HelpSource/Classes/Convolution.schelp

   1 class:: Convolution
   2 summary:: Real-time convolver.
   3 related:: Classes/Convolution2, Classes/Convolution2L, Classes/Convolution3
   4 categories::  UGens>FFT, UGens>Convolution
   5
   6
   7 Description::
   8
   9 Strict convolution of two continuously changing inputs. Also see
  10 link::Classes/Convolution2::  for a cheaper CPU cost alternative for the
  11 case of a fixed kernel which can be changed with a trigger message.
  12
  13
  14 See also  link::http://www.dspguide.com/ch18.htm::  by Steven W.
  15 Smith.
  16
  17
  18 classmethods::
  19
  20 method::ar
  21
  22 argument::in
  23
  24 Processing target.
  25
  26
  27 argument::kernel
  28
  29 Processing kernel.
  30
  31
  32 argument::framesize
  33
  34 Size of FFT frame, must be a power of 2.
  35
  36
  37 argument::mul
  38
  39 Output will be multiplied by this value.
  40
  41
  42 argument::add
  43
  44 This value will be added to the output.
  45
  46
  47 Examples::
  48
  49 code::
  50 (
  51
  52         { var input, kernel;
  53
  54         input=AudioIn.ar(1);
  55         kernel= Mix.ar(LFSaw.ar([300,500,800,1000]*MouseX.kr(1.0,2.0),0,1.0));
  56
  57         //must have power of two framesize
  58         Out.ar(0,Convolution.ar(input,kernel, 1024, 0.5));
  59          }.play;
  60
  61 )
  62
  63 (
  64 //must have power of two framesize- FFT size will be sorted by Convolution to be double this
  65 //maximum is currently a=8192 for FFT of size 16384
  66 a=2048;
  67 s = Server.local;
  68 //kernel buffer
  69 g = Buffer.alloc(s,a,1);
  70 )
  71
  72 (
  73 //random impulse response
  74 g.set(0,1.0);
  75 100.do({arg i; g.set(a.rand, 1.0.rand)});
  76
  77
  78         { var input, kernel;
  79
  80         input=AudioIn.ar(1);
  81         kernel= PlayBuf.ar(1,g.bufnum,BufRateScale.kr(g.bufnum),1,0,1);
  82
  83         Out.ar(0,Convolution.ar(input,kernel, 2*a, 0.5));
  84          }.play;
  85
  86 )
  87 ::
  88