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