rsc3/doc-schelp/HelpSource/Classes/FreqShift.schelp

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