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 534. 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
-odac      ;;;realtime audio out
;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
; For Non-realtime ouput leave only the line below:
; -o octave.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

sr = 44100
ksmps = 32
nchnls = 2
0dbfs  = 1

instr 1

iroot = 440		; root note is A above middle-C (440 Hz)
koct  lfo 5, 1, 5	; generate sawtooth, go from 5 octaves higher to root
koc = int(koct)		; produce only whole numbers
kfactor = octave(koc)	; for octave
knew = iroot * kfactor
printk2 knew

asig pluck 1, knew, 1000, 0, 1 
asig dcblock asig	;remove DC
     outs asig, asig

endin
</CsInstruments>
<CsScore>

i 1 0 5
e

</CsScore>
</CsoundSynthesizer>


Its output should include lines like:

 i1  3520.00000
 i1  1760.00000
 i1   880.00000
 i1   440.00000
 i1  7040.00000
 i1  3520.00000
 i1  1760.00000
 i1   880.00000
 i1   440.00000
 .......

See Also

cent, db, semitone

Credits

New in version 4.16