interpretor/preprocessor/faust-0.9.47mr3/tools/faust2pd/examples/synth/echo.dsp

   1
   2 /* Stereo delay with feedback. */
   3
   4 declare name "echo -- stereo delay effect";
   5 declare author "Albert Graef";
   6 declare version "1.0";
   7
   8 import("music.lib");
   9
  10 level           = hslider("level", 1, 0, 1, 0.01);
  11 dtime           = hslider("delay", 0.040, 0, 5, 0.001);
  12 feedback        = hslider("feedback", 0, 0, 1, 0.001);
  13 stereo          = hslider("stereo", 1, 0, 1, 0.001);
  14
  15 /* The stereo parameter controls the amount of stereo spread. For stereo=0 you
  16    get a plain delay, without crosstalk between the channels. For stereo=1 you
  17    get a pure ping-pong delay where the echos from the left first appear on
  18    the right channel and vice versa. Note that you'll hear the stereo effects
  19    only if the input signal already has some stereo spread to begin with; if
  20    necessary, you can just pan the input signal to the left or the right to
  21    achieve that. */
  22
  23 echo(dtime,level,feedback,stereo,x,y)
  24                 = f(x,y) // the echo loop
  25                 // mix
  26                 : (\(u,v).(x+level*(d(u)+c(v)),
  27                            y+level*(d(v)+c(u))))
  28                 // compensate for gain level
  29                 : (/(1+level), /(1+level))
  30 with {
  31         f       = g ~ (*(feedback),*(feedback));
  32         g(u,v,x,y)
  33                 = h(x+d(u)+c(v)), h(y+d(v)+c(u));
  34         h       = fdelay(1<<18, SR*dtime);
  35         c(x)    = x*stereo;
  36         d(x)    = x*(1-stereo);
  37 };
  38
  39 process         = vgroup("echo", echo(dtime,level,feedback,stereo));