63 lines
2.1 KiB
Text
63 lines
2.1 KiB
Text
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#lang scribble/manual
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@(require (for-label racket))
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@title{CompanderD}
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Compressor, expander, limiter, gate, ducker.@section{related}
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Classes/Amplitude, Classes/Compander, Classes/Normalizer, Classes/Limiter
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@section{categories}
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UGens>Dynamics
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@section{description}
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CompanderD passes the signal directly to the control input, but
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adds a delay to the process input so that the lag in the gain clamping
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will not lag the attacks in the input sound.
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@section{classmethods}
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@section{method}
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ar
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@section{argument}
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in
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The signal to be compressed / expanded / gated.
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@section{argument}
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thresh
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Control signal amplitude threshold, which determines the break point between slopeBelow and slopeAbove. Usually 0..1. The control signal amplitude is calculated using RMS.
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@section{argument}
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slopeBelow
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Slope of the amplitude curve below the threshold. If this slope > 1.0, the amplitude will drop 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.
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@section{argument}
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slopeAbove
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Same thing, but above the threshold. Values < 1.0 achieve compression (louder signals are attenuated); > 1.0, you get expansion (louder signals are made even louder). For 3:1 compression, you would use a value of 1/3 here.
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@section{argument}
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clampTime
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The amount of time it takes for the amplitude adjustment to kick in fully. This is usually pretty small, not much more than 10 milliseconds (the default value). I often set it as low as 2 milliseconds (0.002).
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@section{argument}
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relaxTime
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The amount of time for the amplitude adjustment to be released. Usually a bit longer than clampTime; if both times are too short, you can get some (possibly unwanted) artifacts.
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@section{argument}
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mul
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Output will be multiplied by this value.
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@section{argument}
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add
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This value will be added to the output.
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@section{Discussion}
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If any of this is confusing, see http://en.wikipedia.org/wiki/Audio_level_compression
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