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Table Of Contents
Chapter 13 Vocoder—Basics 171
Gating Background Noises in the Side Chain
If the Side Chain signal is compressed, as recommended, the level of breath, rumble,
and background noises will rise. These background noises can cause the Vocoder bands
to open, but this is normally not intended. In order to eliminate these noises, its
therefore a good idea to employ a noise gate before compression and treble boosting.
If the Side Chain signal is gated appropriately, you may find that you want to reduce
the analysis Release value. When gating speech and vocals, the Hysteresis parameter is
important. Threshold defines the level, above which the gate will open. Hysteresis
defines a lower Threshold level, under which the gate will close. The value is relative to
the Threshold level. The graphic shows a Threshold setting, which is well-adapted to
compressed speech. Unwanted triggering by low or high frequency noise is avoided by
the Noise Gates’ dedicated sidechain filters. The Hold, Release, and Hysteresis values
shown are typical level envelopes, suitable for most vocal and speech signals.