figure.
Network Management By default the system name is set to “SoundStructure System” as shown in the next figure. The system name is used to easily identify units and can be set with the Sound- Structure Studio as shown in the previous figure by entering the name and pressing the Apply button or by using the sys_name API command as shown below.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 To configure the device to have a static IP address, use the eth_settings com- mand as follows: set eth_settings 1 “type='static',addr='192.168.1.101',gw='192.168.10.254',nm='255.255.25 5.0',dns='66.82.134.56'” where the 1 represents the device ID of the SoundStructure. If multiple Sound- Structure devices are linked together, the device id of the first unit will be 1 and subsequent connected devices will have sequential device id’s ranging...
To set the address to a static IP address, follow this example: set eth_settings 1 “mode='static',addr='172.22.2.110',dns='172.22.1.1 172.22.1.2', gw='172.22.2.254',nm='255.255.255.0'" All the arguments to the eth_settings command must be specified when the mode is set to ‘static’. Setting The Time Server To set the time server, use the command ntp_server as shown in the example below: set dev_ntp_server 1 “pool.ntp.org”...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The command responses are received back and include the mute status for all virtual channels in the “Mics” virtual channel group. When there are multiple simultaneous control sessions to a SoundStructure system, the control session that sends commands will also receive command acknowledgements for all of its commands.
AMXB<-UUID=001122334455><-SDKClass=AudioConferencer><-Make=Polycom> <-Model=SoundStructureC16><-Revision=1.0.0><Config-Name=SoundStructure C16 Configuration> <Config-URL=http://172.22.2.109/> where 001122334455 is the MAC address of the SoundStructure C16 device in this example. RS-232 The RS-232 interface is capable of running up to 115,200 bps and has a default rate of 9,600 bps, eight data bits, no parity, one stop bit (8-N-1).
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The RS-232 port may be used for control sessions or for configuration with SoundStructure Studio. Configuring And Accessing The Logs The SoundStructure device logs include the following information and may be retrieved from the device using SoundStructure Studio.
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Network Management API commands correspond to the commands that were sent to the system and how they were transmitted, IP or RS-232. API command responses show the command acknowledgment and where the response was directed. 8 - 9...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 8 - 10...
1 Microphone And Mono Video Conferencing This simple example is designed to show how to get started designing with the SoundStructure products. In this example one microphone and a Polycom VSX8000 will be used with a SoundStructure C8 device. The block diagram of this system is shown in the following figure. The channel names are labeled with the virtual channel names that are created by default by the SoundStructure Studio software.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Before proceeding with the design, install SoundStructure Studio software from the CD-ROM supplied with your SoundStructure device or download the latest version from the Polycom website. Launch the SoundStructure Studio software and select New Project from the File menu.
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Advanced Applications Step 2 - Select Outputs For the second step, select a mono amplifier as the output source. The VSX8000 output is automatically defined when the VSX8000 input is selected. Step 3 - Select Equipment Select the equipment required to create this design. By default a SoundStruc- ture C8 is selected.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Step 4 - Work Offline Or Online In this step offline operation is selected to create a file for later upload into a SoundStructure C8. Channels Page Once the design has been created, the user is presented with the Channels page where the following virtual channels and virtual channel groups have been defined.
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Advanced Applications nel is set to 0dB, in other words, no gain is applied. It is also assumed that the Amplifier can accept the nominal 0dBu level from the SoundStructure device, allowing the SoundStructure Amplifier output to have 0dB output gain. If the Amplifier input has an RCA connection, the Amplifier output gain adjusted from 0dB to -10dB to prevent overdriving the consumer-level input on the Amplifier.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Matrix Settings The matrix page shows how the input signals are mapped to the output sig- nals. In this example, the tabletop microphone is sent to the VSX8000 and the VSX8000 is sent to the local amplifier.
Advanced Applications output 2. If this wiring scheme does not match how the system has been wired, the channels may be moved around on the wiring page to their desired locations. Controlling The System A control system will typically be used to mute the microphone and adjust the volume settings in the local room.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Volume Control Volume control in the room can be accomplished by adjusting the fader con- trol on the “Amplifier” virtual channel as follows: inc fader “Amplifier” 1 will increase the gain on the “Amplifier” channel by 1dB and dec fader “Amplifier”...
The VTX1000 must be configured for “Vortex” mode to route the appropriate signals to and from the Aux In and Aux Out connectors on the VTX1000 power supply. The VTX1000’s microphones and loudspeaker are not used in this configuration. Advanced Applications POLYCOM POLYCOM POLYCOM POLYCOM 9 - 9...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The block diagram of this system is shown in the following figure. The From VTX1000 and To VTX10000 signals are wired to the VTX1000 power module as shown in the following figure.
Advanced Applications SoundStructure Studio Steps The steps to create this project are shown in the following figures. The names for the channels are the names that SoundStructure Studio defines. Step 1 - Select Inputs Select four HDX digital tabletop microphones and a mono program audio source.
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VTX1000 input is defined. Step 3 - Select Devices Select the equipment required to create this design. By default the SoundStruc- ture C16 is selected. Note that no telephony card is required as the VTX1000 will be the telephony interface. 9 - 12...
Step 4 - Work Offline Or Online In this step offline operation is selected to create a file for later upload into a SoundStructure C16. Matrix Settings Once the system has been designed, click the Matrix label in the project window to view the matrix shown in the following figure.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The microphones “Table Mic 1 A” through “Table Mic 4 C” are routed to the “VTX1000 Out” channel using the conferencing signal path which includes echo and noise cancellation, and automixer processing. The blue background of these crosspoints is the visual indicator that the conferencing version of the input processing has been selected.
Advanced Applications The matrix may be collapsed by clicking the up arrows next to the “Mics” group. Because all the microphones are used in the same way, the group cros- spoint represents how all the table microphone channels are being used. The result is a compact matrix representation as shown in the following figure.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 By default the AEC reference has been set to the mono virtual channel “Ampli- fier” because this audio includes all the remote audio that need to be echo cancelled.
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Advanced Applications On the VTX1000 out channel, change the gain from -5 to -10 as shown in the following figure. This change is to ensure the SoundStructure’s output signals at 0du do not overdrive the input of the VTX1000 which is expecting a -10dBu nominal signal.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 After this output gain change, and any other changes that are made to the file, the next step is to save the settings to the power on preset as shown on the pre- sets page and in the following figure to ensure all changes are stored permanently inside the system.
Advanced Applications tion. The digital microphone arrays require the processing of 12 analog inputs and are assigned to inputs 5 - 16 automatically, leaving the first four analog inputs available to be used with analog signals. Controlling The System While a control system can be used to adjust volume levels and to mute the signal paths, this example uses the SoundStation VTX1000 to control the tele- phone line, muting status of the send signal to the remote telephony participants, and the in room level of the telephone signal.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 8 Microphones, Video, And Telephony Application This example creates a typical mono conferencing system with eight table microphones, mono program audio, a mono video codec, and a single audio amplifier zone.
Advanced Applications SoundStructure Studio Steps The steps to create this project are shown in the following figures. The names for the channels are the names that SoundStructure Studio defines. Step 1 - Select Inputs Select eight table microphones, a mono program audio source, a VSX8000 mono video codec, and a telephone interface.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Step 3 - Select Devices Select the equipment required to create this design. By default the SoundStruc- ture C12 with a single line telephone card is selected. Step 4 - Work Offline Or Online In this step offline operation is selected to create a file for later upload into a SoundStructure C12 and TEL1 single-line telephony card.
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Advanced Applications The input virtual channels that include remote audio are the “Phone In”, “Pro- gram Audio”, and “VSX8000 In”. These channels are routed to the “Amplifier” channel so they can be heard in the local room. The microphones “Table Mic 1” through “Table Mic 8” are routed to the “Phone Out”, “VSX8000 Out”, and “SubMix Mics”...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The matrix may be collapsed by clicking the up arrows next to the “Mics” group. Because all the microphones are used in the same way, the group cros- spoint represents how all the table microphone channels are being used. The result is a compact matrix representation as shown in the following figure.
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Advanced Applications By default the AEC reference has been set to the mono virtual channel “Ampli- fier” because this audio includes all the remote audio that need to be echo cancelled. 9 - 25...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Wiring Information The system should be wired according to the layout on the wiring page as shown in the following figure. To wire the system with virtual channels on...
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Advanced Applications set mute “Mics” 1 will mute all the microphones in the system and set mute “Mics” 0 will unmute the microphones in the system. Volume Control Volume control in the room can be accomplished by adjusting the fader con- trol on the “Amplifier”...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Two PSTN Line Positional “Receive” Audio Conferencing This example creates a positional receive audio conferencing system using two telephony lines to represent two remote participants. The system is called “positional received”...
The block diagram of this system is shown in the next figure. The channel names are labeled with the virtual channel names that are created by default by the SoundStructure Studio software. To create this design, start the SoundStructure Studio software and follow the steps shown in the next section.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Step 1 - Select Inputs Select 8 table microphones, a stereo program audio source, and two telephone interfaces. Step 2 - Select Outputs Select two mono amplifiers as the output devices for this example. The tele- phone outputs are automatically defined when their respective inputs are added.
Advanced Applications Step 3 - Select Equipment Select the equipment required to create this design. By default the SoundStruc- ture C12 with a dual-line telephone card is selected. Step 4 - Work Offline or Online In this step offline operation is selected to create a file for later upload into a SoundStructure C12 and dual-line telephony card.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 By default the two telephone lines are routed to both “Amplifier 1” and “Amplifier 2” and the stereo program audio “Program Audio” channel is routed as a mono signal to both Amplifier 1 and Amplifier 2 as shown in the next figure.
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Advanced Applications amplifier outputs can be adjusted with the balance control as shown in the fol- lowing figure. The program audio is balanced to the left to “Amplifier 1” and to the right to “Amplifier 2”. 9 - 33...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The matrix may be collapsed by clicking the arrows next to the “Mics” group resulting in the compact matrix representation shown in the following figure. This figure also shows the routing of each telephony interface to the other tele- phony interface so that both callers can hear the other caller.
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Advanced Applications By default the two AEC references have been set to the two mono amplifiers “Amplifier 1” and “Amplifier 2” and is then shown to be in stereo mode. 9 - 35...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Wiring Information The system should be wired according to the information found in the wiring page and shown in the next figure. To wire the system with virtual channels...
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Advanced Applications will unmute the microphones in the system. Volume Control Volume control in the room can be accomplished by adjusting the fader con- trol on the “Amplifier 1” and “Amplifier 2” virtual channel as follows: inc fader “Amplifier 1” 1 will increase the gain on the “Amplifier 1”...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 No change to the AEC reference would be required as the AEC reference uses both “Amplifier 1” and “Amplifier 2” and will work whether there is one or two phone lines connected.
8 Microphones And Stereo Video Conferencing This example creates a stereo video conferencing system with eight table microphones, stereo program audio, a VSX8000 stereo video codec, and a stereo audio amplifier. This application is similar to the 8 microphone mono example shown previously with the addition of the stereo video codec that enables both a positional “receive”...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Once the design is completed, the matrix looks very similar to the mono con- ferencing case with the exception that the “Program Audio”, “VSX8000 In”, “VSX8000 Out”, and “Amplifier” virtual channels have the stereo graphic symbol next to their names signifying they are stereo virtual channels as shown in the following figure.
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The remote participants at site 2 will see the site 1 talker at microphone 1 on the right side of their screen when the remote talkers are looking at the screen because the site 1 talker at microphone 1 is on the “right” side of the camera from the camera’s perspective.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The relative position for microphone 1 can be set at the matrix crosspoint to 0.4 as shown in the following figure. This means that the microphone is panned to the right by 0.4.
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The other microphones also have relative positions as shown in the following figure. Camera Display Right Reference Point RIGHT Room Left Advanced Applications Camera Display Display Left Camera LEFT Room Right Site 1 9 - 43...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 By estimating their pan position, the resulting matrix will look like the next fig- ure. As microphones move from right to left relative to the camera, their panning is adjusted from positive to negative.
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Advanced Applications By default the AEC reference has been set to the stereo virtual channel “Ampli- fier” and is then shown to be in stereo mode. 9 - 45...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Wiring Information The system should be wired according to the information found in the wiring page and shown in the following figure. To wire the system with virtual chan-...
This example shows how to use 8 analog microphones with a SoundStructure device connected to a Polycom HDX video conferencing system. This system will use the telephony interface that is native to the Polycom HDX system. A drawing of this type of system is shown in the following figure.
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Chapter 6. Step 2 - Select Outputs Select a stereo amplifier as the output source. Notice that the Polycom HDX is already defined as an output and includes multiple audio streams that will be sent to the HDX from the SoundStructure device.
Advanced Applications Step 3 - Select Devices Select the equipment required to create this design. By default the SoundStruc- ture C8 is selected. Step 4 - Work Offline Or Online In this step offline operation is selected to create a file for later upload into a SoundStructure C8.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The input virtual channels include microphones that are included in the vir- tual channel group “Mics” collapsed as shown in the next figure and the remote audio from the Polycom HDX. The Polycom HDX audio channels are routed to the “Amplifier”...
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Advanced Applications By default the AEC reference has been set to the mono virtual channel “Ampli- fier” because this audio includes all the remote audio that need to be echo cancelled. 9 - 51...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Wiring Information The system should be wired according to the layout on the wiring page as shown in the following figure. To wire the system with virtual channels on...
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0dB. When connected to the Polycom HDX system, the Amplifier fader setting on the SoundStructure will be adjusted when the volume on the Polycom HDX is adjusted. As described in Chapter 6, the HDX will send a fader command to the “Amplifier”...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 8 Mics With Reinforcement Of Wireless And Lectern Mics This example shows how to use the sound reinforcement and conferencing processing to create an audio conferencing solution that includes both a lectern and wireless microphone for in-room reinforcement of the presenters’...
The block diagram of this system is shown in the following figure. The channel names are labeled with the virtual channel names that are created by default by the SoundStructure Studio software. SoundStructure Studio Steps Creating the design described in the previous section will require a Sound- Structure C12 and single line telephony solution.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Matrix Settings The matrix that is created by SoundStructure Studio is shown in the following figure. To add the reinforcement of the wireless and lectern microphones, the lectern microphone will only be reinforced into Amplifier zones 2 and 3 and not in Amplifier zone 1.
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Advanced Applications All microphones are sent to the remote telephony participant as shown with the routing of the conferencing version of the microphones to the “Phone Out” virtual channel. The resulting matrix will look like the following figure. 9 - 57...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Channels Settings The next step is to enable the feedback processing on the wireless and lectern microphone. This can be done from the channels page by clicking on the EQ button for the “Presenter Mics”...
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Advanced Applications To ensure the wireless microphone will be the active microphone if the pre- senter with the wireless microphone is picked up by another nearby microphone, the automixer channel bias for the wireless microphone will be set to 6dB as shown in the following figure. Finally, it is necessary to review the AEC reference for the different micro- phones to ensure that acoustic echoes are cancelled in the system.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The first step to creating the wireless microphone’s reference is to build this reference by creating a new submix called “WirelessRef” as shown in the fol- lowing figure. The AEC reference for the wireless microphone is assigned to the new submix as shown in the next figure.
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Advanced Applications The same approach can be taken with the lectern microphone, creating a submix called “LecternRef” that includes the reinforced wireless microphone, the remote audio sources, and the program audio. The new matrix will appear as shown in the following figure. The AEC reference for the lectern mic can then be set to the “LecternRef”...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Finally, the reference for the table microphones can be set to include both the lectern and wireless microphone references. Since two references can be con- figured per microphone, the first reference will be set to “WirelessRef” and the second reference will be set to “LecternRef”.
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Advanced Applications The “RemoteAudio” submix will also be routed to the different amplifier zones and remote telephone participants. 9 - 63...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Wiring Information The system should be wired according to the information found in the wiring page and shown in the next figure. To wire the system with virtual channels...
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Advanced Applications The reinforcement of the wireless microphone may be disabled by muting the reinforced crosspoints as shown next. set matrix_mute “Wireless Mic” “Amplifier 1” 1 set matrix_mute “Wireless Mic” “Amplifier 2” 1 set matrix_mute “Wireless Mic” “Amplifier 3” 1 The reinforcement of the wireless microphone may be enabled by setting the mute status to 0.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 16 Mics With 6-Zone Sound Reinforcement This example shows how to use the sound reinforcement and conferencing processing to create an audio conferencing solution that includes a lectern microphone, wireless microphone, and sixteen tabletop microphones that are reinforced into the room.
Advanced Applications SoundStructure Studio Steps Step 1 - Select Inputs The system is designed with 16 table microphones, one lectern mic, one wire- less mic with line level input, one stereo VSX8000 video codec, and a single telephony interface. 9 - 67...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Step 2 - Select Outputs Six mono audio amplifiers are added to the system in this step. The output to the telephone line and VSX8000 were created when their respective input com- ponents were added to the system in step 1.
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Advanced Applications Step 4 - Work Offline Or Online As there are many matrix settings to change, we’ll work off line and adjust the crosspoints. 9 - 69...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Matrix Settings The default matrix with the desired inputs and outputs is shown in the follow- ing figure. 9 - 70...
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The next step is to create the microphone zone groups that will simplify setting up the reinforcement levels. The designed zones are shown in the following figure. Zone 1 Zone 2 Zone 3 As part of the design process, the appropriate reinforcement levels would be determined and a mapping similar to the one shown in the following figure would be created as the baseline reinforcement in the room.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 zones. For example, the zone 1 microphones are mapped to zones 2, 3, 4, 5, and 6 with a gain of -9, -6, -6, -9, and -12dB respectively. The zone numbering matches the room layout description.
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Advanced Applications The next step is to map the stereo program audio and video codec audio to the appropriate left and right loudspeakers in the room. The result is shown in the following figure where the left channel of the audio is panned to the amplifiers in zones 1, 2, and 3 and the right channel of the audio is panned to amplifiers 4, 5, and 6.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Channels Settings Once the matrix has been configured, the next step is to enable the feedback processing for each microphone. This can be done easily with the channels page editing the EQ settings for the “Mics” group as shown in the following figure.
Advanced Applications ences, and Zone 3 and Zone 4 microphones will have Zone 3 and Zone 4 amplifiers selected as shown in the next figure. This figure shows the Zone 1 microphones. The references for the lectern microphone can also be set to the Zone 1 and Zone 6 amplifiers.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The first C12 is configured to be bus id 1 and the second is configured to be bus id 2 by default assuming the OBAM out of the first device is connected to the OBAM in on the second device.
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Advanced Applications set mute “Mics” 0 The in-room volume for the remote audio may be increased with the fader command on the phone or video codec audio as follows. inc fader “VSX8000 In” 1 inc fader “Phone In” 1 to increase the gain on the faders - making the “VSX8000 In” and “Phone In” channels louder in the local room.
PSTN line, a program audio feed, a loudspeaker zone, and one digital micro- phone array in each room. In addition, room 1 also has a Polycom HDX video conferencing system that is used with all microphones when the rooms are combined and only in room 1 when the rooms are split.
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The room configuration will operate as follows. Combined Mode In the combined mode, the system is configured as follows: • All microphones are routed to both telephone lines • Both telephone lines are routed to the HDX system Advanced Applications Display POLYCOM POLYCOM 9 - 79...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 • • • • • Split Mode In the split mode, the system is configured as: • • • • • Similarly for Room 2: • • • •...
Advanced Applications SoundStructure Studio Steps Step 1 - Select Inputs The system should be designed in the combined mode with two HDX table microphones, two program audio source, two telephone lines, and a Polycom HDX system. 9 - 81...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Step 2 - Select Outputs Two mono amplifiers will be selected in this step. The output to the telephone lines and the output to the HDX 9000 were created when their respective input components were added to the system in step 1.
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Advanced Applications Step 4 - Work Offline Or Online As there are many matrix settings to change, we’ll work off line and adjust the crosspoints. 9 - 83...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Combined Room Settings The default matrix with the desired inputs and outputs is shown in the follow- ing figure. The next steps are to rename the “Mics” virtual channel to “Room 1 Mics” and change the membership to only include Room 1 microphones, add the group “Room 2 Mics”...
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Advanced Applications The updated matrix is shown in the following figure. In this matrix, the submix “Amplifier” is used to route the remote audio of the combined system to the “Amplifier 1” virtual channel and the “Mics” submix is used to send the combined microphones to the remote video participants and to the “Phone 1 Out”...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 On the channels page, set the AEC reference for all the Room 1 microphones as “Amplifier 1” and for the room 2 microphones as “Amplifier 2” as shown in the following figure.
Advanced Applications Split Room Settings In the split room configuration, the matrix settings must be adjusted to route the audio to meet the original specifications. The following figure shows the routing that keeps the audio from the two rooms completely separate while routing the HDX audio to only Room 1.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The automixer settings for the Room 1 mics is shown in the following figure after the Room 2 microphones have been removed. 9 - 88...
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Advanced Applications The automixer settings for the Room 2 mics is shown in the following figure after setting the Automixer Group to 2 and adding the Room 2 microphones. No adjustments need to be made to the echo canceller references because the microphones were configured earlier to use their respective room amplifiers as the AEC reference.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Finally, confirm that there is a power on preset - in this example it should be set to be the “Combine” preset as shown in the following figure. Wiring Information The system should be wired according to the information found in the wiring page and shown in the following figure.
Advanced Applications In this example, a single C8 device was used to implement the design. This device is wired as shown in the following figure. The digital microphone arrays use the processing from inputs 3 - 8, leaving inputs 1 and 2 available for the program audio sources.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 to increment the gain in the combined Amplifier by 1 dB. In the split mode, this command would increment only the Room 1 amplifier by 1dB since only the Room 1 remote audio sources are routed to the “Amplifier”...
TroubleShooting This chapter presents a series of situations and troubleshooting steps to resolve the situation. Troubleshooting is most effective when problems can be isolated, reproduced, and then resolved one at a time. This “divide-and-con- quer” approach will be used in this chapter. Audio Troubleshooting Many audio problems can be traced to the following issues: 1.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Is the amplifier turned on? Can other sources of audio be heard in the local room? Add a Signal Generator from the Edit Channels control and route the signal generator to the amplifier virtual channel.
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TroubleShooting Also ensure the sound reinforcement signal path is selected at the matrix cros- spoint. There should be a light blue background on the crosspoints routing the microphones to be reinforced to the audio amplifier as shown in the following figure where “Table Mic 1”...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Echo Troubleshooting Many echo problems can be traced to: 1. Check loop-back echo. A matrix cross-point may have been inadvertently 2. AEC Reference is setup incorrectly (see chapter 5). Note: AEC reference 3.
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An example of the “Amplifier” channel and all the remote audio sources that make up the “Amplifier” channel is shown in the following figure. Notice that the audio from the Polycom HDX, the telco audio, the program audio, and the audio from the remaining remote source are all part of the “Amplifier”...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 reduce room gain by lowering the audio amplifier level and increasing the input gain on the remote audio coming into the SoundStructure to ensure the signal levels are at a reasonable level.
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TroubleShooting Because the AEC reference is available after the fader as presented in Chapter 3 and shown in the following figure, the result is that the AEC reference is also attenuated and therefore the echo canceller would not be able to remove the echo because the reference level is attenuated too much.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 the following figure. The result of this is that the proper signal levels are pre- sented to the echo canceller and the output signal levels are attenuated appropriately. The Local People Hear Echo Of Their Voices From The Remote Room This problem is most likely with the remote room’s acoustic echo canceller.
TroubleShooting API Troubleshooting When using TeraTerm 3.1 and connecting over Telnet, why do I have to select CR-LF termination for commands sent to SoundStructure and not just CR termination? As described in Appendix A, SoundStructure devices accept commands sent to it with either CR or CR-LF terminations. What we noticed is that when using Tera Term in telnet mode, Tera Term terminates commands transmitted to SoundStructure with two bytes - CR and a Null character - even though only the CR termination is selected in the Tera Term user interface.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 will cause this error message. Fix this syntax by putting double quotes around the virtual channel name such as with the command set mute “Table Mic 1” 1 and the system will work properly.
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Reboot the SoundStructure device and see if it is possible to connect to the device either via RS-232 or Ethernet. If so, check the Polycom website for a newer version of firmware and release notes to see what issues may be been resolved.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 RS-232 Troubleshooting I Can’t Connect Over RS-232 To The System, How Do I Connect? Check that the baud rate between the PC or Control system and the Sound- Structure device are set to the same value. Baud rates above 9,600 baud should have hardware flow control enabled on both the SoundStructure device and the control system or local PC.
1 none where 1 is the device ID. HDX Integration How Do I Know The Polycom HDX System Is Connected Properly To The SoundStructure? The Polycom HDX Diagnostics and System Status screen shows whether the SoundStructure device (labeled as Polycom Mixer) has been detected. A green arrow associated with the Polycom Mixer, as shown in the following figure, indicates the systems have detected each other and are working properly.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The connection status can also be viewed within the System Information page on the Polycom HDX. If the status shows Polycom Mixer then the system has connected properly to the SoundStructure.
TroubleShooting Use SoundStructure Studio and from the Channels Page select the phone Set- tings... button to open a telephone keypad. Click the handset icon to take the phone off hook. Check that the virtual channel name used for the telephone channel matches the name used within SoundStructure Studio to create the telephone channel.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 SoundStructure Studio Can’t Find My SoundStructure Device Over Ethernet Depending on network router configurations, SoundStructure Studio may only be able to find devices that are connected to the same subnet as the local PC that is running SoundStructure Studio.
OBAM Troubleshooting There are status LEDs associated with both the OBAM input and output con- nections. These LEDs are positioned on either side of the OBAM link connections as shown in the following figure. The OBAM Input LED will illu- minate when there is a valid OBAM out connection plugged into the OBAM in connection on this device.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Troubleshooting The IR Interface If you are not receiving command acknowledgements from the IR transmitter, make sure the IR transmitter is sending commands. One easy way to test this is to point the IR transmitter at a video camera and see if the IR transmissions light up on the display screen.
IR Receive: Mini (3.5 mm) quick connect terminal block Internal power supply Input voltage of 90-250 VAC; 50-60 Hz Line power requirements (including 0.6 PF): 130 VA (C16), 115 VA (C12), 105 VA (SR12), 95 VA (C8) 11 - 1...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Thermal • • Inputs • • • • • • • Outputs • • • • • System Unless noted, all values are valid for all channels at 0 dB input gain.
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• THD+N: < 0.005%, -20 dB FS input signal • Common mode rejection ratio: <-61 dB, 20-20,000 Hz, no weighting • Cross talk: <-110 dB, 20-20,000 Hz, 1 kHz, channel-to-channel • Latency: Mic/Line inputs to outputs: 23 ms, AEC and NC processing enabled •...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Pin Out Summary Drawings and part numbers are provided for reference only. Other than cables provided by Polycom, Polycom claims no responsibility or liability for the quality, performance, or reliability of cables based on these reference drawings. Contact a...
Conference Link2 To build a custom Conference Link2 cable, use shielded CAT5e, or better, and terminate both end connectors, P1 and P2, with standard 8P8C plugs (for example, RJ45) using the wiring connections shown in the following figure. The maximum length for this cable is 100 feet (30 m). Note that this cable provides a cross-over connection between pins 1 and 2 and pins 5 and 6.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 OBAM Link The OBAM cable is a standard 1394b BETA style cable. The maximum length of this cable is 10 feet (3 m). While OBAM Link uses 1394b cables, the underlying bus protocol is not IEEE1394b compliant which means that external IEE1394b devices will not be compatible with OBAM Link.
IR Receiver The IR receiver port on the rear-panel of a SoundStructure device is shown in the next figure. The IR receiver port accepts a standard 3.5 mm terminal block which should be terminated to the IR receiver as shown in the following figures. RS-232 The RS-232 interface requires a straight-through cabling to a control system as shown in the following figures.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Logic Interface 11 - 8 SoundStructure Signal Ground Pin 13 Pin 25 REMOTE CONTROL 1 Pin 13 Pin 25 REMOTE CONTROL 2 Remote Control 1 Signal +5 V Logic Output 1...
Audio Connections SoundStructure devices provide balanced audio input and output connections that are terminated with 3.5 mm terminal blocks as shown in the following figure. For each balanced analog input or output on the SoundStructure rear-panel, the first pin should be connected to the positive signal, the second pin is connected to the negative signal, and the third pin is chassis ground as shown in the balanced audio connections in the following figure.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 SoundStructure device's audio input and output to other balanced or unbalanced audio equipment, follow the wiring convention in the unbalanced audio connections in the following figure. 11 - 10...
Using SoundStructure Studio Controls The SoundStructure Studio software environment includes various user inter- face controls for adjusting the parameters of virtual channels. This section summarizes how to use these controls. Adjusting Knobs There are three ways to change the value associated with a knob control: 1.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Adjusting Matrix Crosspoints Individual crosspoints can be adjusted by double clicking the crosspoint. This will bring up the matrix control that allows the crosspoint gain, mute status, or which of the three flavors of the input signal to select for this matrix crosspoint.
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Using SoundStructure Studio Controls 12 - 3...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 12 - 4...
Some features will only be practical over the higher bandwidth connections (for example, firmware updates take much less PIN 2: TXD PIN 3: RXD PIN 5: GROUND PIN 7: CTS PIN 8: RTS REMOTE CONTROL 1 RS-232 REMOTE CONTROL 2 OBAM SoundStructure C16 A - 1...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 time over the ethernet interface than the RS-232 interface and signal meters are more responsive over the ethernet interface). While the SoundStructure Studio Windows software makes full use of the control protocol to configure and control SoundStructure, user applications, such as AMX®...
Ethernet Each SoundStructure device has a rear-panel Ethernet interface for connecting to the local area network as shown in the following figure. Connect to the SoundStructure device using port 52774 and telnet communication. There is no user login required to interface to SoundStructure devices over this port. Control systems and PCs running SoundStructure Studio may communicate with SoundStructure over this interface using port 52774.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 used to connect the SoundStructure devices to more than one network. Multiple network connections can be on the same network or on different subnets as shown in the following figure.
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The motivation for using virtual channels is both to allow the control system programming to start before the physical wiring may be known and to make the control system programming re-usable across different installations regardless of how the system is wired. Virtual channels allow third-party control system code to be easily re-used because the controller code controls the SoundStructure devices through the virtual channel names, not the underlying physical input and output that a particular channel is connected to.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Virtual Channel Types Virtual channels are operated on by the command set which can apply parameter changes to the underlying physical channels. For example, setting the fader parameter of a virtual channel would set the fader parameter for its underlying physical channels.
As an example of a virtual channel group, consider in the following figure the creation of the virtual channel group “Mics” made up of the entire collection of individual microphone virtual channels in a room. Once the virtual channel group “Mics” has been created, it is possible to configure and control all the microphones at the same time by operating on the “Mics”...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Controlling SoundStructure Parameters The SoundStructure command and control functions allow an external controller to set, query, and monitor parameters of one or more linked SoundStructure devices. There are three types of parameters that can be controlled: •...
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Command Protocol Reference Guide void Void commands take no argument, and must be write-only. For example, the sys_reboot parameter is a write-only void parameter that reboots the SoundStructure device when the command is executed. boolean Boolean parameters take one of two values: 0 or 1. integer Integer parameters represent an integer value.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Command Format Referring to the command hierarchy below, each sub-category of command inherits the syntax of its parent and adds further syntax requirements. Starting at the root of the hierarchy, all commands have the following syntax: <action>...
Command Protocol Reference Guide Command Length All commands must be less than or equal to 2048 bytes in length, including the terminator. Control Commands Most of the commands in the SoundStructure control protocol fall under the category of control commands. All control commands have the following syntax: <action>...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Floating-Point Arguments Floating-point arguments represent a floating-point value. They are represented using a string of digits (0030-0039), an optional decimal point symbol (002E), an optional E (0045) or e (0065) for indicating an exponent, and optional plus symbols (002B) or minus symbols (002D) for indicating the sign of the mantissa or exponent.
Virtual Channel Definition Commands Virtual channel definition commands are a type of control command that provide methods for defining virtual channels and mapping them to physical channels. The SoundStructure Studio software will create the virtual channel definitions based on the input and output selections the designer has chosen. The syntax described below is what SoundStructure Studio uses to create the channel definitions.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Virtual channel type stereo control control_array <pctype> The <pctype> argument defines the physical channel type of the physical channels in the virtual channel. The <pctype> argument is a system defined text argument that must be one of the following.
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“ir receiver” control ir_in 1 This creates the virtual channel name “ir receiver” that will report back any IR key presses that are received using the standard Polycom HDX IR receiver that has been set to a device ID of 3.
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The acknowledgement will be sent to all interfaces. As an example, consider two C16 linked via OBAM link, and assume that no virtual channels are defined. If a control system connected to any of the control interfaces of a SoundStructure device sends the following command: vcdef "Stereo Mics"...
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Command Protocol Reference Guide <pctype> The <pctype> argument defines the physical channel type of the physical channels in the virtual channel. The <pctype> argument is a system defined text argument that must be one of the pctypes listed in the vcdef section. <num>...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The <label> argument is a user-defined text argument that specifies the name of the virtual channel to be renamed. If no virtual channel exists with the given label, then the SoundStructure device will respond with an error message.
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Command Protocol Reference Guide vcgdef <label> [<vcmember> [<vcmember> ... ]]<term> Each of the command arguments is described below. <label> The <label> argument is a user-defined text argument that defines the name for the new virtual channel group. If a virtual channel group or virtual channel already exists with the same label, the SoundStructure device will respond with an error message.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 vcgrename Action The vcgrename action is a virtual channel group definition command that changes the name of a virtual channel group. Commands with the vcgrename action have the following syntax: vcgrename <label>...
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Command Protocol Reference Guide respond with an error message. If the virtual channel is already a member of the virtual channel group, the SoundStructure device will respond with an error message. vcgadd Acknowledgements When a virtual channel group definition command with the vcgadd action is successfully executed, the SoundStructure device will send an acknowledgement in the same format as the command.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Each of the command arguments is described below. <label> The <label> argument is a user-defined text argument that specifies the name of the virtual channel group that will have its members listed. If no virtual channel group exists with the given label, then SoundStructure will respond with an error message.
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Parameter Command Syntax All parameter commands have the following syntax. <action> <param> [<limit>] [<chan> [<chan>]] [<index> [<index> ...]] [<arg>]<term> Some examples of parameter commands are given below. get sys_sw_ver 1 set mic_in_gain "DVD Audio" 10 set fader max "DVD Audio" 10 inc fader "DVD Audio"...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Some parameters support user-definable minimum and maximum values. For these commands, the <limit> argument can be specified. The <limit> argument is a system-defined text argument and can be one of the following...
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Command Protocol Reference Guide Thus, read-write commands support the get and set actions and support the inc, dec, or tog actions depending on the parameter type. Read-only commands support the get action, but do not support the set, inc, dec, or tog actions.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Float parameter commands support the get, set, inc and dec actions according to the command’s read-write mode. When performing increment and decrement actions on float parameters, the parameter saturates at the minimum or maximum value rather than wrapping.
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Acknowledgements are generated when either a parameter command is issued or a parameter changes value for some other reason. When a parameter command is executed with the get action, the acknowledgement is only sent to the control interface that the parameter command was received from. When a parameter command is executed with the get action, the acknowledgement is only sent to the control interface that the parameter command was received from.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Command List The complete system parameter command reference is found in the file soundstructure-parameters.html on the CDROM and may also be found by browsing in the SoundStructure device’s web interface by pointing a browser at the IP address of the SoundStructure device.
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(used with the SR12), telephony input and output channels, submix channels, and the ConferenceLink channels to and from the Polycom HDX video system. The Virt Chans entry indicates that the command can operate on both mono and stereo virtual channels.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 set fader "Amplifier" 10 val fader "Amplifier" 10.0 set fader max "Amplifier" 10 val fader max "Amplifier" 10.0 set fader min "Amplifier" -20 val fader min "Amplifier" -20.0 get fader "Amplifier"...
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Argument System Limits Default User Limits Supported Description This parameter sets the fader level (in dB) in the digital domain. Examples Command Response set fader "Amplifier" 1 val fader "Amplifier" 1 get fader "Amplifier" val fader "Amplifier" 1 set fader max "Amplifier" val fader max "Amplifier"...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Argument Virt Chans System Limits Default User Limits Supported Description This parameter sets the gain (in dB) of the line output. Examples Command Response set line_out_gain val line_out_gain "Amplifier" -10 "Amplifier"...
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set mic_in_gain "Table val mic_in_gain "Table Mic 1" 48 Mic 1" 48 mute Digital Mute Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans Default Description This parameter sets the mute status of the virtual channel. A value of 0 indicates the virtual channel is unmuted, while a value of 1 indicates it is muted.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 phantom 48 V Phantom Power Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans Default Description Enables or disable phantom power on mic inputs. Setting phantom to 1 enables phantom power, while setting it to 0 disables phantom power.
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trim Gain Trim For Virtual Channels Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans Indices System Limits Default User Limits Supported Description This parameter applies gain (in the analog domain) to the individual components of a virtual channel. The index indicates to which physical channel of the virtual channel the trim will be applied.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Matrix Parameters matrix_balance Matrix Crosspoint Balance Argument Channel Type Value Type Read/Write Mode Row Phys Chans Row Virt Chans Col Phys Chans Col Virt Chans System Limits Default User Limits...
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matrix_gain Matrix Crosspoint Gain Argument Channel Type Value Type Read/Write Mode Row Phys Chans Row Virt Chans Col Phys Chans Col Virt Chans System Limits Default User Limits Supported Description This parameter sets the gain (in dB) for the specified crosspoint in the matrix mixer.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Argument Row Phys Chans Row Virt Chans Col Phys Chans Col Virt Chans Default Description This parameter selects whether the gated (1) or ungated (0) version of the input signal is sent to the output.
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Description This parameter selects the gating style for crosspoints with conferencing inputs. TODO: describe properties of the different gating styles. Gating is enabled with the matrix_gate parameter. Examples Command Response set matrix_gate_type val matrix_gate_type "Table Mic 1" "Phone Out" "Table Mic 1" "Phone Out" conf conf set matrix_gate_type...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 matrix_mute Matrix Crosspoint Mute Argument Channel Type Value Type Read/Write Mode Row Phys Chans Row Virt Chans Col Phys Chans Col Virt Chans Default Description Mutes or unmutes the specified crosspoint in the matrix mixer. Setting matrix_mute to 0 unmutes the crosspoint;...
Argument Col Phys Chans Col Virt Chans System Limits Default User Limits Supported Description The matrix_pan parameter is available at crosspoints where mono virtual channels are mixed to stereo virtual channels. The matrix_pan parameter provides a way to control the amount of gain going to the left and right channels.
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phone_auto_answer_en Enable Auto-Answer For Telephony Interface Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans Default Description This parameter enables (1) or disables (0) the auto-answer feature for the telephony interface. Examples Command Response phone_auto_answer_en phone_auto_answer_en "Phone In" 1 "Phone In"...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 set phone_connect val phone_connect "Phone Out" 1 "Phone Out" 1 get phone_connect val phone_connect "Phone Out" 0 "Phone Out" 0 phone_dial Dial The Telephony Interface Argument Channel Type Value Type...
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phone_dial_tone_gain Dial Tone Gain Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans System Limits Default User Limits Supported Description This parameter controls the gain that is applied to the incoming phone signal when dial tone is present. Examples Command Response...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Description This parameter sets the gain (in dB) applied to DTMF tones generated to the local room. To adjust the level of ring tones, entry tones, and exit tones played back into the local room, use the phone_tone_gain parameter.
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Description This parameter enables or disables exit tone generation for the telephony interface. If exit tones are enabled (1), then an exit tone is played whenever the auto-hangup feature engages and disconnects the telephony interface. Entry tones (see the phone_entry_tone_en parameter) and exit tones are typically enabled to prevent a caller from entering or exiting a conference unannounced.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Argument System Limits Default User Limits Supported Description This parameter sets the delay (in milliseconds) for the phone_flash parameter. Note that by default, PSTN interfaces use the flash delay determined by their pstn_country setting.
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Description This parameter indicates the ringing state for the telephony interface. While the telephony interface is ringing, reading this parameter will return 1. When the telephony interface is not ringing, reading this parameter will return 0. Acknowledgements for this parameter will be automatically sent whenever this parameter changes state due to a hook flash, auto-answer, or auto-hangup.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Argument Virt Chans System Limits Default User Limits Supported Description This parameter sets the gain (in dB) applied to tones generated to the local room. In particular, this gain applies to the ring tone, entry tone, and exit tone.
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Argument Argument value Values argentina : Argentina australia : Australia austria : Austria bahrain : Bahrain belgium : Belgium brazil : Brazil bulgaria : Bulgaria canada : Canada chile : Chile china : China colombia : Colombia croatia : Croatia cyprus : Cyprus czech_republic : Czech Republic denmark : Denmark...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Argument Values Values A - 52 Argument value italy : Italy japan : Japan jordan : Jordan kazakhstan : Kazakhstan kuwait : Kuwait latvia : Latvia lebanon : Lebanon...
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Description This parameter configures the PSTN interface for operation in a specific country. pstn_flash_delay_override Override Country Code Flash Delay Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans Default Description This parameter controls whether or not the flash hook delay is determined by the default pstn_country settings (0) or by the phone_flash_delay setting (1).
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 set pstn_in_gain "Phone val pstn_in_gain "Phone In" 6 In" 6 pstn_line_voltage PSTN Line Voltage Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans System Limits Description This parameter indicates the line voltage (in Volts) of the PSTN interface. The value is valid in both on-hook and off-hook modes.
Description This parameter indicates the loop current (in milliamps) of the PSTN interface. The value is only valid when the interface is off-hook. pstn_out_gain PSTN Output Gain Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans System Limits Default User Limits Supported...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 eq_en Enable All Equalizer Processing Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans Default Description This parameter enables (1) or disables (0) all equalizer processing (peq, geq, etc.) for the specified virtual channel.
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geq_compensate Enable Gain Compensation For Graphic Equalizer Argument Argument value Channel Type Virtual Channel Value Type Boolean Read/Write Mode Read/Write Phys Chans Conferencing Line Output, Sound Reinforcement Line Output Virt Chans Mono, Stereo Default Description This parameter enables (1) or disables (0) gain compensation for the graphic equalizer.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Argument Virt Chans Indices System Limits Default User Limits Supported Description Set the gain of the specified band in the graphic equalizer. The index must be between 1 and 10 for 1 octave equalization, between 1 and 15 for 2/3 octave equalization, and between 1 and 31 for 1/3 octave equalization.
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Argument Argument value Phys Chans Conferencing Mic/Line Input, Conferencing Line Output, Sound Reinforcement Mic/Line Input, Sound Reinforcement Line Output, Analog Telephony Input, Analog Telephony Output, Submix, ConferenceLink Aux Input, ConferenceLink Aux Output Virt Chans Mono, Stereo Default Description This parameter enables (1) or disables (0) the high shelving filter for the specified virtual channel.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 high_shelf_gain Gain Of High Shelving Filter Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans System Limits Default User Limits Supported Description This parameter sets the gain (in dB) of the high shelving filter at DC.
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horn_en Enable Horn Equalizer Argument Argument value Channel Type Virtual Channel Value Type Boolean Read/Write Mode Read/Write Phys Chans Conferencing Line Output, Sound Reinforcement Line Output Virt Chans Mono, Stereo Default Description This parameter enables (1) or disables (0) the constant directivity horn equalizer for the specified virtual channel.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 hpf_en Enable High-Pass Filter Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans Default Description This parameter enables (1) or disables (0) the high-pass filter for the specified virtual channel.
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hpf_order Order of High-Pass Filter Argument Argument value Channel Type Virtual Channel Value Type Integer Read/Write Mode Read/Write Phys Chans Conferencing Mic/Line Input, Conferencing Line Output, Sound Reinforcement Mic/Line Input, Sound Reinforcement Line Output, Analog Telephony Input, Analog Telephony Output, Submix, ConferenceLink Aux Input, ConferenceLink Aux Output Virt Chans Mono, Stereo...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 low_shelf_en Enable Low Shelving Filter Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans Default Description This parameter enables (1) or disables (0) the low shelving filter for the specified virtual channel.
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low_shelf_gain Gain Of Low Shelving Filter Argument Argument value Channel Type Virtual Channel Value Type Floating-Point Read/Write Mode Read/Write Phys Chans Conferencing Mic/Line Input, Conferencing Line Output, Sound Reinforcement Mic/Line Input, Sound Reinforcement Line Output, Analog Telephony Input, Analog Telephony Output, Submix, ConferenceLink Aux Input, ConferenceLink Aux Output Virt Chans...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 lpf_en Enable Low-Pass Filter Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans Default Description This parameter enables (1) or disables (0) the low-pass filter for the specified virtual channel.
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lpf_order Order Of Low-Pass Filter Argument Argument value Channel Type Virtual Channel Value Type Integer Read/Write Mode Read/Write Phys Chans Conferencing Mic/Line Input, Conferencing Line Output, Sound Reinforcement Mic/Line Input, Sound Reinforcement Line Output, Analog Telephony Input, Analog Telephony Output, Submix, ConferenceLink Aux Input, ConferenceLink Aux Output Virt Chans Mono, Stereo...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 peq_band_en Enable Parametric Equalizer Band Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans Indices Default Description This parameter enables (1) or disables (0) the specified band of the parametric equalizer for the specified virtual channel.
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Description This parameter sets the bandwidth (in octaves) of the specified parametric equalizer band. In the case of peaking filters, this is the bandwidth at which the gain is half the peak gain (in dB). For notch filters, this is the 3 dB bandwidth. For all-pass filters, this is the bandwidth at which the phase shift is +/- 90 degrees.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Argument Phys Chans Virt Chans Indices System Limits Default User Limits Supported Description This parameter sets the gain (in dB) of the specified parametric equalizer band. For conference link physical channels, the band index must be between 1 and 5.
Dynamics Processing Parameters Description Dynamics processing is available on all physical channels except the signal generator and AEC reference. Dynamics processing includes a compressor, limiter, expander, gate, and peak limiter. An additional input gain parameter is provided to change the gain of the signal before the dynamics processor. dp_en Enable Dynamics Processing Argument Channel Type...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Argument System Limits Default User Limits Supported Description This parameter sets the amount of time (in milliseconds) it takes the gate to ramp the gain up to the target gain once the input signal level surpasses the gate threshold.
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dp_gate_en Enable Gate Argument Argument value Channel Type Virtual Channel Value Type Boolean Read/Write Mode Read/Write Phys Chans Conferencing Mic/Line Input, Conferencing Line Output, Sound Reinforcement Mic/Line Input, Sound Reinforcement Line Output, Analog Telephony Input, Analog Telephony Output, Submix, ConferenceLink Aux Input, ConferenceLink Aux Output Virt Chans Mono, Stereo...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 dp_gate_ratio Gate Ratio Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans System Limits Default User Limits Supported Description This parameter sets the ratio of the target gain applied by the gate versus the difference between the input signal level and the gate threshold.
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Description This parameter sets the RMS level (in dBFS) of the input signal below which the gate engages. The level must be below this threshold longer than the gate hold time (set by dp_gate_hold) before the gate begins to apply a gain change. dp_exp_attack Expander Attack Time Argument Argument value...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Argument System Limits Default User Limits Supported Description This parameter sets the amount of time (in milliseconds) it takes the expander to ramp down to the target gain once the input signal drops below the expander threshold.
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Argument Argument value Phys Chans Conferencing Mic/Line Input, Conferencing Line Output, Sound Reinforcement Mic/Line Input, Sound Reinforcement Line Output, Analog Telephony Input, Analog Telephony Output, Submix, ConferenceLink Aux Input, ConferenceLink Aux Output Virt Chans Mono, Stereo System Limits Minimum: 1.0, Maximum: 100.0, Resolution: 0.1 Default User Limits Supported...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 dp_comp_attack Compressor Attack time Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans System Limits Default User Limits Supported Description This parameter sets the amount of time (in milliseconds) it takes the compressor to ramp the gain down to the target gain once the input signal level surpasses the compressor threshold.
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Description This parameter sets the amount of time (in milliseconds) it takes the compressor to ramp the gain up to the target gain once the input signal level drops below the compressor threshold. dp_comp_en Enable Compressor Argument Argument value Channel Type Virtual Channel Value Type Boolean...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Description This parameter sets the ratio of the target gain applied by the compressor versus the difference between compressor threshold and the input signal level. For example, if the compressor ratio is 2 (i.e., 2:1) and the input signal level is 3 dB above the compressor threshold, the compressor applies -1.5 dB of gain.
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Argument Argument value System Limits Minimum: 1, Maximum: 200 Default User Limits Supported Description This parameter sets the amount of time (in milliseconds) it takes the limiter to ramp the gain down to the target gain once the input signal level surpasses the limiter threshold.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 dp_lim_en Enable Limiter Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans Default Description This parameter enables (1) or disables (0) the limiter function of the dynamics processor.
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Description This parameter sets the ratio of the target gain applied by the limiter versus the difference between the limiter threshold and the input signal level. For example, if the limiter ratio is 10 (i.e., 10:1) and the input signal level is 6 dB above the limiter threshold, the limiter applies -5.4 dB of gain.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Description This parameter enables (1) or disables (0) the peak limiter function of the dynamics processor. This parameter and dp_en must be enabled for the peak limiter to function.
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Description This parameter enables (1) or disables (0) the acoustic echo cancellation (AEC) algorithm. aec_noise_fill Enable Noise Fill Argument Argument value Channel Type Virtual Channel Value Type Boolean Read/Write Mode Read/Write Phys Chans Conferencing Mic/Line Input Virt Chans Mono, Stereo Default Description This parameter enables (1) or disables (0) the noise fill algorithm in the AEC.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The index is used to specify the left (1) or right (2) reference channels. If neither the left nor the right channel have references specified, then the AEC is disabled. If only the left channel is specified, then the mono AEC algorithm is used.
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Description This parameter sets the maximum gain (in dB) that can be applied by the AGC. agc_min_gain AGC Minimum Gain Argument Argument value Channel Type Virtual Channel Value Type Floating-Point Read/Write Mode Read/Write Phys Chans Conferencing Mic/Line Input, Sound Reinforcement Mic/Line Input, Analog Telephony Input Virt Chans Mono, Stereo...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Description This parameter sets the amount of delay applied to the audio signal, in samples. The sampling frequency is 48 kHz, which means that a sample is 20.83 microseconds. The maximum delay of 96000 samples is equivalent to 2 seconds.
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fb_filter_bandwidth Feedback Reduction filter Bandwidth Argument Argument value Channel Type Virtual Channel Value Type Floating-Point Read/Write Mode Read/Write Phys Chans Conferencing Mic/Line Input, Sound Reinforcement Mic/Line Input Virt Chans Mono, Stereo System Limits Minimum: 0.03, Maximum: 1.0, Resolution: 0.01 Default User Limits Supported Description...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 fb_filter_reset Reset One Of The Feedback Reduction Filters Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans Indices Description Setting this parameter resets the specified filter in the feedback reduction algorithm.
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fb_safe_mode_atten Safe Mode Attenuation For Feedback Reduction Argument Argument value Channel Type Virtual Channel Value Type Floating-Point Read/Write Mode Read/Write Phys Chans Conferencing Mic/Line Input, Sound Reinforcement Mic/Line Input Virt Chans Mono, Stereo System Limits Minimum: 0.0, Maximum: 100.0, Resolution: 0.1 Default User Limits Supported...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Description This parameter selects the index of the audio source for the corresponding cr_mic_in or sr_mic_in physical channels. The index required for this parameter indicates to which physical channel of the virtual channel this parameter will be applied.
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Argument Phys Chans Virt Chans Values Description This parameter selects the audio source for the corresponding cr_mic_in or sr_mic_in physical channels. The analog type selects the analog microphone audio. The clink_mic type selects one of the ConferenceLink microphone elements. Control of which element is selected is done through the mic_source_index parameter.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 nc_level Noise Cancellation Level Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans System Limits Default User Limits Supported Description This parameter sets the amount of cancellation (in dB) applied by the noise cancellation algorithm.
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sig_gen_sweep_start Signal Generator Sweep Start Frequency Argument Argument value Channel Type Virtual Channel Value Type Floating-Point Read/Write Mode Read/Write Phys Chans Signal Generator Virt Chans Mono System Limits Minimum: 20.0, Maximum: 20000.0, Resolution: 0.1 Default 20.0 User Limits Supported Description When the signal generator’s sig_gen_type is set to sweep, this parameter sets the frequency (in Hz) at which the sweep generator begins.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 sig_gen_sweep_stop Signal Generator Sweep Stop Frequency Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans System Limits Default User Limits Supported Description When the signal generator’s sig_gen_type is set to sweep, the parameter sets the frequency (in Hz) at which the sweep generator stops.
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sig_gen_tone_freq Signal Generator Tone Frequency Argument Argument value Channel Type Virtual Channel Value Type Floating-Point Read/Write Mode Read/Write Phys Chans Signal Generator Virt Chans Mono System Limits Minimum: 20.0, Maximum: 20000.0, Resolution: 0.1 Default 1000.0 User Limits Supported Description This parameter sets the frequency (in Hz) of the sine wave produced by the signal generator when its sig_gen_type is set to tone.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Input Path Parameters cr_ungated_type Select Processing For Ungated Signal Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans Values Description This parameter selects the version of signal to use for the ungated triune signal of the specified virtual channel.
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sr_ungated_type Select Processing For Ungated Signal Argument Argument value Channel Type Virtual Channel Value Type List Read/Write Mode Read/Write Phys Chans Sound Reinforcement Mic/Line Input Virt Chans Mono, Stereo Values rec : Recording sr : Sound Reinforcement line : Line Input (default) bypass : Bypass Description This parameter selects the version of signal to use for the ungated triune signal...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Automixer Parameters am_adapt_thresh Automixer Adaptive Threshold Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans System Limits Default User Limits Supported Description This parameter defines how much louder (in dB) the microphone's signal level must be above its measured noise floor before it is eligible to be considered active.
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am_chairman Automixer Chairman Microphone Argument Argument value Channel Type Virtual Channel Value Type Boolean Read/Write Mode Read/Write Phys Chans Conferencing Mic/Line Input, Sound Reinforcement Mic/Line Input Virt Chans Mono, Stereo Default Description When this parameter is set to 1, the microphone is considered a chairman microphone.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 am_decay_time Automixer Decay Time Argument Channel Type Value Type Read/Write Mode Indices Systems Limits Default User Limits Supported Description This parameter defines how long (in ms) the gain of a gated microphone in the specified automixer group takes to transition between fully open and its off attenuation value when it is time for the microphone to gate off.
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am_gain_sharing Enable Gain-Sharing Automixer Mode Argument Channel Type Value Type Read/Write Mode Indices Default Description This parameter selects gain-sharing mode for the specified automixer group when set to 1. Otherwise, the microphones in the automixer group are in gating mode. Examples Command Response...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Examples Command Response set am_group "Table Mic val am_group "Table Mic 1" 1 1" 1 am_hold_time Automixer Hold Time Argument Channel Type Value Type Read/Write Mode Indices Systems Limits...
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am_nom_limit NOM Limit Argument Argument value Channel Type Global System Value Type Integer Read/Write Mode Read/Write Indices 1-63 : group number System Limits Minimum: 0, Maximum: 128 Default User Limits Supported Description This parameter sets the NOM limit for the microphone with respect to its automixer group.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 am_priority Automixer Microphone Priority Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans System Limits Default User Limits Supported Description This parameter sets the priority of the microphone. A priority of 1 is the highest priority (most favored), while a priority of 4 is the lowest priority (least favored).
am_slope Gain Sharing Automixer Slope Argument Channel Type Value Type Read/Write Mode Indices System Limits Default User Limits Supported Description This parameter defines how much attenuation (in dB) is applied to microphones in the specified automixer group when they don't have the highest level in the group.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Description This parameter gets or sets the value of the analog gpio pin. Writing an input has no effect and returns the current value of the input. The value for this parameter is an integer between analog_gpio_min and analog_gpio_max, inclusive.
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Argument Argument value System Limits Minimum: -2147483648, Maximum: 2147483647 Default User Limits Supported Description This parameter gets or sets the minimum value of the analog gpio pin. This parameter along with analog_gpio_max control how the analog value of the pin is mapped to an integer range.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Argument System Limits Default User Limits Supported Description This parameter gets or sets the value of the digital gpio array. Writing an input has no effect and returns the current value of the input.
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set eth_settings 1 "mode='dhcp'" val eth_settings 1 "mode='dhcp',addr='172.22.2.129',dns='172.22.1.1 172.22.1.2',gw='172.22.2.254',nm='255.255.255.0'" Static IP Example set eth_settings 1 "mode='static',addr='172.22.2.200',dns='172.22.1.1',gw='172.22.2.254',nm='255. 255.255.0'" val eth_settings 1 "mode='static',addr='172.22.2.200',dns='172.22.1.1',gw='172.22.2.254',nm='255. 255.255.0'" Examples Command Response set eth_settings 1 val eth_settings 1 "mode='dhcp'" "mode='dhcp',addr='172. 22.2.129',dns='172.22.1.1 172.22.1.2',gw='172.22.2. 254',nm='255.255.255.0'" set eth_settings 1 val eth_settings 1 "mode='static',addr='192.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Description This parameter selects the method for obtaining the IP address of the ethernet port. eth_mac Get Ethernet MAC Address Argument Channel Type Value Type Read/Write Mode System Limits Description This parameter gets the MAC address for the system's Ethernet port.
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ir_key_held Key Held On IR Remote Argument Channel Type Value Type Read/Write Mode Phys Chans Virt Chans System Limits Description When queried, this parameter returns the keycode value of the last key that was held on the IR remote. As an event, a status message is generated at an interval of approximately 100 ms whenever an key is held on the IR remote.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 ser_flow RS-232 Flow Control Argument Channel Type Value Type Read/Write Mode Values Description This parameter sets the type of flow control that will be used on the RS-232 port. Hardware flow control is recommended for baud rates over 9600 bps.
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dev_firmware_ver Firmware Version Argument Channel Type Value Type Read/Write Mode System Limits Description This parameter returns the device’s firmware version. Examples Command Response get dev_firmware_ver 1 val dev_firmware_ver 1 "1.0.0" dev_ntp_server NTP Server Argument Channel Type Value Type Read/Write Mode System Limits Default Description...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Argument Value Type Read/Write Mode Values Description This parameter returns the status of the system. A value of ok indicates that the system is operating normally. The front-panel LEDs on all the devices will be green in this condition.
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Channel Type Device-Specific System Value Type List Read/Write Mode Read-Only Values c16 : Conferencing 16x16 c12 : Conferencing 12x12 c8 : Conferencing 8x8 sr16 : Sound Reinforcement 16x16 sr12 : Sound Reinforcement 12x12 sr8 : Sound Reinforcement 8x8 Description This parameter returns the type of the device.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Description This parameter returns the voltage (in Volts) of the ConferenceLink power supply. dev_volt_neg_15 -15 V Supply Voltage Argument Channel Type Value Type Read/Write Mode System Limits Description This parameter returns the voltage (in Volts) of the -15 V power supply.
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Argument Argument value Value Type Floating-Point Read/Write Mode Read-Only System Limits Minimum: 0.0, Maximum: 14.8, Resolution: 0.1 Description This parameter returns the voltage (in Volts) of the +15 V power supply. sys_factory_reset Restore System To Factory Settings Argument Argument value Channel Type Global System Value Type...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 sys_reboot Reset The Device Argument Channel Type Value Type Read/Write Mode Description Setting this parameter causes all linked devices to reboot as if a power-cycle has occurred. A - 120...
Designing Audio Conferencing Systems Reprinted from the BICSI AV Design Reference Manual, the following audio conferencing design material is authored by Craig H. Richardson, copyright 2006. The goal of audio conferencing is to enable two geographically separated groups of people, referred to as the local and remote talkers respectively, to communicate as if they are in the same room together with fast interation and allowing both parties to speak and be heard at the same time.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 The challenge in audio conferencing is that the loudspeaker audio is not only heard by the local participants, but it is also heard by the local microphones and, in the absence of an acoustic echo canceller, will be sent back to the remote participants causing the remote participants to hear a delayed echo of their voice.
Microphone Selection And Placement The type of microphones used and their location will have the largest impact on the audio conferencing quality. Microphones translate the acoustic signals from the local talkers into electrical signals that can be processed and sent to the remote participants.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Directional microphones are most often used in conferencing systems due to the rejection of the background noise, reduction of the reverberation, and the rejection of the audio from the loudspeakers. Directional microphones also...
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Designing Audio Conferencing Systems audio signal. When this happens, a noticeable beeping or chipping sound that sounds modulated such as if it were Morse code, will be heard at the remote locations. If this problem is present, the solutions are to move cellular telephones away from the microphones, turn off cellular telephones, or to use microphones that have improved noise immunity to these high frequencies.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 moving microphones closer to the talkers, moving noise sources away from the microphones, lowering the level of the noise, and improving the acoustics in the room to reduce the amount of reverberation. Improving the acoustics in...
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Designing Audio Conferencing Systems Tabletop Microphones In many conferencing applications boundary tabletop microphones are used and mounted at locations around the table as shown in the following figure where one microphone is used for each two participants. All participants that are seated at the table are well within the microphones pick-up ranges as shown in the next figure.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Wireless Microphones Wireless microphones are also commonly used in conferencing applications, particularly for presenters. The advantage of wireless microphones is that they may be used anywhere within the room (depending on whether in-room...
Designing Audio Conferencing Systems installed. With the use of a microphone amplifier and powered loudspeaker, it is a simple matter to have the customer listen to the audio quality and agree that it is acceptable before additional work is performed. This will save costly re-installation work.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Noise Cancellation The ambient noise in the room caused by HVAC, projectors, computers, and even noise external to the room that is picked up by the microphones will reduce the signal to noise ratio at the microphones. This noise will then be...
Designing Audio Conferencing Systems However, if ceiling microphones are swaying due to the air flow from nearby HVAC ducts, noise cancellation may not be able to completely remove that noise. Acoustic Echo Cancellation In audio conferencing applications, acoustic echoes occur because an open-air acoustic path exists between the local loudspeaker and the local microphone.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 around. The following figure illustrates the block diagram of an AEC system and shows the adaptive filter at its center. It is common to refer to the signals associated with an echo canceller as follows: the Near In signal consists of the...
AEC Reference The AEC reference provides the AEC with the information of what signals it should cancel from the room (see the following figure). The echo canceller reference is usually a combination of audio from the remote sites including telephone and video conferencing audio and also any program audio sources. Microphone signals are typically not included in the acoustic echo canceller reference signal.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 200 msec for larger rooms. As shown in the following figure, if the room is lively, the length of an echo path may be longer than expected making the room appear acoustically larger than it is physically.
Designing Audio Conferencing Systems may occur in the data as it is transmitted through the network. It is not uncommon for networks to require a hundred milliseconds or more to transfer audio from one site to the other. Local Room Remote Room Delay Delay...
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 would be the ratio of 10 Log (B/C) which, due to the acoustic echo canceller, should be a larger number than the ERL. Typical values for ERLE are 15 - 25...
left side of the following figure), each local talkers' voice will be processed by the same noise reduction algorithm to remove noise regardless of whether that noise was incident on that particular microphone. Auto Mixer Similarly with respect to the acoustic echo canceller, it is also better to process the signals independently as each microphone has its own acoustic view of the room and sees an acoustic echo that is different from the other microphones.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 If the microphones are muted in the signal chain before the acoustic echo canceller, then while the microphones are muted, the AEC will not be able to adapt as there will be no signal present. Once the microphones are unmuted, the AEC may have to reconverge to any new echo paths.
The most common reason for acoustic echo is that the echo return loss of the room is not high enough to allow the acoustic echo canceller to properly adapt to the remote audio. This is usually solved by reviewing the gain structure and turning down the amplifier and bringing up the signals that make up the echo canceller reference.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Transmit Receive While side-tone is desirable while talking on a handset, it is not desirable in a conferencing application. As the line echo (or side-tone) is mixed together with...
Amplifiers There are two broad classes of amplifiers - low impedance and constant voltage. The low impedance amplifiers are the type of amplifier used in consumer applications and the constant voltage amplifiers are used in larger, professionally installed systems. Low impedance amplifiers are designed to drive audio into low impedance loudspeakers typically with impedances between 4 and 16 ohms.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 the following figure, not only are listener 2 and listener 3 farther away from the loudspeaker than listener 1 and receive less audio due to the inverse square relationship, but they also receive less audio from the loudspeaker due to the inherent 6 dB difference between the off-axis response from the on-axis response of the loudspeaker.
Designing Audio Conferencing Systems Another rule of thumb about loudspeaker positioning with listeners is to distribute the loudspeakers no greater than twice the distance from the ceiling to the listener's ear level. In a conference room with 9 foot high ceilings and seated listeners' ears about 3 ½...
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 following figure. As discussed in an earlier section, the microphones should be placed as close to the local participants as possible to minimize the amount of background noise and reverberation.
Loudspeakers - How Much Power Is Required Once the locations of the loudspeakers have been determined, the next step is to determine how much power is required to drive each loudspeaker to achieve the required level at the listeners. Loudspeakers have a power rating that is expressed in dB SPL @ 1 meter.
Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 device, the reinforcement of the ceiling loudspeakers can be delayed slightly (1 msec for each foot of separation) from the front loudspeakers and can be attenuated by approximately 6 - 10 dB from the level sent to the front of room loudspeakers.
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Designing Audio Conferencing Systems intelligibility. If they do, then the system is set correctly. The reinforced levels should never exceed conversational speech levels (approximately 70 dBA SPL typical at the listener's ear) or the result may become unstable, creating residual echoes to the remote listeners due to low ERL and worse may generate very loud acoustic feedback in the room with loudspeaker audio coupling into the local microphones.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 the reinforcement system - zones twice as far away will typically have 6 dB more level). To support zoning, a multi-channel amplifier must be used so that each loudspeaker zone can receive separate loudspeaker signals.
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Designing Audio Conferencing Systems In a room that has sound-reinforcement with inappropriately high gain settings, there is no longer any such thing as a "side conversation". Everyone in the room will likely be able to hear all conversations, making it impossible to have side comments that are private.
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Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 B - 30...