58 lines
1.6 KiB
Racket
58 lines
1.6 KiB
Racket
#lang scribble/manual
|
|
@(require (for-label racket))
|
|
|
|
@title{BLowPass4}
|
|
24db/oct rolloff - 4th order resonant Low Pass Filter [1]@section{categories}
|
|
UGens>Filters>BEQSuite
|
|
@section{related}
|
|
Classes/SOS, Classes/BLowPass, Classes/BHiPass, Classes/BHiPass4, Classes/BPeakEQ, Classes/BLowShelf, Classes/BHiShelf, Classes/BBandPass, Classes/BBandStop, Classes/BAllPass
|
|
|
|
@section{description}
|
|
|
|
The B equalization suite is based on the Second Order Section (link::Classes/SOS::) biquad UGen.
|
|
|
|
@section{note}
|
|
|
|
Biquad coefficient calculations imply certain amount of CPU overhead. These plugin UGens contain optimizations such that the coefficients get updated only when there has been a change to one of the filter's parameters. This can cause spikes in CPU performance and should be considered when using several of these units.
|
|
::
|
|
|
|
[1] this is a composite pseudo link::Classes/UGen::. BLowPass4 is built by cascading 2 link::Classes/SOS:: sections.
|
|
|
|
@section{classmethods}
|
|
|
|
|
|
@section{method}
|
|
ar
|
|
@section{argument}
|
|
in
|
|
input signal to be processed.
|
|
@section{argument}
|
|
freq
|
|
cutoff frequency.
|
|
WARNING: due to the nature of its implementation frequency values close to 0 may cause glitches and/or extremely loud audio artifacts!
|
|
@section{argument}
|
|
rq
|
|
the reciprocal of Q. bandwidth / cutoffFreq.
|
|
@section{argument}
|
|
mul
|
|
@section{argument}
|
|
add
|
|
|
|
@section{examples}
|
|
|
|
|
|
@racketblock[
|
|
s.boot;
|
|
(
|
|
z = {
|
|
BLowPass4.ar(
|
|
SoundIn.ar([0,1]),
|
|
MouseX.kr(10, 20000, \exponential), // cutoff freq.
|
|
MouseY.kr(0.1, 1.0, \linear), // rq - compensate for 2 biquad sections.
|
|
0.5); // mul
|
|
}.play)
|
|
z.release;
|
|
::
|
|
]
|
|
|
|
|