Description

Trace an exponential curve between specified points.

Syntax

ares expon ia, idur, ib

kres expon ia, idur, ib

Initialization

ia -- starting value. Zero is illegal for exponentials.

ib -- value after idur seconds. For exponentials, must be non-zero and must agree in sign with ia.

idur -- duration in seconds of the segment. A zero or negative value will cause all initialization to be skipped.

Performance

These units generate control or audio signals whose values can pass through 2 specified points. The idur value may or may not equal the instrument's performance time: a shorter performance will truncate the specified pattern, while a longer one will cause the defined segment to continue on in the same direction.

Examples

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

<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 expon.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
  ; Define kcps as a frequency value that exponentially declines 
  ; from 880 to 220. It declines over the period set by p3.
  kcps expon 880, p3, 220

  a1 oscil 20000, kcps, 1
  out a1
endin


</CsInstruments>
<CsScore>

; Table #1, a sine wave.
f 1 0 16384 10 1

; Play Instrument #1 for two seconds.
i 1 0 2
e


</CsScore>
</CsoundSynthesizer>

See Also

expseg, expsegr, line, linseg, linsegr

Credits

Example written by Kevin Conder.