The other night I started musing about how one might model an analog modular
synth in Csound. In trying to model an envelope generator, I find myself
puzzled. I'm sure there must be an easy way to do it, using reinit or
something....

The desiderata:

1) The "envelope generator module" is an instrument unto itself. It sends
its output via a global k-rate variable.

2) This instrument is "always on" while the score is playing. It doesn't
start and stop in response to i statements.

3) The envelope starts each time a global trigger signal goes from 0 to 1.
(Maybe later it will be gated rather than triggered. That's a refinement I'm
not yet ready to tackle.) If a new trigger is received before it finishes
moving through its segments, it starts over from the beginning.

4) The envelope does not loop. It cycles through once, reaches its end
value, and stays at the end value unless and until a new trigger is
received.

The thing is, the only envelope generator I've been able to find in Csound
that accepts a trigger input is looptseg ... and I don't want a looping
envelope.

I've tried using reinit, but I can't figure out how to make a reinit pass
restart a linseg again from the beginning of its defined contour.

Am I approaching it all wrong? How would the experts do this? Thanks in
advance!

--Jim Aikin

Something I've wanted for a long time is an envelope that has the
ability to retrigger, usually I've wanted it for reading soundfile
data from an ftable. The best solution I've found involves using
syncphasor, and holding the phase at zero with the sync inlet, its not
at all elegant, but it works. Heres a csd where I use this for
envelope generation, see the 'trigphasor' udo. This only creates the
phase, I use a table look up to make it an envelope.

Regards,
 Joel

On 10 November 2010 09:37,   wrote:
> I guess this can be done either with an always on instrument or with a UDO.
> I have done a similar thing before using a midi note on as a trigger, I will
> look
> for the CSD.
>
> Victor
>
> ----- Original Message -----
> From: Jim Aikin 
> Date: Wednesday, November 10, 2010 5:12 am
> Subject: [Csnd] Modeling an Analog Envelope
> To: csound@lists.bath.ac.uk
>
>>
>> The other night I started musing about how one might model an
>> analog modular
>> synth in Csound. In trying to model an envelope generator, I
>> find myself
>> puzzled. I'm sure there must be an easy way to do it, using
>> reinit or
>> something....
>>
>> The desiderata:
>>
>> 1) The "envelope generator module" is an instrument unto itself.
>> It sends
>> its output via a global k-rate variable.
>>
>> 2) This instrument is "always on" while the score is playing. It
>> doesn'tstart and stop in response to i statements.
>>
>> 3) The envelope starts each time a global trigger signal goes
>> from 0 to 1.
>> (Maybe later it will be gated rather than triggered. That's a
>> refinement I'm
>> not yet ready to tackle.) If a new trigger is received before it
>> finishesmoving through its segments, it starts over from the
>> beginning.
>> 4) The envelope does not loop. It cycles through once, reaches
>> its end
>> value, and stays at the end value unless and until a new trigger is
>> received.
>>
>> The thing is, the only envelope generator I've been able to find
>> in Csound
>> that accepts a trigger input is looptseg ... and I don't want a
>> loopingenvelope.
>>
>> I've tried using reinit, but I can't figure out how to make a
>> reinit pass
>> restart a linseg again from the beginning of its defined contour.
>>
>> Am I approaching it all wrong? How would the experts do this?
>> Thanks in
>> advance!
>>
>> --Jim Aikin
>> --
>> View this message in context:
>> http://csound.1045644.n5.nabble.com/Modeling-an-Analog-Envelope-
>> tp3258152p3258152.htmlSent from the Csound - General mailing
>> list archive at Nabble.com.
>>
>>
>> Send bugs reports to the Sourceforge bug tracker
>>             https://sourceforge.net/tracker/?group_id=81968&atid=564599
>> Discussions of bugs and features can be posted here
>> To unsubscribe, send email sympa@lists.bath.ac.uk with body
>> "unsubscribe csound"
>>
>
> Dr Victor Lazzarini, Senior Lecturer, Dept. of Music,
> National University of Ireland, Maynooth
>

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The solution I found is not entirely elegant, but it works. I created an
always-on "envelope generator generator" instrument, which contains very
little other than an event opcode. When the trigger signal goes to 1, the
generator generator shuts off any existing instances of the envelope
generator instrument and starts a new one. Each envelope generator gets its
level 0 value from the current output level (which is a global variable), so
there shouldn't be any discontinuities in the output.

It seems to me that a whole set of retriggering contour generators
(linsegre, linsegrer, etc.) would be a nice addition to Csound. I'm not
competent to create these myself, or I'd give it a try. The challenge,
perhaps, would be to define the behavior that the contour exhibits when a
new trigger is received. Does it jump back to level 0, thus introducing a
discontinuity in the output? That seems undesirable in many cases, but
sometimes it may be what one would want, so a mode parameter would be
needed.

--JA

My design for an ADSD  would be this:

opcode ADSD,k,iiiik
  imax,iatt,idec,isus,ktrig    xin

  ktime init 0
  kv init 0
  iper = 1/kr

  if (ktrig == 1) then
    ktime = ktime + iper
    if ktime < iatt then
      kt  = iatt
      kv = imax
    else
      kt = idec
      kv = isus
    endif
  else
    kv = 0
    ktime = 0
  endif

  kenv  portk  kv, kt
             xout  kenv

endop

For example, to demonstrate that this works, run this instrument for >  
6 seconds.

instr 1
    ktrig init 1
    kti timeinsts

    if kti < 2 then
       ktrig = 1
    elseif kti < 4 then
       ktrig = 0
    elseif kti < 6 then
       ktrig = 1
    else
       ktrig = 0
    endif

   k1 ADSD 1,0.01,0.1,0.8, ktrig
   a1 vco2 k1, 440
        out a1
endin

When ktrig is high, the envelope runs from Attack-Decay and holds sus,
when ktrig is low it goes to zero in Decay seconds and stays there.

Regards

Victor

On 10 Nov 2010, at 16:07, Jim Aikin wrote:

>
> The solution I found is not entirely elegant, but it works. I  
> created an
> always-on "envelope generator generator" instrument, which contains  
> very
> little other than an event opcode. When the trigger signal goes to  
> 1, the
> generator generator shuts off any existing instances of the envelope
> generator instrument and starts a new one. Each envelope generator  
> gets its
> level 0 value from the current output level (which is a global  
> variable), so
> there shouldn't be any discontinuities in the output.
>
> It seems to me that a whole set of retriggering contour generators
> (linsegre, linsegrer, etc.) would be a nice addition to Csound. I'm  
> not
> competent to create these myself, or I'd give it a try. The challenge,
> perhaps, would be to define the behavior that the contour exhibits  
> when a
> new trigger is received. Does it jump back to level 0, thus  
> introducing a
> discontinuity in the output? That seems undesirable in many cases, but
> sometimes it may be what one would want, so a mode parameter would be
> needed.
>
> --JA
>
> -- 
> View this message in context: http://csound.1045644.n5.nabble.com/Modeling-an-Analog-Envelope-tp3258152p3258924.html
> Sent from the Csound - General mailing list archive at Nabble.com.
>
>
> Send bugs reports to the Sourceforge bug tracker
>            https://sourceforge.net/tracker/?group_id=81968&atid=564599
> Discussions of bugs and features can be posted here
> To unsubscribe, send email sympa@lists.bath.ac.uk with body  
> "unsubscribe csound"
>



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Jim,

I don't see what's not elegant about your solution.

On a related subject, you may be aware that if you use turnoff2 to  
shut down instruments, it's wise for the instrument that issues the  
turnoff2 opcode to have a higher number than the instruments it's  
turning off. I don't know if this applies to using turnoff.

best,
Lou Cohen


On Nov 10, 2010, at 11:07 AM, Jim Aikin wrote:

>
> The solution I found is not entirely elegant, but it works. I  
> created an
> always-on "envelope generator generator" instrument, which contains  
> very
> little other than an event opcode. When the trigger signal goes to  
> 1, the
> generator generator shuts off any existing instances of the envelope
> generator instrument and starts a new one. Each envelope generator  
> gets its
> level 0 value from the current output level (which is a global  
> variable), so
> there shouldn't be any discontinuities in the output.
>
> It seems to me that a whole set of retriggering contour generators
> (linsegre, linsegrer, etc.) would be a nice addition to Csound. I'm  
> not
> competent to create these myself, or I'd give it a try. The challenge,
> perhaps, would be to define the behavior that the contour exhibits  
> when a
> new trigger is received. Does it jump back to level 0, thus  
> introducing a
> discontinuity in the output? That seems undesirable in many cases, but
> sometimes it may be what one would want, so a mode parameter would be
> needed.
>
> --JA
>
> -- 
> View this message in context: http://csound.1045644.n5.nabble.com/Modeling-an-Analog-Envelope-tp3258152p3258924.html
> Sent from the Csound - General mailing list archive at Nabble.com.
>
>
> Send bugs reports to the Sourceforge bug tracker
>            https://sourceforge.net/tracker/?group_id=81968&atid=564599
> Discussions of bugs and features can be posted here
> To unsubscribe, send email sympa@lists.bath.ac.uk with body  
> "unsubscribe csound"
>



Send bugs reports to the Sourceforge bug tracker
            https://sourceforge.net/tracker/?group_id=81968&atid=564599
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this works for me. in my case, the trigger is a button widget in  
qutecsound. best regards - joachim




0dbfs = 1

instr 1
env:
kenv    linseg  0, 1, 1, 1, 1, 1, 0
         rireturn
ktrig   invalue "trig"
  if ktrig == 1 then
         reinit  env
  endif
asin    oscils .2, 400, 0
aout    =      kenv * asin
         out    aout
endin



i 1 0 100



Am 10.11.2010 um 06:11 schrieb Jim Aikin:

>
> The other night I started musing about how one might model an analog  
> modular
> synth in Csound. In trying to model an envelope generator, I find  
> myself
> puzzled. I'm sure there must be an easy way to do it, using reinit or
> something....
>
> The desiderata:
>
> 1) The "envelope generator module" is an instrument unto itself. It  
> sends
> its output via a global k-rate variable.
>
> 2) This instrument is "always on" while the score is playing. It  
> doesn't
> start and stop in response to i statements.
>
> 3) The envelope starts each time a global trigger signal goes from 0  
> to 1.
> (Maybe later it will be gated rather than triggered. That's a  
> refinement I'm
> not yet ready to tackle.) If a new trigger is received before it  
> finishes
> moving through its segments, it starts over from the beginning.
>
> 4) The envelope does not loop. It cycles through once, reaches its end
> value, and stays at the end value unless and until a new trigger is
> received.
>
> The thing is, the only envelope generator I've been able to find in  
> Csound
> that accepts a trigger input is looptseg ... and I don't want a  
> looping
> envelope.
>
> I've tried using reinit, but I can't figure out how to make a reinit  
> pass
> restart a linseg again from the beginning of its defined contour.
>
> Am I approaching it all wrong? How would the experts do this? Thanks  
> in
> advance!
>
> --Jim Aikin
> -- 
> View this message in context: http://csound.1045644.n5.nabble.com/Modeling-an-Analog-Envelope-tp3258152p3258152.html
> Sent from the Csound - General mailing list archive at Nabble.com.
>
>
> Send bugs reports to the Sourceforge bug tracker
>            https://sourceforge.net/tracker/?group_id=81968&atid=564599
> Discussions of bugs and features can be posted here
> To unsubscribe, send email sympa@lists.bath.ac.uk with body  
> "unsubscribe csound"
>
>



Send bugs reports to the Sourceforge bug tracker
            https://sourceforge.net/tracker/?group_id=81968&atid=564599
Discussions of bugs and features can be posted here
To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe csound"