Understanding Virtual Channels; Soundstructure Studio - Polycom SoundStructure C16 Design Manual

Understanding 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.
SoundStructure Studio Virtual Channels
Control Physical
System Channel
Virtual channels are created by specifying a virtual channel name, one or more physical channels, and a
type of virtual channel. Once defined, the virtual channel name becomes the primary way of referring to that
particular input or output instead of using the physical channel number. For example, an A/V designer
defines the virtual channel that is connected to input physical channel 9 as "Podium mic," as shown in the
following figure. From then on, any settings that need adjusting on that input are adjusted by controlling the
virtual channel "Podium mic". The association between the virtual channel and the underlying physical
channel or channels means that you can think of virtual channels as describing how the system is wired.
Virtual Channel Naming
Input 9
Note: Naming Virtual Channels
The virtual channel name is case-sensitive and needs to have the quotes around
the text. "Podium mic", "Podium Mic", and "PODIUM mic" would represent different
virtual channels.
The main benefit of virtual channels is that once a SoundStructure design is created and the virtual channels
have been defined, it is possible to change the particular physical input or output used by moving the
physical connection on the rear-panel of the SoundStructure device and redefining the virtual channel to use
the new physical input or output that is used. Because any control system code must use the virtual channel
name, the control source code does not have to change even if the actual wiring of the physical inputs or
outputs change. By using virtual channel names the controller code controls (for 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". It would not matter to the control system if on one
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