User Manual

CHAPTER 21. LIVE AUDIO EFFECT REFERENCE 287
are the same signal. But by using sidechaining, it is possible to compress a signal based
on the level of another signal or a specic frequency component. To access the Sidechain
parameters, unfold the Compressor window by toggling the button in its title bar.
The sidechain parameters are divided into two sections. On the left are the external controls.
Enabling this section with the Sidechain button allows you to select any of Live's internal
routing points from the choosers below. This causes the selected source to act as the
compressor's trigger, instead of the signal that is actually being compressed.
The Gain knob adjusts the level of the external sidechain's input, while the Dry/Wet knob
allows you to use a combination of sidechain and original signal as the compressor's trigger.
With Dry/Wet at 100%, the compressor is triggered entirely by the sidechain source. At
0%, the sidechain is effectively bypassed. Note that increasing the gain does not increase
the volume of the source signal in the mix. The sidechain audio is only a trigger for the
compressor and is never actually heard.
Note that FB mode and automatic Makeup are not available when using external sidechain.
On the right of the external section are the controls for the sidechain EQ. Enabling this
section causes the compressor to be triggered by a specic band of frequencies, instead of
a complete signal. These can either be frequencies in the compressed signal or, by using
the EQ in conjunction with an external sidechain, frequencies in another track's audio.
The headphones button between the external and EQ sections allows you to listen to only
the sidechain input, bypassing the compressor's output. Since the sidechain audio isn't
fed to the output, and is only a trigger for the compressor, this temporary listening option
can make it much easier to set sidechain parameters and hear what's actually making the
compressor work.
21.5.2 Compression Tips
This section presents some tips for using Compressor effectively, particularly with the
sidechain options.