octave
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octave

octave — Calculates a factor to raise/lower a frequency by a given amount of octaves.

Description

Calculates a factor to raise/lower a frequency by a given amount of octaves.

Syntax

octave(x)

This function works at a-rate, i-rate, and k-rate.

Initialization

x -- a value expressed in octaves.

Performance

The value returned by the octave function is a factor. You can multiply a frequency by this factor to raise/lower it by the given amount of octaves.

Examples

Here is an example of the octave opcode. It uses the file octave.csd.

Example 282. Example of the octave 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
-odac           -iadc    ;;;RT audio I/O
; For Non-realtime ouput leave only the line below:
; -o octave.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
  ; The root note is A above middle-C (440 Hz)
  iroot = 440

  ; Raise the root note by two octaves.
  ioctaves = 2

  ; Calculate the new note.
  ifactor = octave(ioctaves)
  inew = iroot * ifactor

  ; Print out of all of the values.
  print iroot
  print ifactor
  print inew
endin


</CsInstruments>
<CsScore>

; Play Instrument #1 for one second.
i 1 0 1
e


</CsScore>
</CsoundSynthesizer>


Its output should include lines like: 

instr 1:  iroot = 440.000
instr 1:  ifactor = 4.000
instr 1:  inew = 1760.149

See Also

cent, db, semitone

Credits

Example written by Kevin Conder.

New in version 4.16

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