FXAlg #954: Compress/Expand ¥ FXAlg #955: Comp/Exp + EQ
Algorithm Reference-149
threshold. The expander release time may be set quite long. An expander may be used to suppress background
noise in the absence of signal, thus typical expander settings use a fast attack (to avoid losing real signal), slow
release (to gradually fade out the noise), and the threshold set just above the noise level. You can set just how far to
drop the noise with the expansion ratio.
Expansion Transfer Characteristic
The signal being compressed/expanded may be delayed relative to the side chain processing. The delay allows the
signal to start being compressed (or stop being expanded) just before an attack transient arrives. Since the side chain
processing ÒknowsÓ what the input signal is going to be before the main signal path does, it can tame down an
attack transient by compressing the attack before it actually happens (or releasing the expander before the attack
happens). This feature works whether the side chain is configured for feed-forward or feedback.
A meter is provided to display the amount of gain reduction that is applied to the signal as a result of compression
and expansion.
The algorithm Comp/Exp + EQ differs from Compress/Expand in that the compressor and expander sections are
followed by equalization filters. The output signal may be filtered with bass and treble shelving filters and a mid-
range parametric filter.
Parameters:
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In/Out
In or Out
Out Gain
Off, -79.0 to 24.0 dB
FdbkComprs
In or Out
Comp Atk
0.0 to 228.0 ms
Exp Atk
0.0 to 228.0 ms
Comp Rel
0 to 3000 ms
Exp Rel
0 to 3000 ms
SmoothTime
0.0 to 228.0 ms
Signal Dly
0.0 to 25.0 ms
Comp1Ratio
1.0:1 to 100.0:1, Inf:1
Exp Ratio
1:1.0 to 1:17.0
Comp1Thres
-79.0 to 0.0 dB
Exp Thres
-79.0 to 0.0 dB
Comp2Ratio
1.0:1 to 100.0:1, Inf:1
MakeUpGain
Off, -79.0 to 24.0 dB
Comp2Thres
-79.0 to 0.0 dB
Reduction
-dB 40 20 12 8 6 4 2 0
Out
Amp
In Amp
Threshold
