94 lines
2.1 KiB
Text
94 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{BufAllpassN}
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Buffer based all pass delay line with no interpolation.@section{related}
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Classes/BufAllpassC, Classes/BufAllpassL, Classes/AllpassN
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@section{categories}
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UGens>Delays>Buffer
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@section{description}
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All pass delay line with no interpolation which uses a buffer for its
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internal memory. See also link::Classes/BufAllpassC:: which uses cubic
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interpolation, and which link::Classes/BufAllpassL:: uses linear
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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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// allocate buffer
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b = Buffer.alloc(s,44100,1);
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// Since the allpass delay has no audible effect as a resonator on
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// steady state sound ...
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{ BufAllpassC.ar(b.bufnum, WhiteNoise.ar(0.1), XLine.kr(0.0001, 0.01, 20), 0.2) }.play;
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// ...these examples add the input to the effected sound and compare variants so that you can hear
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// the effect of the phase comb:
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(
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{
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z = WhiteNoise.ar(0.2);
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z + BufAllpassN.ar(b.bufnum, z, XLine.kr(0.0001, 0.01, 20), 0.2)
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}.play)
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(
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{
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z = WhiteNoise.ar(0.2);
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z + BufAllpassL.ar(b.bufnum, z, XLine.kr(0.0001, 0.01, 20), 0.2)
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}.play)
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(
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{
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z = WhiteNoise.ar(0.2);
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z + BufAllpassC.ar(b.bufnum, z, XLine.kr(0.0001, 0.01, 20), 0.2)
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}.play)
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// used as an echo - doesn't really sound different than Comb,
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// but it outputs the input signal immediately (inverted) and the echoes
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// are lower in amplitude.
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{ BufAllpassN.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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