112 lines
1.6 KiB
Text
112 lines
1.6 KiB
Text
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#lang scribble/manual
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@(require (for-label racket))
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@title{SOS}
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Second order filter section (biquad).@section{related}
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Classes/FOS
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@section{categories}
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UGens>Filters>Linear
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@section{description}
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A standard second order filter section. Filter coefficients are given
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directly rather than calculated for you. Formula is equivalent to:
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@racketblock[
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out(i) = (a0 * in(i)) + (a1 * in(i-1)) + (a2 * in(i-2)) + (b1 * out(i-1)) + (b2 * out(i-2))
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::
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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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signal input
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@section{argument}
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a0
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See formula above.
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@section{argument}
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a1
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See formula above.
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@section{argument}
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a2
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See formula above.
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@section{argument}
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b1
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See formula above.
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@section{argument}
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b2
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See formula above.
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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{Examples}
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@racketblock[
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// example: same as TwoPole
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(
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{
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var rho, theta, b1, b2;
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theta = MouseX.kr(0.2pi, pi);
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rho = MouseY.kr(0.6, 0.99);
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b1 = 2.0 * rho * cos(theta);
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b2 = rho.squared.neg;
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SOS.ar(LFSaw.ar(200, 0, 0.1), 1.0, 0.0, 0.0, b1, b2)
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}.play
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)
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(
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{
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var rho, theta, b1, b2;
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theta = MouseX.kr(0.2pi, pi);
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rho = MouseY.kr(0.6, 0.99);
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b1 = 2.0 * rho * cos(theta);
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b2 = rho.squared.neg;
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SOS.ar(WhiteNoise.ar(0.1 ! 2), 1.0, 0.0, 0.0, b1, b2)
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}.play
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)
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// example with SOS.kr kr as modulator
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(
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{
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var rho, theta, b1, b2, vib;
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theta = MouseX.kr(0.2pi, pi);
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rho = MouseY.kr(0.6, 0.99);
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b1 = 2.0 * rho * cos(theta);
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b2 = rho.squared.neg;
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vib = SOS.kr(LFSaw.kr(3.16), 1.0, 0.0, 0.0, b1, b2);
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SinOsc.ar( vib * 200 + 600) * 0.2
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}.play
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)
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::
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]
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