Polycom C12 - Manual

Introduction 1 - 3 • 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 ...

2 - 1 2 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” st...

SoundStructure Product Family 2 - 3 echo cancellation while the SR-series products do not include acoustic echo cancellation. The processing capabilities will be described in the following sections. OBAM™ - One Big Audio Matrix One of the significant advancements in the SoundStructure products is th...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2 - 4 • It is easier to work with the system because all the input signals feed into the single matrix and all the outputs are fed from the single matrix • The a/v designer can be more creative as there are no limitations on how sign...

SoundStructure Product Family 2 - 5 SoundStructure C-series Products The SoundStructure C16, C12, and C8 devices are designed for audio conferencing applications where groups of people want to communicate to other individuals or groups such as in a typical room shown in the following figure. The Sou...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2 - 6 Each SoundStructure C-series device may be used with traditional analog microphones, with Polycom's HDX digital microphone arrays 1 . For detailed information on using the Polycom HDX digital microphone arrays, see Chapter 6.Ty...

SoundStructure Product Family 2 - 7 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 s...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2 - 8 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 e...

SoundStructure Product Family 2 - 9 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 pr...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2 - 10 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. Recording/Ungated Version The recording version of ...

SoundStructure Product Family 2 - 11 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. Recording/Ungated - Line Input The recording - line input version...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2 - 12 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. All three version...

SoundStructure Product Family 2 - 13 The following figure highlights how to interpret the matrix crosspoints in the matrix. 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 o...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2 - 14 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 ...

SoundStructure Product Family 2 - 15 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 A...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2 - 16 In order for the local acoustic echo canceller to cancel the acoustic echo of the remote participants, it must have an echo canceller reference defined. The echo canceller reference includes all the signals from the remote sit...

SoundStructure Product Family 2 - 17 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. The SoundStructure SR12 can not be used to add additional conf...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2 - 18 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 toge...

SoundStructure Product Family 2 - 19 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 ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2 - 20 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...

SoundStructure Product Family 2 - 21 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 These three different versions of the input sig...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2 - 22 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. Sound Reinforcement Version The s...

SoundStructure Product Family 2 - 23 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 sign...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2 - 24 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 ca...

SoundStructure Product Family 2 - 25 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 ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2 - 26 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. 1 2 N 1 2 N Telco Processing...

SoundStructure Product Family 2 - 27 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 figu...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 2 - 28 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...

SoundStructure Product Family 2 - 29 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.). Typically, the telephony cards will be used in the C-series devices for audio c...

3 - 1 3 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 3 - 2 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 requi...

SoundStructure Design Concepts 3 - 3 The physical input channels and the physical output channels will be numbered from 1 to the maximum number of physical channels in a system. As described below, this approach is an enhancement of how traditional audio signals are labeled and how their signals are...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 3 - 4 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. When multiple devices are linked together via OBAM, the SoundStr...

SoundStructure Design Concepts 3 - 5 continue for additional devices. This connection strategy, shown in the following figures, simplifies the sequential physical channel numbering as described next. Once multiple devices are OBAM linked, it is easy to determine the system's input and output physica...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 3 - 6 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 ex...

SoundStructure Design Concepts 3 - 7 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 becom...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 3 - 8 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 d...

SoundStructure Design Concepts 3 - 9 The organization of the devices in this example would make it confusing to properly terminate inputs and outputs to the desired physical inputs and outputs. Any OBAM linking scheme other than the out-to-in, top-to-bottom system, is not recommended as it will like...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 3 - 10 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 st...

SoundStructure Design Concepts 3 - 11 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 contro...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 3 - 12 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 Physica...

SoundStructure Design Concepts 3 - 13 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. Commands s...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 3 - 14 As an example of using physical channels, virtual channels, and virtual channel groups, consider a SoundStructure C12 device where there are ten microphone inputs, a telephony interface, and a Polycom HDX system as shown in th...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 3 - 16 Virtual Channel Group Summar y 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. It is possible to have more than on...

SoundStructure Design Concepts 3 - 17 Physical Logic Pins The physical logic pins and their labeling is shown in the following figure. 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 SoundStruc...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 3 - 18 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 -...

SoundStructure Design Concepts 3 - 19 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. Analog Gain Input The analog gai...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 3 - 20 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 3 - 21 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 acknowle...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 3 - 22 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...

SoundStructure Design Concepts 3 - 23 IR Receiver Virtual Channel The IR receiver input on the SoundStructure device will respond with acknowledgments when a valid IR signal is received. The first step towards using the IR receiver is to define the IR receiver virtual channel. This may be done with ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 4 - 2 • Follow the on-screen steps to specify the output signals • Select the SoundStructure devices to be used for the design • Create the configuration and optionally upload to the SoundStructure devices These steps are described i...

Creating Designs with SoundStructure Studio 4 - 3 SoundStructure Studio The first step to creating a SoundStructure design is to launch the SoundStructure Studio application. If the SoundStructure Studio software is not already installed on the local PC, it may be installed from the CD that was incl...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 4 - 4 of input (Ceiling, Lectern, …) and the quantity of the input and then click “Add”. The label of the input signal will become the virtual channel name of that input signal. A signal generator will be added by default to all proj...

Creating Designs with SoundStructure Studio 4 - 5 A typical system is shown in the next figure where a stereo program audio source, eight table microphones, a wireless microphone, a telephony input, and a Polycom HDX video codec have been selected. The graphic icon next to the signal name in the Cha...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 4 - 6 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. The outputs includ...

Creating Designs with SoundStructure Studio 4 - 7 Step 3 - Device Selection In Step 3, the devices that will be used with the design are selected as shown in the following figure. By default, SoundStructure Studio will display the equipment with the minimum list price, although it is possible to man...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 4 - 8 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 interfac...

Creating Designs with SoundStructure Studio 4 - 9 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 h...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 4 - 10 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 s...

Creating Designs with SoundStructure Studio 4 - 11 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 remind...

5 - 1 5 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 us...

Customizing SoundStructure Designs 5 - 3 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 4 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. With the E...

Customizing SoundStructure Designs 5 - 5 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....

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 6 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 Channel...

Customizing SoundStructure Designs 5 - 7 button as shown in the following figure. 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. Designs may be adjusted to add more inputs or outputs...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 8 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 C...

Customizing SoundStructure Designs 5 - 9 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 rig...

Customizing SoundStructure Designs 5 - 11 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” will...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 12 there are no dashed lines around the gain for the “Zone 1 Mics” group. If a parameter for all members of a virtual channel group is individually changed to the same value, say one channel at a time until all channels have the ...

Customizing SoundStructure Designs 5 - 13 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 ite...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 14 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 mini...

Customizing SoundStructure Designs 5 - 15 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 in...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 16 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 followin...

Customizing SoundStructure Designs 5 - 17 any processing and the level_post is after the processing. Conference Link Channels The Conference Link channels for HDX Program Audio in and HDX Video Call In have a level_pre and level_post as shown on the following figure. The HDX PSTN In and HDX UI Audio...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 18 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 ...

Customizing SoundStructure Designs 5 - 19 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 continuo...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 20 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 us...

Customizing SoundStructure Designs 5 - 21 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 m...

Customizing SoundStructure Designs 5 - 23 where a program audio source can be processed with parametric equalization, automatic gain control, dynamics processing, fader, delay, and input mute. The Sound Reinforcement path is selected by default for microphone audio because that processing path inclu...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 24 Delay Type When the Sound Reinforcement ungated type is selected, there are two delay options that are available on the Sound Reinforcement signal path - normal and low delay . The normal delay type for the Sound Reinforcement...

Customizing SoundStructure Designs 5 - 25 following figure. 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. The AEC and noise cance...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 26 sound reinforcement paths. Delay Compensation The delay compensation control adds a fixed delay to the line input and bypass signal processing paths to keep the different version of the input pro- cessing time aligned through ...

Customizing SoundStructure Designs 5 - 27 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 28 gain of 64 dB will be added in the digital domain. Equalization The equalization processing that is available for each input consists of dedicated • Low Pass filter • High Pass filter • Low Shelf filter • High Shelf filter • 1...

Customizing SoundStructure Designs 5 - 29 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, t...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 30 • Notch filter • Allpass filter 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 t...

Customizing SoundStructure Designs 5 - 31 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 attenuat...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 32 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 lo...

Customizing SoundStructure Designs 5 - 33 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 mon...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 34 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. Once the conferencing ungated type is selected in the channels pa...

Customizing SoundStructure Designs 5 - 35 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 distan...

Customizing SoundStructure Designs 5 - 37 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 thr...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 38 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...

Customizing SoundStructure Designs 5 - 39 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 t...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 40 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. Gating Automixer Parameters NOM Limit NOM Limit specifie...

Customizing SoundStructure Designs 5 - 41 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 ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 42 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. Priority T...

Customizing SoundStructure Designs 5 - 43 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 t...

Customizing SoundStructure Designs 5 - 45 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 46 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 ...

Customizing SoundStructure Designs 5 - 47 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 d...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 48 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 chos...

Customizing SoundStructure Designs 5 - 49 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 ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 50 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 proc...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 52 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. The...

Customizing SoundStructure Designs 5 - 53 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 54 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 increm...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 56 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 O...

Customizing SoundStructure Designs 5 - 57 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 ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 58 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...

Customizing SoundStructure Designs 5 - 59 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 ch...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 60 path on the SR-series), light blue indicates the sound reinforcement path, and white indicates the ungated/recording path. Telephony Channels To use a telephone interface, either the SoundStructure TEL1 or TEL2 must be include...

Customizing SoundStructure Designs 5 - 61 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. Adj...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 62 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 nex...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 64 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.The cut off frequency can be ...

Customizing SoundStructure Designs 5 - 65 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 th...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 66 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 dia...

Customizing SoundStructure Designs 5 - 67 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 SoundStru...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 5 - 68 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 telep...

6 - 1 6 Connecting Over Conference Link2 This chapter describes how the Conference Link2 interface can be used to easily interface with other Polycom equipment including the Polycom HDX video conferencing system.While there are two Conference Link2 interfaces on a SoundStructure device that permit t...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 6 - 2 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 con...

Connecting Over Conference Link2 6 - 3 The Conference Link2 interconnect allows for the transmission and reception of multiple digital audio signals between the two devices as shown in the fol- lowing figures. These signals will be described in the following sections. Designing With The Polycom HDX ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 6 - 4 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. If a particular input chan...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 6 - 6 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. ...

Connecting Over Conference Link2 6 - 7 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 f...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 6 - 8 The output processing on SoundStructure that is available for these output channels is shown in the following figure. All signals have the same process- ing that includes dynamics, parametric equalization, fader, delay, and mut...

Connecting Over Conference Link2 6 - 9 channel, the SoundStructure “Program Audio” signal is routed to the “HDX Line Mix Out” channel, and the SoundStructure “Mics” group is routed to the “HDX Stereo Mics Out” channel. Mute Control If the mute state changes on the SoundStructure system, the Polycom ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 6 - 10 or set mute “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 mu...

Connecting Over Conference Link2 6 - 11 There is tremendous design flexibility by mapping the HDX Mute command to affect the “Mics” virtual channel or virtual channel group. If there is no “Mics” virtual channel or virtual channel group defined, then no audio paths will be muted when the end user mu...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 6 - 12 It is also possible to limit the minimum and maximum user gain settings via SoundStructure Studio software by using the min and max gain limits on the fader control. This can be done graphically on the channels page as shown i...

Connecting Over Conference Link2 6 - 13 As shown in the following figure, the three microphone elements are labeled as A, B, and C within SoundStructure Studio software environment. The ceiling microphone arrays have an orientation dot on the band that indicates element A. The orientation of the mic...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 6 - 14 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 mic...

Connecting Over Conference Link2 6 - 15 device. If the version of firmware on the microphones is older than the version of firmware included with the SoundStructure firmware, the microphones will be automatically updated with the version firmware from SoundStructure.Version 24 of the microphone firm...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 6 - 16 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...

Connecting Over Conference Link2 6 - 17 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 pr...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 6 - 18 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. In the final step, offline operation will ...

Connecting Over Conference Link2 6 - 19 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 6 - 20 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...

Connecting Over Conference Link2 6 - 21 Digital Microphone Array Numbering Examples of the microphone connections and their numbering within Sound- Structure are shown in the following figure. PIN 2: TXDPIN 3: RXDPIN 5: GROUNDPIN 7: CTSPIN 8: RTS LAN C-LINK2 OBAM IR RS-232 REMOTE CONTROL 2 IN OUT 1 ...

Connecting Over Conference Link2 6 - 23 Installation Options 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 m...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 6 - 24 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 con...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 6 - 26 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 d...

Connecting Over Conference Link2 6 - 27 The digital microphones should be connected to the right rear CLink2 port and the HDX video codec should be connected to the left CLink2 port as shown in the following figure. PIN 2: TXDPIN 3: RXDPIN 5: GROUNDPIN 7: CTSPIN 8: RTS LAN C-LINK2 OBAM IR RS-232 REM...

7 - 1 7 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 syst...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 7 - 2 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...

Installing SoundStructure Devices 7 - 3 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 7 - 4 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. SoundStructure system: SoundStructure System ...

Installing SoundStructure Devices 7 - 5 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 Sound...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 7 - 6 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 req...

Installing SoundStructure Devices 7 - 7 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 ha...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 7 - 8 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. Click on the “...” butt...

Installing SoundStructure Devices 7 - 9 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 conf...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 7 - 10 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...

Installing SoundStructure Devices 7 - 11 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 le...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 7 - 12 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 t...

Installing SoundStructure Devices 7 - 13 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. Accept...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 7 - 14 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. The room gain measurements and guideli...

Installing SoundStructure Devices 7 - 15 Phone In Channel Phone Out Channel Fader Tone Generator Delay A/D Converter Analog Gain D/A Converter Analog Gain Input from PSTN Line Output to PSTN Line From T elco to Matrix To Te lc o from Matrix Noise Cancellation Parametric Equalization Dynamnics Proces...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 7 - 16 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 SoundSt...

Installing SoundStructure Devices 7 - 17 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 ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 7 - 18 2. Set the analog output gain on the amplifier output channel to be either +4, 0, or -10 depending on the nominal signal level required by the audio amplifier. Amplifiers with RCA inputs will require a -10dB setting, most syst...

Installing SoundStructure Devices 7 - 19 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. Adjust the audio amplifier vo...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 7 - 20 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. Presets Once any settings of the So...

Installing SoundStructure Devices 7 - 21 Preset Operation SoundStructure devices store presets in non-volatile memory to ensure the preset settings are not lost upon power cycling. When presets are executed, all the parameter settings for the preset are copied into the current device settings which ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 7 - 22 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 execut...

Installing SoundStructure Devices 7 - 23 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 chan...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 7 - 24 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 store...

Installing SoundStructure Devices 7 - 25 • 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...

Installing SoundStructure Devices 7 - 27 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 7 - 28 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 the...

Installing SoundStructure Devices 7 - 29 Removing Presets Presets may be removed from the system by left clicking on the preset and then clicking Remove Preset . If the power-on preset is removed and the system rebooted, the system will boot into the current settings if they have been stored in the ...

8 - 1 8 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, con...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 8 - 2 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 discover...

Network Management 8 - 3 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 8 - 4 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='255.255.255.0',dns='66.82.134.56'” where the 1 repre...

Network Management 8 - 5 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 t...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 8 - 6 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 ses...

Network Management 8 - 7 Depending on the network router configurations in the network, SoundStruc- ture device discovery may not work across different subnets. However it is still possible to remotely configure SoundStructure devices if the IP address of the device is known as the IP address may be...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 8 - 8 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...

Network Management 8 - 9 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.

9 - 1 9 Advanced Applications This chapter describes several applications of the SoundStructure products and the steps required to create these applications. These applications include conferencing applications. • 1 microphone with mono video conferencing • 4 digital microphone arrays and a SoundSta...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 2 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 softwa...

Advanced Applications 9 - 3 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 SoundStru...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 4 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 6 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. The signal generato...

Advanced Applications 9 - 7 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 settin...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 8 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 ...

Advanced Applications 9 - 9 4 digital Array Microphones And A SoundStation VTX1000 This example creates a typical audio conferencing system with four digital microphone arrays, mono program audio, a SoundStation VTX1000, and a single audio amplifier zone. In this application the VTX1000 will be the ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 10 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. SoundStructure C16 HDX Microphones Program Aud...

Advanced Applications 9 - 11 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 sour...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 12 Step 2 - Select Outputs Select a mono amplifier as the output source. The VTX1000 output will be automatically defined when the VTX1000 input is defined. Step 3 - Select Devices Select the equipment required to create this des...

Advanced Applications 9 - 13 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 followi...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 14 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 th...

Advanced Applications 9 - 15 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 ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 18 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 ...

Advanced Applications 9 - 19 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 adj...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 20 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. The room may look...

Advanced Applications 9 - 21 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 mon...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 22 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 ...

Advanced Applications 9 - 23 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 28 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 receive...

Advanced Applications 9 - 29 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 st...

Advanced Applications 9 - 31 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 in...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 32 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 fig...

Advanced Applications 9 - 33 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”.

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 34 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 ot...

Advanced Applications 9 - 35 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.

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 36 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 on other physical inputs or outputs, simply drag the ch...

Advanced Applications 9 - 37 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 38 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.

Advanced Applications 9 - 39 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 exampl...

Advanced Applications 9 - 41 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.B...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 44 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. Only the output to th...

Advanced Applications 9 - 45 By default the AEC reference has been set to the stereo virtual channel “Ampli- fier” and is then shown to be in stereo mode.

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 46 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- nels on other physical inputs or outputs, simply drag...

Advanced Applications 9 - 47 8 Mics With The Polycom HDX Video Conferencing System 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 syst...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 48 Step 1 - Select Inputs Select eight table microphones and a Polycom HDX video conferencing sys- tem. Notice that when the HDX system is selected, there are multiple audio streams that will be transmitted from the HDX to the So...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 50 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 ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 52 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 other physical inputs or outputs, simply drag the channels ...

Advanced Applications 9 - 53 When connected to the Polycom HDX system, the microphones on the Sound- Structure by muting the microphones on the Polycom HDX system. As described in Chapter 6, the HDX will send a mute command to the “Mics” group whenever the HDX receives a command to mute via the HDX ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 54 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 microp...

Advanced Applications 9 - 55 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 se...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 58 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” group as shown in the f...

Advanced Applications 9 - 59 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,...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 60 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 assig...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 62 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 “WirelessR...

Advanced Applications 9 - 63 The “RemoteAudio” submix will also be routed to the different amplifier zones and remote telephone participants.

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 64 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 on other physical inputs or outputs, simply drag the ch...

Advanced Applications 9 - 65 The reinforcement of the wireless microphone may be disabled by muting the reinforced crosspoints as shown next. set matrix_mute “Wireless Mic” “Amplifier 1” 1set matrix_mute “Wireless Mic” “Amplifier 2” 1set matrix_mute “Wireless Mic” “Amplifier 3” 1 The reinforcement o...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 66 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 si...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 68 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. Ste...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 72 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. To create a zoned reinforcement sy...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 74 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 show...

Advanced Applications 9 - 75 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. The wireless mic...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 76 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. Controlling The System The system ca...

Advanced Applications 9 - 77 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” 1inc fader “Phone In” 1 to increase the gain on the faders - making the “VSX8000 In” and “Phone In” chan...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 78 Room combining application with two rooms This example shows how to use the SoundStructure products for a room com- bining application. This example assumes there are two rooms, each with a PSTN line, a program audio feed, a l...

Advanced Applications 9 - 79 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 Room 1 Room 2 Display ABC ABC ABC ABC ABC ABC...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 80 • Both telephone lines are routed to the loudspeakers • Both program audio sources are routed to the loudspeakers • All microphones are in the same automixer • The telephones are routed to each other • There is no reinforcemen...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 82 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 84 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 inclu...

Advanced Applications 9 - 85 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 pa...

Advanced Applications 9 - 87 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 audi...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 88 The automixer settings for the Room 1 mics is shown in the following figure after the Room 2 microphones have been removed.

Advanced Applications 9 - 89 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 th...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 9 - 90 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 ...

Advanced Applications 9 - 91 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. The amplifier ...

10 - 1 10 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. ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 10 - 2 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.Check that the wiring for...

TroubleShooting 10 - 3 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” is routed to ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 10 - 4 Echo Troubleshooting Many echo problems can be traced to: 1. Check loop-back echo. A matrix cross-point may have been inadvertently unmuted, causing a direct replica of the audio to be heard remotely. 2. AEC Reference is setup...

TroubleShooting 10 - 5 Mute all the microphones except for one and on the unmuted microphone, check the value of the AEC reference. In the following figure the AEC refer- ence is set to the “Amplifier” stereo virtual channel. Next, check the matrix to ensure the “Amplifier” virtual channel includes ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 10 - 6 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. If the reference is set properly an...

TroubleShooting 10 - 7 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 atte...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 10 - 8 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 Rem...

TroubleShooting 10 - 9 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 10 - 10 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. What Does The Error “no virtual chan...

TroubleShooting 10 - 11 set mute “Mics” 1 and set mute “Mics” 0 to mute and unmute, respectively the microphones. This command should generate a series of command status messages that report the mute state of the individual virtual channels that are in the virtual channel group as well as an overall...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 10 - 12 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 b...

TroubleShooting 10 - 13 What Is Flow Control And How Does It Work? Hardware flow control on the SoundStructure device requires two additional handshaking signals, CTS and RTS, in the RS-232 cable to ensure data is received before additional data is sent. This prevents the serial port from drop- ping...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 10 - 14 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. How Do I Connect Multiple HDX’s T...

TroubleShooting 10 - 15 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 SoundStruct...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 10 - 16 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 ...

TroubleShooting 10 - 17 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 10 - 18 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...

11 - 1 11 Specifications Technical Specifications Dimensions • 19" (483 mm) W x 13.5" (343 mm) L x 1.75" (45 mm) H (one rack unit) Weight • 12 lbs. (5.5 kg) dry, 14 lbs. (6.4 kg) shipping Connectors • RS-232: DB9F • OBAM In/Out: IEEE 1394B • CLINK2: RJ45 • LAN: RJ45 • Control/Status: DB2...

11 - 2 Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Thermal • Thermal Dissipation (Btu/hr): 266 Btu/hr (C16), 230 Btu/hr (C12), 215 Btu/hr (SR12), 200 Btu/hr (C8) • Operating temperature 0 - 40° C (104° F) Inputs • Phantom power: 48 V DC through 6.8 kOhm series resistor per leg...

11 - 4 Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Pin Out Summar y PSTN Cable To build a custom telephone cable, use 26AWG twisted-pair cable using the wiring connections shown in the following figure. Warning Drawings and part numbers are provided for reference only. Other t...

Specifications 11 - 5 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 ...

11 - 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 extern...

Specifications 11 - 7 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 ...

11 - 8 Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 Logic Interface SoundStructure Control System Pin Signal Pin Signal 1 - 1 - 2 TX 2 RX 3 RX 3 TX 4 - 4 - 5 Ground 5 Ground 6 - 6 - 7 CTS 7 RTS 8 RTS 8 CTS 9 - 9 - Remote Control 1 Pin Signal Pin Signal 1 +5 V 14 Logic Input 1 2...

Specifications 11 - 9 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 conn...

11 - 10 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. T S T T S S T S T S T S T T S S R T T R...

12 - 1 12 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 assoc...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 12 - 2 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 in...

A - 1 A Command Protocol Reference Guide Introduction This chapter describes the SoundStructure™ command protocol used to control and configure the SoundStructure products via the RS-232 and Ethernet interfaces. The target audience for this document is the control system programmer and other applica...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 2 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...

Command Protocol Reference Guide A - 3 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 4 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. The SoundStructure Ethernet interface can be...

Command Protocol Reference Guide A - 5 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....

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 6 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 ...

Command Protocol Reference Guide A - 7 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 crea...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 8 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 pa...

Command Protocol Reference Guide A - 9 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. int...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 10 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 followi...

Command Protocol Reference Guide A - 11 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 fo...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 12 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 indic...

Command Protocol Reference Guide A - 13 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 d...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 14 <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. ste...

Command Protocol Reference Guide A - 15 <num>One or more <num> arguments are required to define the global channel index (indices) of the physical channel(s) in the virtual channel. The <num> argument is an integer argument.As an example, consider two SoundStructure C16 devices lin...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 16 vcdef Acknowledgements When a virtual channel definition command with the vcdef action is successfully executed, SoundStructure will send an acknowledgement in the same format as the command. The acknowledgement will be sent t...

Command Protocol Reference Guide A - 17 <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 A - 18 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 er...

Command Protocol Reference Guide A - 19 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 ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 20 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> <ne...

Command Protocol Reference Guide A - 21 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 22 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 c...

Command Protocol Reference Guide A - 23 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 be...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 24 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 v...

Command Protocol Reference Guide A - 25 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. Write-only commands support the...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 26 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 maxi...

Command Protocol Reference Guide A - 27 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 ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 28 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...

Command Protocol Reference Guide A - 29 Description This parameter sets the fader level (in dB) in the digital domain. Interpretation of the Arguments The Channel Type entry indicates that this command accepts a virtual channel name as an argument.The Value Type entry indicates that this command acc...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 30 set fader "Amplifier" 10val fader "Amplifier" 10.0 set fader max "Amplifier" 10val fader max "Amplifier" 10.0 set fader min "Amplifier" -20val fader min "Amplifier" -20.0 get fad...

Command Protocol Reference Guide A - 31 Description This parameter sets the fader level (in dB) in the digital domain. Examples line_out_gain Line Output Gain System Limits Minimum: -100.0, Maximum: 20.0, Resolution: 0.1 Default 0.0 User Limits Supported Yes Argument Argument value Command Response ...

Command Protocol Reference Guide A - 33 mute Digital Mute 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. Examples set mic_in_gain "Table Mic 1" 48 val mic_in_gain "Ta...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 34 phantom 48 V Phantom Power Description Enables or disable phantom power on mic inputs. Setting phantom to 1 enables phantom power, while setting it to 0 disables phantom power. Examples safety_mute Safety Mute Description This...

Command Protocol Reference Guide A - 35 trim Gain Trim For Virtual Channels 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. For example, in...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 36 Matrix Parameters matrix_balance Matrix Crosspoint Balance Description The matrix_balance parameter is available at crosspoints where stereo virtual channels are mixed to mono or stereo virtual channels. The matrix_balance par...

Command Protocol Reference Guide A - 37 matrix_gain Matrix Crosspoint Gain Description This parameter sets the gain (in dB) for the specified crosspoint in the matrix mixer. Examples matrix_gate Enable Gated Signal At Crosspoint Argument Argument value Channel Type Matrix Value Type Floating-Point R...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 38 Description This parameter selects whether the gated (1) or ungated (0) version of the input signal is sent to the output. Examples matrix_gate_type Select Gating Type Row Phys Chans Conferencing Mic/Line Input, Sound Reinforc...

Command Protocol Reference Guide A - 39 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 matrix_invert Matrix Crosspoint Inversion Descrip...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 40 matrix_mute Matrix Crosspoint Mute Description Mutes or unmutes the specified crosspoint in the matrix mixer. Setting matrix_mute to 0 unmutes the crosspoint; setting matrix_mute to 1 mutes the crosspoint. Examples matrix_pan ...

Command Protocol Reference Guide A - 41 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. Examples Telephony Pa...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 42 Command Input channel Output channel phone_auto_answer_en ✔ phone_connect ✔ phone_dial ✔ phone_dial_tone_gain ✔ phone_dtmf_gain ✔ phone_entry_tone_en ✔ phone_exit_tone_en ✔ phone_flash ✔ phone_flash_delay ✔ phone_redial ✔ phon...

Command Protocol Reference Guide A - 43 phone_auto_answer_en Enable Auto-Answer For Telephony Interface Description This parameter enables (1) or disables (0) the auto-answer feature for the telephony interface. Examples phone_connect Connect Or Disconnect Telephony Interface Description This parame...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 44 phone_dial Dial The Telephony Interface Description This command dials the specified string of digits on the telephony interface. This parameter can be used to dial one digit at a time or many digits all at once. For the PSTN ...

Command Protocol Reference Guide A - 45 phone_dial_tone_gain Dial Tone Gain Description This parameter controls the gain that is applied to the incoming phone signal when dial tone is present. Examples phone_dtmf_gain Telephony Input DTMF Gain Argument Argument value Channel Type Virtual Channel Val...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 46 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 parame...

Command Protocol Reference Guide A - 47 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 p...

Command Protocol Reference Guide A - 49 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.Acknowledgemen...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 50 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. To adjust the level of the DTMF digits played back to...

Command Protocol Reference Guide A - 51 Values argentina : Argentinaaustralia : Australiaaustria : Austriabahrain : Bahrainbelgium : Belgiumbrazil : Brazilbulgaria : Bulgariacanada : Canadachile : Chilechina : Chinacolombia : Colombiacroatia : Croatiacyprus : Cyprusczech_republic : Czech Republicden...

Command Protocol Reference Guide A - 53 Description This parameter configures the PSTN interface for operation in a specific country. pstn_flash_delay_override Override Countr y Code Flash Delay Description This parameter controls whether or not the flash hook delay is determined by the default pstn...

Command Protocol Reference Guide A - 55 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 Description This parameter sets the gain (in dB) of the signal going to the PSTN ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 56 eq_en Enable All Equalizer Processing Description This parameter enables (1) or disables (0) all equalizer processing (peq, geq, etc.) for the specified virtual channel. Examples eq_type Select Graphic or Parametric Equalizer ...

Command Protocol Reference Guide A - 57 geq_compensate Enable Gain Compensation For Graphic Equalizer Description This parameter enables (1) or disables (0) gain compensation for the graphic equalizer. geq_en Enable Graphic Equalizer Description This parameter enables (1) or disables (0) the graphic...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 58 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 equalizat...

Command Protocol Reference Guide A - 59 Description This parameter enables (1) or disables (0) the high shelving filter for the specified virtual channel. high_shelf_frequency Frequency Of High Shelving Filter Description This parameter sets the cutoff frequency (in Hz) of the high shelving filter. ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 60 high_shelf_gain Gain Of High Shelving Filter Description This parameter sets the gain (in dB) of the high shelving filter at DC. high_shelf_slope Slope Of High Shelving Filter Description This parameter sets the slope of the h...

Command Protocol Reference Guide A - 61 horn_en Enable Horn Equalizer Description This parameter enables (1) or disables (0) the constant directivity horn equalizer for the specified virtual channel. horn_frequency Frequency of Horn Equalizer Description This parameter sets the cutoff frequency (in ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 62 hpf_en Enable High-Pass Filter Description This parameter enables (1) or disables (0) the high-pass filter for the specified virtual channel. hpf_frequency Frequency Of High-Pass Filter Description This parameter sets the freq...

Command Protocol Reference Guide A - 63 hpf_order Order of High-Pass Filter Description This parameter sets the order of the high-pass filter. Linkwitz-Riley filters only support even orders. If an odd order is specified for a Linkwitz-Riley filter, it will be internally rounded up to an even number...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 64 low_shelf_en Enable Low Shelving Filter Description This parameter enables (1) or disables (0) the low shelving filter for the specified virtual channel. low_shelf_frequency Frequency Of Low Shelving Filter Description This pa...

Command Protocol Reference Guide A - 65 low_shelf_gain Gain Of Low Shelving Filter Description This parameter sets the gain (in dB) of the low shelving filter at DC. low_shelf_slope Slope Of Low Shelving Filter Description This parameter sets the slope of the low shelving filter. Argument Argument v...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 68 peq_band_en Enable Parametric Equalizer Band Description This parameter enables (1) or disables (0) the specified band of the parametric equalizer for the specified virtual channel. For conference link physical channels, the b...

Command Protocol Reference Guide A - 69 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...

Command Protocol Reference Guide A - 71 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 p...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 72 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. dp_gate_decay Gate Decay Time Description ...

Command Protocol Reference Guide A - 73 dp_gate_en Enable Gate Description This parameter enables (1) or disables (0) the gate function of the dynamics processor. This parameter and dp_en must be enabled for the gate to function. dp_gate_hold Gate Hold Time Description This parameter sets the amount...

Command Protocol Reference Guide A - 75 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 ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 76 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. dp_exp_en Enable Expander Description This pa...

Command Protocol Reference Guide A - 77 Description This parameter sets the ratio of the target gain applied by the expander versus the difference between the input signal level and the expander threshold. For example, if the expander ratio is 2 (i.e., 2:1) and the input signal level is 3 dB below t...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 78 dp_comp_attack Compressor Attack time 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 t...

Command Protocol Reference Guide A - 79 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 Description This parameter enable...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 80 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 th...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 84 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. dp_peak_thresh Peak Limiter threshold Descr...

Command Protocol Reference Guide A - 85 Description This parameter enables (1) or disables (0) the acoustic echo cancellation (AEC) algorithm. aec_noise_fill Enable Noise Fill Description This parameter enables (1) or disables (0) the noise fill algorithm in the AEC. aec_ref AEC Reference Descriptio...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 86 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...

Command Protocol Reference Guide A - 89 fb_filter_bandwidth Feedback Reduction filter Bandwidth Description This parameter sets the bandwidth (in octaves) for all the filters of the feedback reduction algorithm. fb_filter_decay_en Enable Filter Decay Mode In Feedback Reduction Algorithm Description ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 90 fb_filter_reset Reset One Of The Feedback Reduction Filters Description Setting this parameter resets the specified filter in the feedback reduction algorithm. Redpoint will likely set this parameter for filters it has convert...

Command Protocol Reference Guide A - 91 fb_safe_mode_atten Safe Mode Attenuation For Feedback Reduction Description This parameter defines the maximum amount of attenuation (in dB) applied to the input if all the filters are used up and the feedback reduction algorithm continues to detect singing. S...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 92 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 ...

Command Protocol Reference Guide A - 93 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 ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 94 nc_level Noise Cancellation Level Description This parameter sets the amount of cancellation (in dB) applied by the noise cancellation algorithm. sig_gen_gain Signal Generator Gain Description This parameter sets the gain of t...

Command Protocol Reference Guide A - 97 sig_gen_tone_freq Signal Generator Tone Frequency 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. sig_gen_type Signal Generator Type Description This parameter sets t...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 98 Input Path Parameters cr_ungated_type Select Processing For Ungated Signal Description This parameter selects the version of signal to use for the ungated triune signal of the specified virtual channel. sr_delay_type Select De...

Command Protocol Reference Guide A - 99 sr_ungated_type Select Processing For Ungated Signal Description This parameter selects the version of signal to use for the ungated triune signal of the specified virtual channel. ungated_delay_comp_en Enable Delay Compensation For Triune Signals Description ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 100 Automixer Parameters am_adapt_thresh Automixer Adaptive Threshold 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 con...

Command Protocol Reference Guide A - 101 am_chairman Automixer Chairman Microphone Description When this parameter is set to 1, the microphone is considered a chairman microphone. am_chan_bias Automixer Channel Bias Description This parameter sets the channel bias (in dB) for the associated micropho...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 102 am_decay_time Automixer Decay Time 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 ...

Command Protocol Reference Guide A - 103 am_gain_sharing Enable Gain-Sharing Automixer Mode 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 am_group Automixer Group De...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 104 Examples am_hold_time Automixer Hold Time Description This parameter defines how long (in ms) the microphone in the specified automixer group will be considered active after the last detected significant level on the micropho...

Command Protocol Reference Guide A - 105 am_nom_limit NOM Limit Description This parameter sets the NOM limit for the microphone with respect to its automixer group. am_off_atten Automixer Off Attenuation Description This parameter defines how much attenuation (in dB) is applied to a gated microphon...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 106 am_priority Automixer Microphone Priority 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). a...

Command Protocol Reference Guide A - 107 am_slope Gain Sharing Automixer Slope 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. For example, if a microphone has a level that...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 108 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 analo...

Command Protocol Reference Guide A - 109 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. digital_gpio_state Digital GPIO Pin Status Description This para...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 110 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. Control Port Parameters eth_settings Ethernet Settings Description This p...

Command Protocol Reference Guide A - 111 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 Exampleset eth_settings 1 "mode='static',addr='172.22.2.200',dns='172.22.1.1',gw...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 112 Description This parameter selects the method for obtaining the IP address of the ethernet port. eth_mac Get Ethernet MAC Address Description This parameter gets the MAC address for the system's Ethernet port. The value will ...

Command Protocol Reference Guide A - 113 ir_key_held Key Held On IR Remote 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 t...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 114 ser_flow RS-232 Flow Control 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. Examples System Parameters dev_boo...

Command Protocol Reference Guide A - 115 dev_firmware_ver Firmware Version Description This parameter returns the device’s firmware version. Examples dev_ntp_ser ver NTP Ser ver Description This parameter gets or sets the name of the network time protocol (NTP) server used to set the system time. de...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 116 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. A value of warning indicates...

Command Protocol Reference Guide A - 117 dev_type Device Type Description This parameter returns the type of the device. dev_uptime System Uptime Description This parameter returns the amount of time since the last reboot. The value returned is formatted as days:hours:minutes:seconds. For example, a...

Command Protocol Reference Guide A - 119 Description This parameter returns the voltage (in Volts) of the +15 V power supply. sys_factor y_reset Restore System To Factor y Settings Description Setting this parameter restores the device to its factory settings, erasing all user data but retaining the...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 A - 120 sys_reboot Reset The Device Description Setting this parameter causes all linked devices to reboot as if a power-cycle has occurred. Argument Argument value Channel Type Global System Value Type Void Read/Write Mode Write-Onl...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 B - 2 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 t...

Designing Audio Conferencing Systems B - 3 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 processe...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 B - 4 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 als...

Designing Audio Conferencing Systems B - 5 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 microp...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 B - 6 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 i...

Designing Audio Conferencing Systems B - 7 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 B - 8 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 w...

Designing Audio Conferencing Systems B - 9 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...

Designing Audio Conferencing Systems B - 11 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 B - 12 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 con...

Designing Audio Conferencing Systems B - 13 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 vi...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 B - 14 200 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. Transmission Delay In...

Designing Audio Conferencing Systems B - 15 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. While the delay in the network will increase the perception of echoes, i...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 B - 16 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 dB.The non-linear suppression employed by acoustic echo cancellers is us...

Designing Audio Conferencing Systems B - 17 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. Similarly with respect to the acoustic echo c...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 B - 18 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,...

Designing Audio Conferencing Systems B - 19 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 amp...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 B - 20 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 the audio from the remote telephone talkers' speech, the line e...

Designing Audio Conferencing Systems B - 21 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...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 B - 22 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 loudspeake...

Designing Audio Conferencing Systems B - 23 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 ...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 B - 24 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. The next figure shows the room...

Designing Audio Conferencing Systems B - 25 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 po...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 B - 26 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 o...

Design Guide for the Polycom SoundStructure C16, C12, C8, and SR12 B - 28 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. There a...