152 lines
3.8 KiB
Racket
152 lines
3.8 KiB
Racket
#lang scribble/manual
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@(require (for-label racket))
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@title{FreqShift}
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Frequency Shifter.@section{related}
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Classes/Hilbert, Classes/HilbertFIR
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@section{categories}
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UGens>Filters>Nonlinear, UGens>Filters>Pitch
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@section{description}
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FreqShift implements single sideband amplitude modulation, also known as
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frequency shifting, but not to be confused with pitch shifting. Frequency
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shifting moves all the components of a signal by a fixed amount but does
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not preserve the original harmonic relationships.
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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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in
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The input signal.
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@section{argument}
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freq
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Amount of shift in cycles per second.
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@section{argument}
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phase
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Phase of the frequency shift (0..2pi).
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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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// shifting a 100Hz tone by 1 Hz rising to 500Hz
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{FreqShift.ar(SinOsc.ar(100),XLine.kr(1,500,5),0,[0.1,0.1])}.play(s);
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// shifting a complex tone by 1 Hz rising to 500Hz
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{FreqShift.ar(Klang.ar(`[[101,303,606,808]]),XLine.kr(1,500,10),0,[0.1,0.1])}.play(s);
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// modulating shift and phase
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{FreqShift.ar(SinOsc.ar(10),LFNoise2.ar(0.3,1500),SinOsc.ar(500).range(0,2pi),[0.1,0.1])}.play(s);
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// the ubiquitous houston example
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(
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b = Buffer.read(s, Platform.resourceDir +/+ "sounds/a11wlk01.wav");
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{FreqShift.ar(PlayBuf.ar(1,b.bufnum,BufRateScale.kr(b.bufnum),loop:1),LFNoise0.kr(0.45,1000),0,[1,1])}.play(s);
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)
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// shifting bandpassed noise
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{FreqShift.ar(BPF.ar(WhiteNoise.ar(0.2),1000,0.001),LFNoise0.kr(5.5,1000),0,[32,32])}.play(s);
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::
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]
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@section{subsection}
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More Examples
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send a SynthDef, run the routine then send a different SynthDef
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@racketblock[
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(// simple detune & pitchmod via FreqShift
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SynthDef("frqShift1",{arg frq,detune=1.5;
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var e1,left,right;
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e1 = EnvGen.ar(Env.new([0,0.1,0],[1,2.3]),1,doneAction: Done.freeSelf);
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left = SinOsc.ar(frq,0,e1); // original tone
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left = left + FreqShift.ar(left,frq*detune); // shift and add back to original
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right = FreqShift.ar(left,SinOsc.kr(3.23,0,5));
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Out.ar(0, [left,right] * 0.1);
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}).add;
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)
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(// the routine
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r = Routine({
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var table,pitch;
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table = [0,2,4,5,7,9,11,12];
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inf.do{
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pitch = (48+(12*2.rand) + table.choose).midicps;
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Synth.grain(\frqShift1, [\frq, pitch]);
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3.wait;
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};
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};
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).play;
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)
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(// shift pulse wave in opposite directions
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SynthDef("frqShift1",{arg frq,detune=0.15;
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var e1,snd,left,right;
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e1 = EnvGen.ar(Env.new([0,1,0],[0.02,3.2]),1,doneAction: Done.freeSelf);
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snd = Pulse.ar(frq,SinOsc.kr(2.3).range(0.2,0.8),e1); // original tone
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left = FreqShift.ar(snd,XLine.kr(-0.1,-200,2)); // shift and add back to original
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right = FreqShift.ar(snd,XLine.kr(0.1,200,2));
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Out.ar(0, [left,right] * 0.1);
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}).add
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)
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(// FreqShift >> feedback >>> FreqShiftc
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SynthDef("frqShift1",{arg frq;
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var e1,snd,snd2,in;
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in = FreqShift.ar(InFeedback.ar(0,1)*3.2,XLine.ar(0.01,frq*1.5,1)); // shift the feedback
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e1 = Env.new([0,0.1,0],[0.02,2.98]);
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snd = SinOsc.ar(frq,0,EnvGen.ar(e1,1,doneAction: Done.freeSelf));
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snd2 = FreqShift.ar(snd+in,SinOsc.ar(4.24,0.5,3),0,0.5); // subtle modulating shift
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OffsetOut.ar([0,1], Limiter.ar(snd2+snd * 0.5,1,0.005));
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}).add;
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)
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(// ssllooww columbia tuned shift detune
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r.stop; // stop old routine
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Buffer.read(s, Platform.resourceDir +/+ "sounds/a11wlk01.wav", bufnum:99);
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SynthDef("frqShift1",{arg frq, bufnum;
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var e1,snd,left,right;
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e1 = Env.new([0,1,0],[3,1],-4);
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snd = PlayBuf.ar(1, bufnum, BufRateScale.kr(bufnum) * 0.01, loop:1);
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left = FreqShift.ar(snd,frq*2,0,EnvGen.ar(e1,1,doneAction: Done.freeSelf)); // subtle shift of the output
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right = FreqShift.ar(snd,frq*3,0,EnvGen.ar(e1,1,doneAction: Done.freeSelf));
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Out.ar(0, [left,right] * 3);
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}).add;
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(// the routine
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r = Routine({
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var table,pitch;
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table = [0,2,4,5,7,9,11,12];
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inf.do{
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pitch = (48+(12*2.rand) + table.choose).midicps;
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s.sendMsg("s_new","frqShift1",-1,1,1, "frq", pitch, "bufnum", 99);
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3.wait;
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};
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};
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).play;
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)
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::
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]
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