Page 4
– algorithms that push audio processor performance to new and higher levels. Wheatstone was the first to develop an intelligent, “program density aware” AGC (2007 - Sweet Spot Technology, or SST). We were also the first to employ the science of human psychoacoustics in the design of a multiband limiter (2005, our acclaimed 31‑band limiter).
UPS/Power Conditioning ..................1-4 Analog Audio Input Connections ................1-4 Analog Audio Output Connections .................1-5 Digital Audio Connections ..................1-5 Where to Install the AM-55 ..................1-6 Ratings Encoders ....................1-6 Insert Point (Future Feature) ..................1-6 AC Power Considerations ............1‑6 Rear Panel Connections ............... 1‑7 Audio Inputs ........................1-7...
Page 6
Connecting Directly Without a LAN ................3-5 The AM-55 and Internet Security Concerns ...............3-6 About DHCP and the AM-55 ..................3-6 The AM-55 Network Protocols and Ports Used ............3-6 Using the AM‑55 GUI ..............3‑7 Dynamic Displays Region ...................3-8 Frequency-Domain Graph ..................3-8 Managing the Blue Dots - Tutorial ................3-8...
Page 7
System Menu ......................3-33 Input/Output Settings Change With Preset ............3-33 Send Metering Data Over TCP/IP ..............3-33 System Status ....................3-34 Security .......................3-34 Remote Login ....................3-34 Front Panel .....................3-34 GUI Access .....................3-35 GUI Lock ......................3-35 page Contents – 3 AM-55 / Sep 2015...
Page 8
Audio Terms and Wheatstone Processing ..............A-9 Thump/Rumble/Bottom ....................A-9 Punch/Boom/Tubby/Warm ..................A-10 Mud .........................A-10 Honk ........................A-10 Whack ........................A-10 Fuzzy/Tinny ......................A-11 Sibilance .........................A-11 Treble/Bright/Open ....................A-11 Finally ........................A-12 Appendix C WheatNet‑IP Configuration ............A‑14 Adding AM-55 to The WheatNet-IP System ..............A-14 page Contents – 4 AM-55 / Sep 2015...
Page 9
UPS/Power Conditioning ..................1-4 Analog Audio Input Connections................1-4 Analog Audio Output Connections .................1-5 Digital Audio Connections ..................1-5 Where to Install the AM-55 ..................1-6 Ratings Encoders ....................1-6 Insert Point (Future Feature) ...................1-6 AC Power Considerations ............1-6 Rear Panel Connections ............... 1-7 Audio Inputs .......................1-7...
“sought after” sound no matter what the market size. Like other Wheatstone processors, the AM-55 has been carefully designed to not have a fixed sound of its own – the end user can use the AM-55’s vast pallet of tools to create any desired on-air sound.
AM‑55 and devices imm ediately above and/or below it. WARNING! With very few exceptions, the AM-55 chassis DOES NOT need to be opened in the field. Please be advised that the AM‑55 contains high voltage power supply circuits operating at voltages well above AC line input.
Use ground conductors with the largest possible surface area and keep ground leads as short as possible. The AM-55’s ground reference is its chassis, which should be connected to the station ground. Such a connection is especially important when the AM-55 is operated in a high RF environment because it helps minimize differential voltages between the processor’s chassis and other pieces...
AM-55’s XLR output Pin 1 (ground/shield) also be connected to Pin 3 (“Lo”), noting that this MUST BE DONE at the AM-55’s output connector (see the diagram above).
AM signal. The use of the AM-55 in any location other than the transmitter site is not recommended as the AM-55 was designed to be the very last piece of processing gear prior to the transmitter.
G E N E R A L I N F O R M A T I O N Rear Panel Connections The image below shows the rear panel of the AM-55 and the location of various connectors associated with an installation AM‑55 Rear Panel Connections (left to right)
An overload protected stereo headphone amplifier drives the front panel ¼" stereo headphone output located on the left side of the AM-55’s front panel. The audio source feeding the headphones may be chosen from the AM output or the analog and digital inputs, even if those inputs have not been selected to feed the audio processing chain.
G E N E R A L I N F O R M A T I O N General Purpose Interface (GPIO) The AM-55 is equipped with two General Purpose input (GPI) and output (GPO) ports on the rear RJ-45 connector. The General Purpose connections are optically-isolated from AM-55’s internal circuitry to prevent external ground loops and to prevent dangerous...
GUI’s current preset window. If changes to the preset have been made its name will be displayed in red text instead of green. Once the modi- fied settings have been saved back to the AM-55’s hardware the preset name will again be displayed in green.
Page 20
The total number of presets on the AM-55’s hardware cannot exceed eighty (80). The storage space available for presets on the GUI’s host PC (because of a preset’s tiny file size) is virtually unlimited.
AGC’s five frequency bands. Normal gain reduction values will run somewhere around -6 to -15dB. See Chapter 3 on the multiband AGC for a deeper explanation of its behavior and tuning. page 2 – 2 AM-55 / Sep 2015...
WheatNet‑IP) and sets the gain structure for the analog and digital modes. • Pre-Emphasis – Sets the pre‑emphasis used, depending on your region and application. The options are FLAT, 50us, and NRSC. page 2 – 3 AM-55 / Sep 2015...
Page 25
• Access – Allows you to set a password to lock out the front panel. The front panel has a screen saver which activates after a few minutes of inactivity on the front panel controls. page 2 – 4 AM-55 / Sep 2015...
The first option is input source. To select the input source, highlight “input src” and push the knob in. Turn the knob to select the option you wish to place on air. page 2 – 5 AM-55 / Sep 2015...
Because of the advanced algorithms of the AM‑55, the tradeoff between loud and clean is much easier than in older analog designs or even inadequate or primitive digital processor designs page 2 – 6 AM-55 / Sep 2015...
The front panel sound adjustments are set up so that users can quickly change the most basic settings in the audio processor to “get it” on the air and sounding good. Because we have tied together background controls to make the front panel adjustments easy, you page 2 – 7 AM-55 / Sep 2015...
User presets, adjusted and saved with the GUI software, cannot be modified from the front panel. Any preset may be selected, but only genuine Wheatstone factory presets can be modified using the sound controls on the front panel.
192.168.1.155 should be entered as shown in the PC GUI when setting up the GUI to communicate with the AM-55 just as it is written in this example. The front panel does not allow the user to add “leading zeroes”, but it can be accidently entered into the PC GUI.
A message will tell you if the password is correct or incorrect. It is important that you REMEMBER your password. Only numerical characters can be used in password creation. If you lose your password, please contact Wheatstone Technical Support at +1-252-638-7000 Monday thru Friday (except major US holidays) from 8:30am to 5:30pm Eastern time.
Page 32
Connecting Directly Without a LAN ................3-5 The AM-55 and Internet Security Concerns ...............3-6 About DHCP and the AM-55 ..................3-6 The AM-55 Network Protocols and Ports Used ............3-6 Using the AM-55 GUI ..............3-7 Dynamic Displays Region ...................3-8 Frequency-Domain Graph ..................3-8 Managing the Blue Dots - Tutorial ................3-8...
The AM‑55 GUI allows you to adjust the processor and see, in real time, how it is reacting to the audio being processed. All Wheatstone GUI’s have been carefully designed so that no adjustment is more than two mouse clicks away.
As mentioned previously the AM‑55 has auto‑sensing, Auto‑MDIX Ethernet ports. NOTE: The controlling PC and the AM‑55’s network settings must be configured to place them both on the same subnet! page 3 – 5 AM-55 / Sep 2015...
Subnet and for the Gateway usually suffice for all but the most complex situations. The AM-55 Network Protocols and Ports Used The AM‑55 uses both TCP and UDP protocols to communicate with the remote GUI.
The GUI may be positioned on the host computer’s screen by left‑clicking and holding the “Wheatstone” logo and dragging the GUI to the desired position. In normal “Windows” fashion, the GUI may be minimized on the desktop (taken off the screen) and/or closed by way of the familiar controls at the extreme top right.
Managing the Blue Dots – Tutorial We’ve worked very hard on the design of the Wheatstone graphical user interface to make it intuitive, friendly, and easy to navigate and interpret, in spite of how many controls the user has access to.
Page 40
Proportional Drag – Allows the dragging of adjustment dots to create slopes anchored if desired to a single orange set point. Flat Drag – Allows the dragging of dots together in a “flat” orientation. page 3 – 9 AM-55 / Sep 2015...
A small green indicator at the left end of each button indicates if any signal processing within that block is active. Left‑clicking a button opens the associated control panel to gain access to the controls for that block of signal‑processing page 3 – 10 AM-55 / Sep 2015...
Analog indicator is green if there is a signal present on both left and right channels and it is higher than ‑24dBu. The AES indicator turns green when there is a valid AES signal present at the digital input and it is above ‑42dBFS. page 3 – 11 AM-55 / Sep 2015...
This action reduces the peak to average ratio and enables an increase in apparent loudness with minimal audible detriment. We do this because processing the audio is greatly simplified if the waveforms are symmetrical. page 3 – 12 AM-55 / Sep 2015...
CLIPPING depth of the processor. The right side of the lower portion of the GUI shows the relative Positive and Negotive modulation, as well as the TX1 and TX2 output levels. page 3 – 13 AM-55 / Sep 2015...
“Q,” of the equalizer section. EQ Enable This is the master Equalizer In/Out button. When the Enable box is checked the equalizer section is “IN”. page 3 – 15 AM-55 / Sep 2015...
We believe that the amount of control in our AM‑55 GUI allows the user to virtually set the AM‑55 to whatever sonic texture they can think of, eliminating the need for an outboard processor to emulate the same. page 3 – 16 AM-55 / Sep 2015...
Page 48
STL to prevent overshoot. Again, if you feel the need to use a pre‑processor in either of these situations, adjustments to the AM‑55 should be made in concert with the suggestions above. page 3 – 17 AM-55 / Sep 2015...
Less drive creates a more “gentle” on air sound which then has less capability to bring up low passages. The range of this control is ‑12.0dB to +6.0dB. page 3 – 18 AM-55 / Sep 2015...
Band 4 while all other bands remain “flat”. Such a setting is useful in formats such as Classical and Jazz that typically would not enjoy the automatic spectral balance “correction” that more processed formats usually prefer. page 3 – 19 AM-55 / Sep 2015...
If you were, to say, select Comp Atk (compressor attack), you would see the left scale change to show the timing values in milliseconds (ms) of the compressor as shown below. page 3 – 20 AM-55 / Sep 2015...
Page 52
Band 5’s gain reduction value is, at the moment, very similar to Band 4. Compare that to the example below where Band3 has more compression than leveller control and Band 4 is deeper into gain reduction than Band 5. page 3 – 21 AM-55 / Sep 2015...
Leveller because of its longer attack time. The compressor’s purpose is to handle medium term peaks only, and by doing so it completely frees the AGC from having to worry about controlling them. page 3 – 22 AM-55 / Sep 2015...
“hear” what the unmuted bands sound like. Care should be taken when using this feature since it will affect the audio on the air. Muting bands will unmask distortion from the other bands and sometimes you may “forget” you’ve muted a band! page 3 – 23 AM-55 / Sep 2015...
Drives the level into the five band limiter. It’s important to remember that the AM‑55 needs only a few dB of limiting to be loud yet amazingly clean! The drive control is +/‑ 12dB with 0dB being default. page 3 – 24 AM-55 / Sep 2015...
The Tight filter shape keeps virtually all bass harmonics out of the main mix. It is also the lightest sounding of the three and the bass has a very controlled texture. page 3 – 25 AM-55 / Sep 2015...
Samples or Seconds manually by typing in the value you require by left clicking in the appropriate box, entering the value and pressing ENTER. The diversity delay will then shift to that value. page 3 – 26 AM-55 / Sep 2015...
The Release time control determines how quickly the limiter will return to 0dB resting value once audio has fallen below the limiter threshold. Faster release times will yield a louder sound while slower times will yield a smoother sound at the expense of some loudness. page 3 – 27 AM-55 / Sep 2015...
The Pos. Peak Threshold control governs all outputs, so care should be taken when feeding your main and backup transmitters that both will be capable of the amount of positive modulation dialed in. page 3 – 28 AM-55 / Sep 2015...
120% on positive peaks. You now have the proper ratio of positive to negative peaks set up, along with 5% headroom to adjust for loudness. Polarity Invert Polarity Invert check box switches output’s absolute polarity. page 3 – 29 AM-55 / Sep 2015...
Level control and the TX 1 or TX 2 output (as appropriate) until approximately 60% modulation is indicated on the station’s modulation monitor. Ensure that the LF Tilt EQ L (level) controls are set at 0dB. page 3 – 30 AM-55 / Sep 2015...
When bandwidth restrictions cause modulation overshoot, the best way to minimize it is to (1) reduce the bandwidth of the signal entering the transmission system, (2) reduce the rise time of the waveforms exiting the audio processor, or (3) a combination of both. page 3 – 31 AM-55 / Sep 2015...
Page 63
C, alternately adjust the HF Corr EQ “F” (Fre‑ quency), “Q” (Bandwidth) and “L” (Level) controls in order to achieve the flattest top and bottom waveforms, and reduce overshoot on the waveform’s leading edge. page 3 – 32 AM-55 / Sep 2015...
• Digital Output Level • Tilt Frequency Adjustments Wheatstone recommends that this option remain unchecked unless you have a need to change any of the above settings when a new preset is taken. When this option is NOT selected, the parameters listed above remain static between presets and only the sound adjustments are changed.
If the access code has been lost or forgot‑ ten you need to contact our technical support at (252) 638‑7000 or email us at: techsup‑ port@wheatstone.com. page 3 – 35 AM-55 / Sep 2015...
Preset Library by clicking on the Library button in the GUI. Once the list of presets is open, the ones actually stored within the processor hardware itself will be visible in the left pane. page 3 – 36 AM-55 / Sep 2015...
(Preset #) up or down. Note that it is possible to save the present settings in over an existing and unlocked preset and doing so erases the previous preset’s contents. Factory presets are protected from being inadvertently overwritten. page 3 – 37 AM-55 / Sep 2015...
TRS jack for headphone use. The volume control for the head‑ phone output is located on the lower right side of the GUI. To adjust the headphone volume slide the fader right to increase volume and left to decrease it. page 3 – 38 AM-55 / Sep 2015...
A M - 5 5 G U I Title Bar Region Along the top edge of the AM‑55 GUI screen (in line with the Wheatstone AM55 product label to the left, and the Windows About, Minimize, and Exit icons to the right) are indicators and controls for the management of devices and presets.
• Offline – the double‑clicked preset brings that preset onto the main control and display screen for perusa l/editing. Any data entry / control which involves activity within the main graph will still operate upon the preset, but not on the AM‑55’s audio. page 3 – 40 AM-55 / Sep 2015...
Devices... – Opens the Devices dialog box. Allows the creation, editing, selection, and deleting of Wheatstone processors connected to your system. On‑Line Mode... – Toggles between ONLINE and OFFLINE modes. This is the state the GUI will assume the next time it is started. This state is also remembered when the GUI is closed –...
Page 73
AM‑55 (cycle its power). The AM‑55 is extremely easy to update when new firmware becomes available from Wheatstone. The update file is a “.RBN” which is packaged with a new GUI. Before performing updates to the AM‑55 make sure an auxiliary processor is available for when AM‑55...
AM‑55. This can be done by removing and restoring power or by sending the reboot command from the GUI. After the AM‑55 reboots the new RBN code will be running on the motherboard. If you have any questions about an update, feel free to contact Wheatstone Technical Support at techsupport@wheatstone.com. Presets Menu Items The Presets menu tree may be accessed by right clicking anywhere on the main AM‑55 Control Panel.
Input Gain Adjustment Ranges Gain Range: +/-12dB Gain Adjustment Resolution: 0.5dB Gain Calibration: A gain control setting of 0.0 aligns an external 0dBFS signal with the AM-55’s 0dBFS internal reference Input Failover Type: Automatic Analog Fail Cause: Audio level below -42dBFS (fixed)
Page 78
Super Low to Low Band: 50‑130Hz Low to Low Mid Band: 220‑540Hz Low Mid Band to High Mid Band: 800‑2400Hz High Mid Band to High Band: 3500Hz‑7500Hz Band Output Trims: +/‑ 6dB page A – 4 AM-55 / Sep 2015...
Page 79
Nominal Operating Level: -20dBFS digital Total Harmonic Distortion: <0.1%, 20Hz to 20kHz * Intermodulation Distortion: <0.1% SMTPE * Signal to Noise Ratio: >80dB * Signal Chain Internal Dynamic Range: >144dB page A – 5 AM-55 / Sep 2015 AM-55 / Jan 2018...
Page 80
PC directly to the AM‑55. Software Remote Control Supplied Windows® AM‑55 GUI software affords control of all system and processing parameters via a 100BaseT Ethernet interface. page A – 6 AM-55 / Sep 2015...
Page 81
A P P E N D I C E S Appendix B Contents Interpreting Common Audio Processing Terms ......A-8 Background ........................A-8 Audio Terms and Wheatstone Processing ..............A-9 Thump/Rumble/Bottom ...................A-9 Punch/Boom/Tubby/Warm ..................A-10 Mud ........................A-10 Honk ........................A-10 Whack ........................A-10 Fuzzy/Tinny ......................A-11 Sibilance .........................A-11 Treble/Bright/Open ....................A-11...
“thump” you want will be the “thump” you get and not “tubby.” Please note that some of the controls mentioned on the following pages may not be available on the AM-55. The discussion is generic to a wide variety of Wheatstone processor models.
Many times such systems even have their own complex bass enhancement features. The AM-55 is equipped with a very specialized bass clipper system. This system is an intelligent clipper that samples the bass frequency relationship between bands 1 and 2 and is able to make changes to the audio based on user settings in the five band section as well as the five band limiter.
Leveller or Compressor release times in Band 3. Another trick is to slow down the attack time of the Band 3 leveller which will allow the Band 3 compressor to be more active. This will enhance “whack.” page A – 10 AM-55 / Sep 2015...
“esses.” When excessive sibilance is an issue and there is no microphone processor to control it, lowering the AM-55’s Band 4 to Band 5 crossover setting and/or using a slightly faster attack time on the Band 5 Leveller/Compressor can help.
Fortunately the AM-55 is much more forgiving in this regard and most users have an easier time being loud with the AM-55 while still being quite clean and open. Operating the Leveller...
Page 87
A P P E N D I C E S Appendix C Contents WheatNet-IP Configuration ............A-14 Adding AM-55 to The WheatNet-IP System .............A-14 page A – 13 AM-55 / Sep 2015...
WheatNet-IP Configuration Along with Digital AES3 and Analog inputs AM‑55 is also equipped with WheatNet‑IP (WNIP), the Audio Over Internet Protocol (AoIP) used in our Wheatstone BLADE and IP audio network control surface environment. WheatNet‑IP permits AM‑55’s input audio and its output to be carried over the same standard CAT5 Ethernet cable as that used for remotely controlling AM‑55.
Page 89
WheatNet‑IP BLADE3 Audio Over IP Network manual. Assistance in configuring AM‑55 for WheatNet‑IP may be obtained by giving us a call at 252‑638‑7000 or by emailing techsupport@wheatstone.com. page A – 15 AM-55 / Sep 2015 AM-55 / Apr 2016...
Need help?
Do you have a question about the AM-55 and is the answer not in the manual?
Questions and answers