Fast decaying Envelope for Filter or VCA

[Zveeen]

Greetings all,

I am currently trying to build an effect that shortens the decay of the note being played, either with a Filter or a VCA. I really hoped the E&MM String Damper was the solution, but after messing around with it for quite some time I couldn't make it work.
I also read that quite a few People had problems with this circuit. I also had a look at the Maestro ME-1, but it wasn't working either. Now im looking into the EHX attack decay, wich is a way more complex design than the String Damper. I "just" want something to make every note staccato.
Does any of you know a circuit that might do the trick.

Thanks in advance,
stay safe

[Matthew Sanford]

I made Christine by The Tone God, and with high power starve (big resistance from 4049 to ground) it's very staccato. It's distortion, so not sure it's what you're looking for, but putting resistance in that way may achieve what you want. I'm sure there are much better ways, just two ¢s, this...

[Zveeen]

Sounds interesting,
I also modified a FF Once to be very compressed and staccato like, wich was very cool. But what I need is essentially a control voltage that has a variable decay time that occures after ideally every pluck of a string. Wich is why I'm afraid that the circuit of the EHX Attack Decay would be the best circuit to achieve such thing. With this CV from the Attack Decay circuit I want to control the cutoff point of a VCF, to make it very Synth like.
I wonder if the BBD is necessary if the circuit is used this way.
Has anyone messed with the attack decay ,,envelope circuit" yet?

[ElectricDruid]

It sounds like you're looking for something that triggers a simple decay envelope, or perhaps an Attack-Decay envelope. That doesn't sound too difficult, although I don't remember anything that's exactly that off the top of my head. It'd have a "Threshold" control for the trigger point, and then a "Decay" control for the output envelope time. The envelope is the easy bit, since it's just an RC decay. Getting reliable triggers from a guitar signal is harder, and requires some fairly clean playing, but it's not impossible.

Once you've got the envelope, feeding it to a VCA or VCF to cut the notes off is the easy bit, since there are loads of design for those parts flying around.

The triggering part is almost one of those "Sound to Light" circuits from back in the day that flashed a lamp when the kick drum hit. The basic outline is an envelope follower fed into a comparator. That makes the distinction between "no signal" and "signal".

I'll go and have dig in the archives and see if I can find anything suitable...

[Zveeen]

Yes, a trigger is basically all I need, but is also what is hardest to get, at leats a short reliable one that doesn't  retrigger. I once dug out the so called AMS-100 designed by none other than Craig Anderton himself, that got published in an DEVICE Magazine. It essentially feeds two envelopes into a comparator.
One Envelope has a fast attack time and the other one a slow one. The slower one also has an offset voltage, so that at the beginning of every note the comparator switches hi until the slow envelope with the offset voltage catches up, causing the comparator to switch low. Wich sounds actually quite genius, maybe cause it kinda is. But the article states it has an audible rise/delay to it wich causes klicking when a new attack period begins.It is the exact same problem EHX tackles in the Attack Decay with the BBD.........
 But as I think about it, schouldnˋt when used to trigger a Filter the klick be cutoff by the filter, since the vcf only opens up when the actual trigger envelope is active?

Maybe I should try it after all, what do you think?

[Zveeen]

I was thinking......... considering that I only want a faster decay from my Signal envelope. Shouldn't a highpass filter / Differentiator after the envelope detector do the trick. Or am I missing something. Its even simpler
than the String Damper, but it could be sufficient, since I am only interested in the decay part of it.

What do you think?

[Mark Hammer]

I find fast decays generally ted to make something sound more "synth-like".  Not that synths necessarily always use fast decays, but fast decays tend to sidestep more perceptible issues like envelope ripple, such that there is less of the audible imperfections coming from an electromechanical source.

[Zveeen]

Synth like is really what Im going for here. After all I am building an envelope filter with the 303 Filter core . But the filter core is only one part of the sound. It really is the fast snappy logarithmic decay of the envelope that makes the 303 sound. With just the Ladder filter and a normal envelope controlling it, it sounds like any other envelope filter. Maybe a tad more resonant, wich was a bit of a disappointment at first. The 303 uses a decay envelope that has diodes in series with the discharging resistor, to make it more logarithmic.