Compander | SuperCollider 3.12.2 Help

Description

General purpose (hard-knee) dynamics processor.

Class Methods

Compander.ar(in: 0.0, control: 0.0, thresh: 0.5, slopeBelow: 1.0, slopeAbove: 1.0, clampTime: 0.01, relaxTime: 0.1, mul: 1.0, add: 0.0)

Arguments:

in	The signal to be compressed / expanded / gated.
control	The signal whose amplitude determines the gain applied to the input signal. Often the same as in (for standard gating or compression) but should be different for ducking.
thresh	Usually between 0 and 1. Amplitude threshold of the control signal, which determines the break point between slopeBelow and slopeAbove. The control signal amplitude is calculated using RMS.
slopeBelow	Slope of applied amplitude curve if control signal amplitude is below `thresh`. If > 1.0, the amplitude drops off more quickly the softer the control signal gets; when the control signal is close to 0 amplitude, the output should be exactly zero -- hence, noise gating. Values < 1.0 are possible, but it means that a very low-level control signal will cause the input signal to be amplified, which would raise the noise floor.
slopeAbove	Slope of applied amplitude curve if control signal amplitude is above `thresh`. Values < 1.0 achieve compression (louder signals are attenuated) whereas values > 1.0 expand (louder signals are made even louder). A value of `1/3` achieves a 3:1 compression.
clampTime	time (in seconds) it takes for the amplitude adjustment to kick in fully after the control signal is above `thresh`. Usually a small value around 10ms (0.01), often set as low as 2ms (0.002).
relaxTime	time (in seconds) for the amplitude adjustment to be released (control signal below `thresh`). Usually longer than `clampTime`; depending on the input and control signal, setting both times too short results in (possibly unwanted) artifacts.
mul	output is multiplied by this value.
add	value added to the output.

Discussion:

See for example http://en.wikipedia.org/wiki/Audio_level_compression for a more in-depth explanation.

Examples

Clean signal (for reference)( { Decay2.ar( Impulse.ar(8, 0, LFSaw.kr(0.3, 1, -0.3, 0.3)), 0.001, 0.3 ) * Mix.ar(Pulse.ar([80, 81], 0.3)) }.play; )

Noise gate( { var z; // signal (clean) z = Decay2.ar( Impulse.ar(8, 0, LFSaw.kr(0.3, 1, -0.3, 0.3)), 0.001, 0.3 ) * Mix.ar(Pulse.ar([80, 81], 0.3)); // apply gate (mouse x sets treshold) Compander.ar(z, z, thresh: MouseX.kr(0.001, 1), slopeBelow: 10, slopeAbove: 1, clampTime: 0.01, relaxTime: 0.01 ) }.play; )

Compressor( { var z; // signal (clean) z = Decay2.ar( Impulse.ar(8, 0, LFSaw.kr(0.3, 1, -0.3, 0.3)), 0.001, 0.3 ) * Mix.ar(Pulse.ar([80, 81], 0.3)); // apply compression (mouse x sets amount) Compander.ar(z, z, thresh: MouseX.kr(0.01, 1), slopeBelow: 1, slopeAbove: 0.5, clampTime: 0.01, relaxTime: 0.01 ) }.play; )

Limiter( { var z; // signal (clean) z = Decay2.ar( Impulse.ar(8, 0, LFSaw.kr(0.3, 1, -0.3, 0.3)), 0.001, 0.3 ) * Mix.ar(Pulse.ar([80, 81], 0.3)); // apply limiter (mouse x sets amount) Compander.ar(z, z, thresh: MouseX.kr(0.01, 1), slopeBelow: 1, slopeAbove: 0.1, clampTime: 0.01, relaxTime: 0.01 ) }.play; )

Sustainer( // note the pops at the beginning of signal due to lack of lookahead { var z; // signal (clean) z = Decay2.ar( Impulse.ar(8, 0, LFSaw.kr(0.3, 1, -0.3, 0.3)), 0.001, 0.3 ) * Mix.ar(Pulse.ar([80, 81], 0.3)); // apply sustainer Compander.ar(z, z, thresh: MouseX.kr(0.1, 1), slopeBelow: 0.1, slopeAbove: 1, clampTime: 0.01, relaxTime: 0.01 ) * 0.1 }.play; )

helpfile source: /usr/local/share/SuperCollider/HelpSource/Classes/Compander.schelp
link::Classes/Compander::

Compander : UGen : AbstractFunction : Object

Description

Class Methods

Compander.ar(in: 0.0, control: 0.0, thresh: 0.5, slopeBelow: 1.0, slopeAbove: 1.0, clampTime: 0.01, relaxTime: 0.1, mul: 1.0, add: 0.0)

Arguments:

Discussion:

Inherited class methods

Instance Methods

Inherited instance methods

Examples