fold — Adds artificial foldover to an audio signal.
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.
Here is an example of the fold opcode. It uses the file fold.csd.
Example 157. Example of the fold opcode.
See the sections Real-time Audio and Command Line Flags for more information on using command line flags.
<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
; Audio out Audio in No messages
-odac -iadc -d ;;;RT audio I/O
; For Non-realtime ouput leave only the line below:
; -o fold.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>
; 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
</CsInstruments>
<CsScore>
; Play Instrument #1 for four seconds.
i 1 0 4
e
</CsScore>
</CsoundSynthesizer>