transeg

Constructs a user-definable envelope.

Syntax

ModernClassic

ares = transeg(ia, idur, itype, ib [, idur2] [, itype] [, ic] ...)
kres = transeg(ia, idur, itype, ib [, idur2] [, itype] [, ic] ...)

ares transeg ia, idur, itype, ib [, idur2] [, itype] [, ic] ...
kres transeg ia, idur, itype, ib [, idur2] [, itype] [, ic] ...

Initialization

ia -- starting value.

ib, ic, etc. -- value after idur seconds.

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

idur2,... idurx etc. -- duration in seconds of segment

itype, itype2, etc. -- if 0, a straight line is produced. If non-zero, then transeg creates the following curve, for n steps:

ibeg + (ivalue - ibeg) * (1 - exp( i*itype/(n-1) )) / (1 - exp(itype))

Performance

If itype > 0, there is a slowly rising (concave) or slowly decaying (convex) curve, while if itype < 0, the curve is fast rising (convex) or fast decaying (concave). See also GEN16.

Examples

Here is an example of the transeg opcode. It uses the file transeg.csd. The example produces the following output:

Example of the transeg opcode.
<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 transeg.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

sr = 44100
ksmps = 128
nchnls = 2

0dbfs = 1

instr 1
;p4 and p5 determine the type of curve for each
;section of the envelope
kenv transeg 0.01, p3*0.25, p4, 1, p3*0.75, p5, 0.01
a1 oscil kenv, 440, 1
outs a1, a1
endin

</CsInstruments>
<CsScore>
; Table #1, a sine wave.
f 1 0 16384 10 1

i 1 0 2 2 2
i 1 + . 5 5
i 1 + . 1 1
i 1 + . 0 0
i 1 + . -2 -2
i 1 + . -2 2
i 1 + . 2 -2
e
</CsScore>
</CsoundSynthesizer>

Credits

Author: John ffitch
University of Bath, Codemist. Ltd.
Bath, UK
October 2000

New in Csound version 4.09

Thanks goes to Matt Gerassimoff for pointing out the correct command syntax.