Apple Logic Express 7 - Manual (Page 32)

32 Chapter 4 Dynamic
When you’re working with noise gates, you’ll run across scenarios where the useful
signal and the noise signal have levels that are near enough to be perceived as
identical. A typical example is the crosstalk of a hi-hat—its signal tends to bleed into
the snare drum track when you’re recording a drum kit. If you’re using a noise gate to
isolate the snare, you’ll find that the hi-hat will also open the gate in many cases. To
avoid this effect, the Noise Gate offers Side Chain filters.
When you press and hold the Monitor button, you can audition the Side Chain signal.
You can then set the filters to only allow frequencies that contain a particularly loud,
useful signal to pass. For this example, we’ll use the Noise Gate’s High Cut filter—that
only allows the bottom end and mids of the snare to pass, and cuts the higher
frequencies of the hi-hat. When you switch Side Chain Monitoring off, it will be much
easier to set a suitable Threshold level. This will be a value that is only exceeded by the
level of the louder useful signal—the frequencies that make up the snare’s
fundamental tone, in our example. Put simply, the Noise Gate only allows the sound of
the snare to pass. Should the need arise, you can follow much the same procedure to
isolate a kick or snare drum within an entire mixdown.
Silver Gate
The Silver Gate is a cut-down version of the Noise Gate. It is limited to Threshold,
Lookahead, Attack, Hold, and Release controls.