Description

Calculates the classical ADSR envelope

Syntax

ares xadsr iatt, idec, islev, irel [, idel]

kres xadsr iatt, idec, islev, irel [, idel]

Initialization

iatt -- duration of attack phase

idec -- duration of decay

islev -- level for sustain phase

irel -- duration of release phase

idel -- period of zero before the envelope starts

Performance

The envelope generated is the range 0 to 1 and may need to be scaled further, depending on the amplitude required. If using 0dbfs = 1, scaling down will probably be required since playing more than one note might result in clipping. If not using 0dbfs, scaling to a large amplitude (e.g. 32000) might be required.

The envelope may be described as:

Picture of an ADSR envelope.

The length of the sustain is calculated from the length of the note. This means xadsr is not suitable for use with MIDI events, use mxadsr instead. The opcode xadsr is identical to adsr except it uses exponential, rather than linear, line segments.

Examples

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

<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
-odac     ;;;realtime audio out
;-iadc    ;;;uncomment -iadc if RT audio input is needed too
; For Non-realtime ouput leave only the line below:
; -o xadsr.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

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

instr 1

iatt  = p5
idec  = p6  
islev = p7
irel  = p8

kenv	xadsr iatt, idec, islev, irel
kcps =  cpspch(p4) 	  ;frequency

asig	vco2  kenv * 0.8, kcps
	outs  asig, asig

endin

</CsInstruments>
<CsScore>

i 1  0  1  7.00  .0001  1  .01  .001 ; short attack
i 1  2  1  7.02  1  .5  .01  .001    ; long attack
i 1  4  2  6.09  .0001  1 .1  .7     ; long release

e
</CsScore>
</CsoundSynthesizer>

See Also

adsr, madsr, mxadsr

Credits

Author: John ffitch xadsr is new in Csound version 3.51.