83 lines
2.1 KiB
Text
83 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{BufCombL}
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Buffer based comb delay line with linear interpolation.@section{related}
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Classes/BufCombC, Classes/BufCombN, Classes/CombL
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@section{categories}
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UGens>Delays>Buffer
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@section{description}
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Comb delay line with linear interpolation which uses a buffer for its
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internal memory. See also link::Classes/BufCombN:: which uses no
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interpolation, and link::Classes/BufCombC:: 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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@section{classmethods}
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@section{method}
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ar
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@section{argument}
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buf
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Buffer number.
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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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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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@section{discussion}
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@section{Warning}
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For reasons of efficiency, the effective buffer size is limited to the previous power of two. So, if 44100 samples are allocated, the maximum delay would be 32768 samples.
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::
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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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// allocate buffer
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b = Buffer.alloc(s,44100,1);
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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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{ BufCombN.ar(b.bufnum, WhiteNoise.ar(0.01), XLine.kr(0.0001, 0.01, 20), 0.2) }.play;
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{ BufCombL.ar(b.bufnum, WhiteNoise.ar(0.01), XLine.kr(0.0001, 0.01, 20), 0.2) }.play;
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{ BufCombC.ar(b.bufnum, WhiteNoise.ar(0.01), XLine.kr(0.0001, 0.01, 20), 0.2) }.play;
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// with negative feedback:
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{ BufCombN.ar(b.bufnum, WhiteNoise.ar(0.01), XLine.kr(0.0001, 0.01, 20), -0.2) }.play;
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{ BufCombL.ar(b.bufnum, WhiteNoise.ar(0.01), XLine.kr(0.0001, 0.01, 20), -0.2) }.play;
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{ BufCombC.ar(b.bufnum, WhiteNoise.ar(0.01), XLine.kr(0.0001, 0.01, 20), -0.2) }.play;
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// used as an echo.
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{ BufCombL.ar(b.bufnum, Decay.ar(Dust.ar(1,0.5), 0.2, WhiteNoise.ar), 0.2, 3) }.play;
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::
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]
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