mxadsr

mxadsr — Calculates the classical ADSR envelope using the expsegr mechanism.

Description

Calculates the classical ADSR envelope using the expsegr mechanism.

Syntax

ares mxadsr iatt, idec, islev, irel [, idel] [, ireltim]
kres mxadsr iatt, idec, islev, irel [, idel] [, ireltim]

Initialization

iatt -- duration of attack phase

idec -- duration of decay

islev -- level for sustain phase

irel -- duration of release phase

idel (optional, default=0) -- period of zero before the envelope starts

ireltim (optional, default=-1) -- Control release time after receiving a MIDI noteoff event. If less than zero, the longest release time given in the current instrument is used. If zero or more, the given value will be used for release time. Its default value is -1. (New in Csound 3.59 - not yet properly tested)

Performance

The envelope is in the range 0 to 1 and may need to be scaled further. 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 adsr is not suitable for use with MIDI events. The opcode madsr uses the linsegr mechanism, and so can be used in MIDI applications. The opcode mxadsr is identical to madsr except it uses exponential, rather than linear, line segments.

You can use other pre-made envelopes which start a release segment upon receiving a note off message, like linsegr and expsegr, or you can construct more complex envelopes using xtratim and release. Note that you do not need to use xtratim if you are using mxadsr, since the time is extended automatically.

mxadsr is new in Csound version 3.51.

Examples

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

Example 639. Example of the mxadsr 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  -m0  --midi-key=4 --midi-velocity-amp=5 ; treat p4 and p5 as midi data
; For Non-realtime ouput leave only the line below:
; -o mxadsr-2.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

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

; by Menno Knevel - 2021

instr 1	                              ; use score and treat p4 and p5 as midi data
icps    = cpsmidinn(p4)               ; take midi note (p4) from score
iveloc  ampmidid p5, 92               ; take velocity (p5) from score
;               att, dec, lvl, release
kenv    mxadsr  .001, .2,   1,    p6 
prints  "duration of note (%ds) + release (%2.1fs)\\n", p3, p6                ; 
asig    vco2	iveloc, icps
asig    butlp	asig, 2000 
		outs    asig*kenv, asig*kenv

endin
</CsInstruments>
<CsScore>
;      note vel release	
s
i 1 0 1 62  60	0
i 1 2 1 62  80	0	
i 1 4 1 62  100	0	
i 1 6 1 58  50	0
s
i 1 1 1 62  60	0
i 1 3 1 62  80	1	
i 1 5 1 62  100	3	
i 1 7 1 58  50	5
e
</CsScore>
</CsoundSynthesizer>


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

Example 640. 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

linsegr, expsegr, envlpxr, mxadsr, madsr, adsr, expon, expseg, expsega line, linseg, xtratim

Credits

Author: John ffitch

November 2002. Thanks to Rasmus Ekman, added documentation for the ireltim parameter.

November 2003. Thanks to Kanata Motohashi, fixed the link to the linsegr opcode.