Dynamic Range Compression (DRC)

Dynamic Range Compression (DRC) is a feature in the Zenitel IP devices. The DRC is an audio signal processing function that helps even out the loud and quiet parts. Lower signals will get gain applied, but not more than there is headroom for up to digital full scale.

For intercom devices and IP Speakers the DRC will normally have a good effect on regular speech signals, and will often increase the loudspeaker output noticeably. For already maximized signals, such as prerecorded alarm tones, DRC will have little or no effect.

The DRC function is by default disabled. The DRC is a dynamic digital signal gain adjustment function, and some signal clipping may occur if the DRC value is set too high. Normally a value of 10dB or less gives a good effect. Even when set to 0dB one will experience increased volume if the input signal is low. The DRC function works very well in combination with the Automatic Volume Control (AVC).

Configuring the DRC feature

Configuration is done from the Audio Settings menu. First enable Advanced Configuration mode. Depending on the mode of operations, select:

• Edge mode: Edge Configuration > Audio Settings > Audio signal processing
• SIP mode: SIP Configuration > Audio Settings > Audio signal processing
• ICX-AlphaCom mode: Advanced ICX-AlphaCom > Audio Settings > Audio signal processing

Dynamic Range Compression configuration menu (firmware 7 and later)

• Enable DRC: Check the box to enable the DRC function.
• DRC gain: Specifies the maximum gain which will be added to the signal. Note that some signal clipping may occur if the DRC is configured to use high gain.