Bosch Appliances 3.5 manual 1: AVC settings, Proceed as follows to configure AVC

Praesideo 3.5 Installation and User Instructions 9 System Configuration

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•Make sure that all loudspeakers are connected to the system, set at the correct power level, are aimed (if necessary) and are working.

•Adjust the nominal output level of all audio outputs in the zone to the level required to have the correct speech intelligibility at maximum ambient noise level.

•Make sure that the the audio delay setting of the applicable power amplifier outputs is set to a value < 2 s. After the calibration the audio delay can be set back to the correct value. Very long delay settings, e.g. for tunnel applications, may cause wrong calibration results.

Proceed as follows to configure AVC:

1Go to the AVC settings category of the Zone Configuration page. A screen similar to the one in figure 49.1 appears in the main frame of the web interface.

figure 49.1: AVC settings

2Put a check mark in the Enabled checkbox to enable AVC for calls. The ambient noise level that is used to adjust the volume of the call, is measured just before the start of the call.

Note

The AVC settings only apply to the audio outputs of power amplifiers. It is not possible to apply AVC to the audio outputs of basic amplifiers or other units.

3Normally the AVC works for calls. When the AVC should also work for BGM, put a checkmark in the BGM box. The ambient noise level that is used to

adjust the volume of the BGM, is measured continuously.

4By default AVC also works for the emergency calls, but if Control Emergency is disabled then emergency calls will be broadcast at maximum (configured) level.

Note

When AVC is enabled for BGM, make sure that the sensing microphone is not near the loudspeakers. If the sensing microphone is near the loudspeakers, the BGM itself is seen as ambient noise and the volume level of the BGM will increase to the maximum volume level (feedback).

5Choose the audio input to which the sensing microphone is connected from the Sense input dropdown list.

6Select the call margin from the Call margin dropdown list. This is the threshold level of the AVC function. When the ambient noise level is below the call level by more than the call margin, the AVC starts attenuating the call.

Note

A value of 12 dB is a practical value. A higher value results in a bigger difference between the volume levels of the calls and the ambient noise. However, this requires more (or bigger) loudspeakers and power amplifiers to reach the high call volume when the volume level of the ambient noise is high.

7Select the release time from the Release time dropdown list. This is the time between the end of the call and the start of the ambient noise measurement.

Note

A value of 6 s is a practical value. A short release time combined with a long reverberation time can cause a high call volume level.

Bosch Security Systems 2011-02