#lang scribble/manual
@(require (for-label racket))

@title{BufAllpassC}
 Buffer based all pass delay line with cubic interpolation.@section{related}
  Classes/BufAllpassL, Classes/BufAllpassN, Classes/AllpassC
@section{categories}
   UGens>Delays>Buffer


@section{description}


All pass delay line with cubic interpolation which uses a buffer for its
internal memory. See also  link::Classes/BufAllpassN::  which uses no
interpolation, and  which  link::Classes/BufAllpassL::  uses linear
interpolation. Cubic interpolation is more computationally expensive
than linear, but more accurate.


@section{classmethods}
 

@section{method}
 ar

@section{argument}
 buf
Buffer number.

@section{argument}
 in
The input signal.

@section{argument}
 delaytime
Delay time in seconds.

@section{argument}
 decaytime
Time for the echoes to decay by 60 decibels. If this time is negative then the feedback coefficient will be negative, thus emphasizing only odd harmonics at an octave lower.

@section{discussion}
 
@section{warning}
 
For reasons of efficiency, the effective buffer size is limited to the previous power of two. So, if 44100 samples are allocated, the maximum delay would be 32768 samples.
::

@section{Examples}
 


@racketblock[

// allocate buffer
b = Buffer.alloc(s,44100,1);

// Since the allpass delay has no audible effect as a resonator on
// steady state sound ...

{ BufAllpassC.ar(b.bufnum, WhiteNoise.ar(0.1), XLine.kr(0.0001, 0.01, 20), 0.2) }.play;

// ...these examples add the input to the effected sound and compare variants so that you can hear
// the effect of the phase comb:

(
{
	z = WhiteNoise.ar(0.2);
	z + BufAllpassN.ar(b.bufnum, z, XLine.kr(0.0001, 0.01, 20), 0.2)
}.play)

(
{
	z = WhiteNoise.ar(0.2);
	z + BufAllpassL.ar(b.bufnum, z, XLine.kr(0.0001, 0.01, 20), 0.2)
}.play)

(
{
	z = WhiteNoise.ar(0.2);
	z + BufAllpassC.ar(b.bufnum, z, XLine.kr(0.0001, 0.01, 20), 0.2)
}.play)

// used as an echo - doesn't really sound different than Comb,
// but it outputs the input signal immediately (inverted) and the echoes
// are lower in amplitude.
{ BufAllpassN.ar(b.bufnum, Decay.ar(Dust.ar(1,0.5), 0.2, WhiteNoise.ar), 0.2, 3) }.play;

::

]