115 lines
2.1 KiB
Text
115 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{Formlet}
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FOF-like filter.@section{related}
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Classes/RHPF, Classes/RLPF, Classes/Resonz, Classes/Ringz
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@section{categories}
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UGens>Filters>Linear
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@section{description}
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This is a resonant filter whose impulse response is like that of a sine
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wave with a link::Classes/Decay2:: envelope over it. It is possible to
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control the attacktime and decaytime.
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Formlet is equivalent to:
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@racketblock[
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Ringz(in, freq, decaytime) - Ringz(in, freq, attacktime)
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::
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The great advantage to this filter over FOF is that there is no limit to
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the number of overlapping grains since the grain is just the impulse
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response of the filter.
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]
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@section{Note}
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The amplitude of the resulting signal depends on the server's sample rate. See link::Classes/Ringz#Interaction with sample rate#Ringz: Interaction with sample rate:: for details.
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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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freq
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Resonant frequency in Hertz.
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@section{argument}
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attacktime
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60 dB attack time in seconds.
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@section{argument}
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decaytime
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60 dB decay time in seconds.
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@section{argument}
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mul
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@section{argument}
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add
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@section{discussion}
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Note that if attacktime == decaytime then the signal cancels out and if
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attacktime > decaytime then the impulse response is inverted.
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@section{Examples}
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@racketblock[
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{ Formlet.ar(Impulse.ar(20, 0.5), 1000, 0.01, 0.1) }.play;
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{ Formlet.ar(Blip.ar(XLine.kr(10,400,8), 1000, 0.1), 1000, 0.01, 0.1) }.play;
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(
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// modulating formant frequency
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{
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var in;
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in = Blip.ar(SinOsc.kr(5,0,20,300), 1000, 0.1);
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Formlet.ar(in, XLine.kr(1500,700,8), 0.005, 0.04);
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}.play;
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)
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(
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// mouse control of frequency and decay time.
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{
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var in;
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in = Blip.ar(SinOsc.kr(5,0,20,300), 1000, 0.1);
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Formlet.ar(in,
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MouseY.kr(700,2000,1),
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0.005, MouseX.kr(0.01,0.2,1));
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}.play;
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)
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(
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// mouse control of frequency and decay time.
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{
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var freq;
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freq = Formlet.kr(
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Dust.kr(10 ! 2),
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MouseY.kr(7,200,1),
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0.005, MouseX.kr(0.1,2,1)
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);
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SinOsc.ar(freq * 200 + [500, 600] - 100) * 0.2
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}.play;
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)
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::
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]
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