Specifications

Chapter 27: Plug-In and Hardware Inserts 445
Using a Key Input for Side-Chain
Processing
Some plug-ins (such as the DigiRack Compres-
sor, Limiter, Gate, and Expander/Gate) feature
side-chain processing capabilities. Side-chain
processing allows you to trigger a plug-in from a
separate reference track or external audio
source. The source used for triggering is referred
to as the Key Input. Key inputs are monophonic.
A typical use for this feature is to control the dy-
namics of one audio signal using the dynamics
of another signal (the Key Input). For example, a
kick drum track could be used to trigger gating
of a bass track to tighten it up, or a rhythm gui-
tar track could be used to gate a keyboard pad.
Another side-chain usage, is to create a tunable
signal generator: Use a Signal Generator plug-in
on an Auxiliary Input, add a gate plug-in to the
track, then feed its gate with a side-chain from
the kick. The generator is tunable (based on
what tone you record).
Key Input Filters
Some plug-ins feature key high pass and low
pass filters. These controls allow you to define a
specific frequency range in the Key Input signal
with which to trigger the plug-in effect. A com-
mon production technique is to use these con-
trols to filter a drum track so that only specific
high frequencies (a hi-hat, for example) or low
frequencies (a tom or a kick, for example) trigger
the effect.
To use a Key Input for side-chain processing:
1 From the Key Input menu, choose the input
or bus carrying the audio you want to use to trig-
ger the plug-in.
2 Click External Key to activate side-chain pro-
cessing.
3 To hear the audio source you have selected to
control side-chain input, click Key Listen.
4 To filter the Key Input so that only specific fre-
quencies trigger the plug-in, use the Key HPF
and Key LPF controls (if available) to select the
frequency range.
5 Begin playback. The plug-in uses the input or
bus that you chose as a Key Input to trigger its
effect.
6 Adjust the plug-in’s Threshold control (if
available) to fine-tune Key Input triggering. Also
experiment with the Send level, by feeding the
side-chain more or less gain.
7 Adjust other controls to achieve the desired ef-
fect.
RTAS plug-ins do not provide side-chain
processing when used on TDM-based sys-
tems; use the TDM versions of plug-ins on
TDM-based systems if you want to use side-
chain processing.
Choosing a Key Input