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expsegb

Trace a series of exponential segments between specified absolute points.

Syntax

ares = expsegb(ia, itim1, ib [, itim2] [, ic] [...])
kres = expsegb(ia, itim1, ib [, itim2] [, ic] [...])

ares expsegb ia, itim1, ib [, itim2] [, ic] [...]
kres expsegb ia, itim1, ib [, itim2] [, ic] [...]

Initialization

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

ib, ic, etc. -- value at tim1 seconds, etc. For exponentials, must be non-zero and must agree in sign with ia.

itim1 -- time in seconds of end of first segment.

itim2, itim3, etc. -- time in seconds of subsequent ends of segments.

Performance

These units generate control or audio signals whose values can pass through 2 or more specified points. The last tim 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 last-defined segment to continue on in the same direction.

Note that the expsegb opcode does not operate correctly at audio rate when segments are shorter than a k-period. Try the expsegba opcode instead.

Examples

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

Example of the expsegb opcode.
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<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 expseg.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
  ; p4 = frequency in pitch-class notation.
  kcps = cpspch(p4)

  ; Create an amplitude envelope.
  kenv expsegb 0.01, p3*0.25, 1, p3, 0.01
  kamp = kenv * 30000

  a1 oscil kamp, kcps, 1
  out a1
endin


</CsInstruments>
<CsScore>

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

; Play Instrument #1 for a half-second, p4=8.00
i 1 0 0.5 8.00
; Play Instrument #1 for a half-second, p4=8.01
i 1 1 0.5 8.01
; Play Instrument #1 for a half-second, p4=8.02
i 1 2 0.5 8.02
; Play Instrument #1 for a half-second, p4=8.03
i 1 3 0.5 8.03
e


</CsScore>
</CsoundSynthesizer>

See also

Linear and Exponential Generators

Credits

Author: Victor Lazzarini
June 2011

New in version 5.14