The Alternative Csound Reference Manual
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# fold

fold -- Adds artificial foldover to an audio signal.

## Description

Adds artificial foldover to an audio signal.

## Syntax

ar fold asig, kincr

## Performance

asig -- input signal

kincr -- amount of foldover expressed in multiple of sampling rate. Must be >= 1

fold is an opcode which creates artificial foldover. For example, when kincr is equal to 1 with sr=44100, no foldover is added. When kincr is set to 2, the foldover is equivalent to a downsampling to 22050, when it is set to 4, to 11025 etc. Fractional values of kincr are possible, allowing a continuous variation of foldover amount. This can be used for a wide range of special effects.

## Examples

Here is an example of the fold opcode. It uses the files fold.orc and fold.sco.

Example 1. Example of the fold opcode.

    /* fold.orc */
    ; Initialize the global variables.
    sr = 44100
    kr = 4410
    ksmps = 10
    nchnls = 1

    ; Instrument #1.
    instr 1
      ; Use an ordinary sine wave.
      asig oscils 30000, 100, 1

      ; Vary the fold-over amount from 1 to 200.
      kincr line 1, p3, 200
      a1 fold asig, kincr

      out a1
    endin
    /* fold.orc */

    /* fold.sco */
    ; Play Instrument #1 for four seconds.
    i 1 0 4
    e
    /* fold.sco */

## Credits

Author: Gabriel Maldonado
Italy
1999

New in Csound version 3.56

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