E-MU 1212M PCIe - Manual (Page 95)

5 - Effects
Core Effects Descriptions
E-MU PCIe Digital Audio Systems 95
Gate
This parameter enables automatic gain reduction on signals that fall from 1 to 120dB
below the Threshold point (or Soft Knee threshold, if enabled.) This can act effectively
as a “noise gate” on low-level signals that have been boosted by the action of the Gain
or Soft Knee parameters. The gating action follows a somewhat soft-kneed contour of
its own so that turn-on and turn-off at the gate threshold is not too abrupt.
0dB
-10dB
-20dB
-30dB
-40dB
-50dB
-60dB
-70dB
-80dB
Threshold: -20dB
Ratio = 4:1
Gain = +15dB
Gate
Gate
Threshold
-30dB
In this example, the Gain has been boosted by +15dB. The Gate cancels out the +15dB Gain
boost below the Gate Threshold. Signal levels above the Gate Threshold will be boosted; signal
levels below this point will not be boosted and will be 15dB lower in volume.
Note that, strictly speaking, the term “gate” is a misnomer in this context, since the
action of this parameter is simply to cancel out gain increases that resulted from the
settings of other parameters. This can be seen by the arrows in the diagram as the gain
is reduced below the Gate threshold back down to the dotted line representing unity
gain. The result is that if the Gain parameter is set negative or the Soft Knee parameter
is disabled, the Gate parameter will have no effect.
Lookahead Delay
Sharp waveform peak is missed by compressor.
Add Lookahead (neg values) to compress peak.
Add Delay (pos values) to allow peak through.
Comp Lookahead/Delay
This parameter controls compressor
lookahead or delay by setting the
relative time offset, in milliseconds,
between the compressor's signal path
and its sidechain path.
At negative values, this parameter lets
the level detector in the compressor's
sidechain “look into the future” up to
100 milliseconds in order to antic-
ipate upcoming peaks in the signal -
accomplished of course, by inserting
delay into the signal path. This
lookahead technique allows the use
of slower attack times without
missing signal peaks.
At positive values, the signal path delay is zero; instead, a delay of up to 50 milli-
seconds is inserted into the sidechain path containing the level detector. This delay can
be used intentionally to cause the compressor to miss signal peaks, retaining the