ia -- starting value. Zero is illegal for exponentials.
ib, ic, etc. -- value after dur1 seconds, etc. For exponentials, must be non-zero and must agree in sign with ia.
idur1 -- duration in seconds of first segment. A zero or negative value will cause all initialization to be skipped.
These units generate control or audio signals whose values can pass through 2 or more specified points. The sum of dur values 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 last-defined segment to continue on in the same direction.
Here is an example of the expon opcode. It uses the files expon.orc and expon.sco.
Example 1. Example of the expon opcode.
/* expon.orc */
/* Written by Kevin Conder */
; 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
/* expon.orc */
/* expon.sco */
/* Written by Kevin Conder */
; Table #1, a sine wave.
f 1 0 16384 10 1
; Play Instrument #1 for two seconds.
i 1 0 2
e
/* expon.sco */