The  AVC monitors the ambient noise level for a single zone. See also 'Automatic Volume Control' (AVC) settings (22).

The digital audio matrix that takes this measurement is referred to as a noise monitor.

For this feature, the following components are required:

  • 'Automated volume control microphone' PCA2007
  • 'Automated volume control module' PCA2008
  • Speaker line in close proximity to the microphone

These components must be connected to the same digital audio matrix:

  • 'Digital audio matrix (4/4/4)' PC2001, or
  • 'Digital audio matrix (4/4/16)' PC2003, or
  • 'Digital audio matrix no supervision (4/4/0)' PC2005, or
  • Cerberus PACE Compact digital audio matrix board PC1001 and PC1002

In case the ambient noise level exceeds a configurable threshold, a new AVC attenuation value is calculated and shared in the whole network. Other network participants can utilize this value to control their output volume.

For this feature to work perfectly, the following points must be observed:

  • Up to four AVC-MIC microphones can be used for a single zone.
  • The speakers and AVC-microphones must be arranged close to each other.
  • The AVC-microphones must all be located in a single zone, if possible, in the same room, without interference sound from other zones.
  • The AVC-microphones must be connected via an AVC monitoring module.
  • The AVC-monitoring module needs to be connected to the fourth analog audio input of the digital audio matrix (IN4).
  • The analog audio output which has the speaker line connected is free to choose.
  • Only a digital audio matrix with analog audio inputs is able to monitor the noise level:
    • 'Digital audio matrix (4/4/4)' PC2001
    • 'Digital audio matrix (4/4/16)' PC2003
    • 'Digital audio matrix no supervision (4/4/0)' PC2005
    • Cerberus PACE Compact PC1001, PC1002
  • The AVC-microphone input and analog audio output of the measurement zone need to be connected to the same station.
  • All analog audio outputs of all the digital audio matrices can be controlled by the AVC values.
  • A logic control input is used to process errors detected by the AVC monitoring module.
Calculation of the AVC attenuation value
Other network participants utilizing the AVC attenuation value

To configure the AVC system, follow the steps described. First you need to configure the noise monitor.

  1. Open the audio input configuration page
  1. Configure the fourth analog audio input ('IN4'). Name it 'AVC-MIC my zone name'
  1. Set the type to Mic and adjust the gain, so the measured value is below -40 dB if the environment is silent
  1. Disable the compressor limiter functionality
  1. Set to feed the network with a signal and choose a channel number
  1. Switch the tab at the bottom of the configuration page to AVC settings
  1. Switch on the AVC feature by clicking on the Enable switch
  1. Choose the analog audio output number 1…4 of the amplifier which is supplying the speaker line in the measurement zone
  1. Set the threshold for the measured analog audio input signal. If this threshold is exceeded, the AVC attenuation value is increased. The default value is -20 dB
  1. Set the maximum attenuation value to default -12 dB
  1. Set the response and fade rate to 6 dB/s. Values above this will increase the control speed, but they may also cause the system to become unstable.
  1. Set the averaging time to 100 ms and the Feedback Factor to 50%
  1. Make sure to disable the 'Show RMS' and 'IO Triggered' switches
  1. Open the audio output configuration
  1. Enable the 'Use AVC of' checkbox and enter the own station ID at the output which is supplying the speaker line in the measurement zone

To see the actual AVC attenuation value

  1. Open the system overview
  1. Select the station which acts as the noise monitor
  1. Open the 'Dynamic Station Information' page by pressing <F8>.
  • The actual value is displayed in the AVC gauge

Control output zones via the measured AVC value

  1. Open the audio output configuration
  1. Enable the 'Use AVC of' checkbox
  1. Choose the Station ID of the noise monitor
  • This output will now be controlled by the AVC value