attack on envelope using slew (help)

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ansome
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attack on envelope using slew (help)

Post by ansome » Mon Jan 11, 2021 3:13 pm

I'm trying to make an attack decay envelope using a gate - trig converter into a slew with voltage control over attack and decay. when turning up the attack parameter it just reduces the over all output level of the envelope, I understand I'm just getting to change the attack from the start of the trigger to the end ( around 10ms) then the decay begins, my question is if I use the Galilean moons say in attack decay mode, when raising the attack it almost seems to extend the gate time giving a longer attack even though the gate doesn't change. is there a name or method for this? the attack function I have at the moment is basically pointless

what I want to happen
IMG_20210111_193859.jpg
what I'm getting
IMG_20210111_193922.jpg
one of many different configurations trying to get voltage controlled attack decay with shape control
Screenshot 2021-01-11 200624 (2).png
Edit- Just found this in the manual, any ideas how this is done?
Screenshot 2021-01-11 215403.png
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Last edited by ansome on Mon Jan 11, 2021 4:55 pm, edited 1 time in total.

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batchas
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Re: attack on envelope using slew (help)

Post by batchas » Mon Jan 11, 2021 4:30 pm

From the 2 scope photos you are posting, what you get is the inversion of what you want to happen. So you're not far from the solution isn't it?
I mean if I understand what you are doing, which is emulating a circuit, than you just need to invert the signal (and amplify it to get the same signal level) like with an inverting amp, to get what you want to happen, compared to what you get, or am I totally wrong?
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ansome
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Re: attack on envelope using slew (help)

Post by ansome » Mon Jan 11, 2021 4:38 pm

the first photo is another module, and its an exponential attack, not an inverted version of the bottom.

In the first photo ( hex inverts Galilean moons) seems like when I add attack even with just a trigger in, the attack knob is almost delaying the gate or making it longer to allow attack. where in my design the attack is limited to the triggers length and the more I turn it up it just turns the envelope down.
Last edited by ansome on Mon Jan 11, 2021 4:44 pm, edited 1 time in total.

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batchas
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Re: attack on envelope using slew (help)

Post by batchas » Mon Jan 11, 2021 4:39 pm

ansome wrote:
Mon Jan 11, 2021 4:38 pm
the first photo is another module, and its an exponential attack, not an inverted version of the bottom.
Okay. Sorry I was of no help :(
Well at least I gave my best :tu:
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FS: KESAKO Player & Reverb for Serge and Buchla

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ansome
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Re: attack on envelope using slew (help)

Post by ansome » Mon Jan 11, 2021 4:50 pm

:tu:
batchas wrote:
Mon Jan 11, 2021 4:39 pm
ansome wrote:
Mon Jan 11, 2021 4:38 pm
the first photo is another module, and its an exponential attack, not an inverted version of the bottom.
Okay. Sorry I was of no help :(
Well at least I gave my best :tu:

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ansome
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Re: attack on envelope using slew (help)

Post by ansome » Mon Jan 11, 2021 5:16 pm

is this even possible without microcontroller ? just looked under the hood of the module and it seems there is 2 pic18 micro controllers in there :doh:

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guest
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Re: attack on envelope using slew (help)

Post by guest » Mon Jan 11, 2021 5:43 pm

the way its done, is to have something that holds state (latch, flip flop, 555, schmitt trigger, etc) that goes high on the trigger rising edge, and holds the circuit in the attack phase until it reaches a set voltage, at which piont it drops it back to the decay phase. the exp/lin control is set with the feedback amount around the integrator.
openmusiclabs.com

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ansome
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Re: attack on envelope using slew (help)

Post by ansome » Mon Jan 11, 2021 6:01 pm

guest wrote:
Mon Jan 11, 2021 5:43 pm
the way its done, is to have something that holds state (latch, flip flop, 555, schmitt trigger, etc) that goes high on the trigger rising edge, and holds the circuit in the attack phase until it reaches a set voltage, at which piont it drops it back to the decay phase. the exp/lin control is set with the feedback amount around the integrator.
Thanks, is there any of examples online so I can try get my head around how it works? I did try another attack decay from Thomas Henry that used the 555 but had trouble adding cv control over attack and decay.

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guest
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Re: attack on envelope using slew (help)

Post by guest » Mon Jan 11, 2021 6:37 pm

heres a good writeup on it:

https://kassu2000.blogspot.com/2016/04/ ... rator.html

in this one, an opamp schmitt trigger is used to hold state. there are also a few extra bells and whistles on it.
openmusiclabs.com

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ansome
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Re: attack on envelope using slew (help)

Post by ansome » Mon Jan 11, 2021 6:46 pm

guest wrote:
Mon Jan 11, 2021 6:37 pm
heres a good writeup on it:

https://kassu2000.blogspot.com/2016/04/ ... rator.html

in this one, an opamp schmitt trigger is used to hold state. there are also a few extra bells and whistles on it.
Thanks, that was extremely help full :guinness:

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