90 lines
2.2 KiB
Text
90 lines
2.2 KiB
Text
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#lang scribble/manual
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@(require (for-label racket))
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@title{CombL}
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Comb delay line with linear interpolation.@section{related}
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Classes/CombC, Classes/CombN, Classes/BufCombL
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@section{categories}
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UGens>Delays
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@section{description}
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Comb delay line with linear interpolation. See also link::Classes/CombN::
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which uses no interpolation, and link::Classes/CombC:: which uses cubic
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interpolation. Cubic interpolation is more computationally expensive
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than linear, but more accurate.
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The feedback coefficient is given by the equation
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@racketblock[ fb == 0.001 ** (delay / decay.abs) * decay.sign :: where 0.001 is -60 dBFS.
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]
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@section{classmethods}
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@section{method}
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ar, kr
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@section{argument}
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in
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The input signal.
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@section{argument}
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maxdelaytime
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The maximum delay time in seconds. Used to initialize the delay buffer size.
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@section{argument}
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delaytime
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Delay time in seconds.
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@section{argument}
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decaytime
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Time for the echoes to decay by 60 decibels. If this time is negative then the feedback coefficient will be negative, thus emphasizing only odd harmonics at an octave lower.
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Infinite decay times are permitted. A decay time of
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@racketblock[inf:: leads to a feedback coefficient of 1, and a decay time of ]
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@racketblock[-inf:: leads to a feedback coefficient of -1.
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]
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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{Examples}
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@racketblock[
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// These examples compare the variants, so that you can hear the difference in interpolation
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// Comb used as a resonator. The resonant fundamental is equal to
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// reciprocal of the delay time.
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{ CombN.ar(WhiteNoise.ar(0.01), 0.01, XLine.kr(0.0001, 0.01, 20), 0.2) }.play;
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{ CombL.ar(WhiteNoise.ar(0.01), 0.01, XLine.kr(0.0001, 0.01, 20), 0.2) }.play;
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{ CombC.ar(WhiteNoise.ar(0.01), 0.01, XLine.kr(0.0001, 0.01, 20), 0.2) }.play;
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// with negative feedback:
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{ CombN.ar(WhiteNoise.ar(0.01), 0.01, XLine.kr(0.0001, 0.01, 20), -0.2) }.play;
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{ CombL.ar(WhiteNoise.ar(0.01), 0.01, XLine.kr(0.0001, 0.01, 20), -0.2) }.play;
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{ CombC.ar(WhiteNoise.ar(0.01), 0.01, XLine.kr(0.0001, 0.01, 20), -0.2) }.play;
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// used as an echo.
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{ CombL.ar(Decay.ar(Dust.ar(1,0.5), 0.2, WhiteNoise.ar), 0.2, 0.2, 3) }.play;
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::
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]
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