xadsr

xadsr — Calculates the classical ADSR envelope.

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 exponential ADSR envelope.

Picture of an exponential 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.

Example 1221. Example of the xadsr opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

<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>


Here is an example for the adsr-group, comparing the different adsr opcodes. It uses the file adsr-group.csd.

Example 1222. Example of the adsr group.

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

; by Menno Knevel - 2021

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

; both amplitude and filter use same ADSR curves 
instr 1		 	 
kenv	adsr	.01, .5, .5, p4    	; linear envelope 
asig	vco2	kenv, 110			; A+D+S+R = p3 	
asig	rezzy	asig, 500+(kenv*1000), 10	; same curve but scaled 
		outs	asig, asig	 
endin

instr 2	; midi behavior	 	 	 
kenv	madsr	.01, .5, .5, p4		; linear envelope
asig	vco2	kenv, 110			; A+D+S = p3, then go into Release stage 		
asig	rezzy	asig, 500+(kenv*1000), 10	; same curve but scaled  
		outs	asig, asig			
endin

instr 3 	 	 
kenv	xadsr	.01, .5 , .5, p4    ; exponential envelope
asig	vco2	kenv, 110			; A+D+S+R = p3 	 
asig	rezzy	asig, 500+(kenv*1000), 10	; same curve but scaled 
		outs	asig, asig
endin

instr 4	; midi behavior 	 
kenv	mxadsr	.01, .5 , .5, p4	; exponential envelope
asig	vco2	kenv, 110			; A+D+S = p3, then go into Release stage 	 
asig	rezzy	asig, 500+(kenv*1000), 10	; same curve but scaled 
		outs	asig, asig			
endin

</CsInstruments>
<CsScore>
s
i1 1 2 .01	; same notes for everyone!
i1 5 . .5
i1 9 . 1.5
s
i2 1 2 .01
i2 5 . .5
i2 9 . 1.5
s
i3 1 2 .01
i3 5 . .5
i3 9 . 1.5
s
i4 1 2 .01
i4 5 . .5
i4 9 . 1.5
e
</CsScore>
</CsoundSynthesizer>


See Also

adsr, madsr, mxadsr

Credits

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