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Buchla Music Easel Envelope Generator
MUFF WIGGLER Forum Index -> Buchla, EMS & Serge Goto page 1, 2  Next [all]
Author Buchla Music Easel Envelope Generator
sharema
Hi all,

i just got a music easel. I still have to explore it but i already have a question about the envelope: i am used to synths where the keyboard pressure triggers always the envelope even if the previous envelope still has to end its cycle. But from what i hear on my easel, here the envelope is not triggered again until the previous cycle is concluded. Is this normal?

Thanks!

Sharema
bournio
I don't own an easel.

But.

Have you tried moving the switches to different positions to see if you get the expected result?
sharema
Yes i tried. It is not that it does not work, but it works in its own way, i don't mean that it is bad but just not what i was waiting for..

It looks like the EG is in some way a kind of lfo, in wich you can shape the waveform (with ASD) and, until a cycle is completed, you can not retrigger it.

Just something different from all the synths i owned before..

No easel owners out there?

Thanks
studiokpg
I just took a look, and that seems to be true with long attacks, but not with long releases. Maybe the logic is it won't retrigger until the attack phase is complete.
bournio
My Euro 281 envelope generate will not retrigger in the attack phase. Have you tried with a long decay to see what happens?
vgermuse
sharema wrote:
Hi all,

i just got a music easel. I still have to explore it but i already have a question about the envelope: i am used to synths where the keyboard pressure triggers always the envelope even if the previous envelope still has to end its cycle. But from what i hear on my easel, here the envelope is not triggered again until the previous cycle is concluded. Is this normal?

Thanks!

Sharema


Hey Sharema,

Yep, normal behavior . . . no re-triggering with either Attack or Decay of the EG. If you use Pressure then the Envelope follows pressure and does re-trigger.
Here's how mine works, definitely old, old school :-)
https://www.hightail.com/download/cUJYTkFucVh0d0ZESjhUQw
sharema
Hey, thanks very much for answers and the explanatory video!

I will try it as soon as possible (probably and unfortunately not before the week end..)
skkatter
The Music Easel envelope is the thing I liked least about the BEMI one I had a loan of. Wasn't exact enough, felt like a lot of the slider positions weren't doing much, it felt sluggish. I ended up using the CV out from the Fenix and Serge envelopes going into the CV in of the Dual Low Pass Gates which worked a lot better.
sharema
I checked it out again and yes, its behaviour is not straight, but once you understand it you can use it at your advantage.

What i see is that the retrigger doesn't start if you are in the attack part of the ASD, but if you are in the decay it retriggers. That's the most "strange" thing for me. I have a korg MS10 that is old school (but less than the buchla.. around 1980 the MS10, 1974 the buchla).

So the main diffeence is: Whit the MS10, if i am in the Attack and i leave the key, the release starts (the MS10 is ADSR, so the release in the MS10 is the Decay of the buchla..), and if i press a key again it restarts the envelope shape starting from the level of the release (if i am still in the release part of course). With the buchla: to retrigger the envelope the attack has to be finished, if not the retrigger is ignored.

So with the buchla you can add polyrithms (uncorrelated) playing with an attack that is longer than the pulse rate or the sequencer rate, so in some way you can use it as an LFO.
softroom
I'm struggling to understand the envelopes too - my issue is with a permanent drone mode that kicks in with the sustain and decay at the values at or above those in the video here.

https://www.instagram.com/p/Bb656fTF9nv/?taken-by=smokyfrog

It doesn't matter whether I'm in sustain or transient mode - all settings below those tipping points on the sliders are pointless, the drone continues. My friend with an Easel confirms his does the same - but this behaviour seems to contradict the manual's explanation, unless there's something tucked away that I missed. I like to understand stuff.

Could an experienced user confirm whether this is 'normal' behaviour or I have a fault? Cheers.
InnnerSight
Mine is the same and we are not alone

https://www.muffwiggler.com/forum/viewtopic.php?t=144963&sid=97861718f 1669697fa6fae9fc9270762
softroom
InnnerSight wrote:
Mine is the same and we are not alone

https://www.muffwiggler.com/forum/viewtopic.php?t=144963&sid=97861718f 1669697fa6fae9fc9270762


It's a bit weird to have so much slider travel that achieves nothing. Oh well. Thanks for checking.
InnnerSight
softroom wrote:
InnnerSight wrote:
Mine is the same and we are not alone

https://www.muffwiggler.com/forum/viewtopic.php?t=144963&sid=97861718f 1669697fa6fae9fc9270762


It's a bit weird to have so much slider travel that achieves nothing. Oh well. Thanks for checking.


The slider travel works but there is just an odd relationship between sustain and decay which causes the envelope to stay open.
I can have an attack and sustain each of 10s OR an attack and decay each of 10s, but not a sustain and decay of 10s at the same time.
I can get certain ratios of them, but its like the decay cannot be more the inverse slider position of the sustain - at least thats what my experiments suggest.
InnnerSight
It makes me wonder if it is linked to the circuit that the Sustained switch uses?

Makes we want to hunt down a circuit diagram for it.
softroom
InnnerSight wrote:
It makes me wonder if it is linked to the circuit that the Sustained switch uses?

Makes we want to hunt down a circuit diagram for it.


The bits they added may well be the issue, especially since the MIDI is so half-arsed. I find it hard to believe Don Buchla would have done it this way. Anyone with an original confirm equivalent behaviour?
wsy
Testing refiring the EG on a recent (BEMI) easel - yes, you can "restart" the envelope.

Switches: upper to "keyboard", lower to "transient".

Sliders: attack and decay both to halfway between 3.5 and 10, and Sustain to 0.002. Patch pulse to pulse, pressure to pressure, and pitch to pitch

I have no trouble - hit a note, and it swells and decays over several seconds. hit again, and it immediately swells back to full
and then decays again without going thru zero. Yes, the process can be repeated, no problem.

Yes, I do have the issue of if the sum of Sustain and Decay is more than halfway down, sustain never ends - but that's actually
useful as you can then use that to make a "latch" that waits for an inverted gate... at least that's the idea at least, though I don't think
you can actually do so without using a program card.

And to be honest, I'd prefer it it was otherwise, so if you get a fix, let me know!

- Bill
softroom
wsy wrote:


Yes, I do have the issue of if the sum of Sustain and Decay is more than halfway down, sustain never ends - but that's actually
useful as you can then use that to make a "latch" that waits for an inverted gate... at least that's the idea at least, though I don't think
you can actually do so without using a program card.

And to be honest, I'd prefer it it was otherwise, so if you get a fix, let me know!

- Bill


Will do. I got the aux card rather than the program card - because I wanted CV control over envelope times. I'm an envelope bore, ask any of my friends. But the general envelope handling makes CV access to each stage less exciting than it could be. I will let you know if I sort something or get a definitive answer. (There's much to like about this synth so I'm not giving up over a few shortcomings that are, hopefully, fixable. Or at least explainable).
tarandfeathers
InnnerSight wrote:
softroom wrote:
InnnerSight wrote:
Mine is the same and we are not alone

https://www.muffwiggler.com/forum/viewtopic.php?t=144963&sid=97861718f 1669697fa6fae9fc9270762


It's a bit weird to have so much slider travel that achieves nothing. Oh well. Thanks for checking.


The slider travel works but there is just an odd relationship between sustain and decay which causes the envelope to stay open.
I can have an attack and sustain each of 10s OR an attack and decay each of 10s, but not a sustain and decay of 10s at the same time.
I can get certain ratios of them, but its like the decay cannot be more the inverse slider position of the sustain - at least thats what my experiments suggest.


This behaviour is the result of an attempt to fix another fault with the envelope generator, where if the envelope is used in sustained mode it would not sustain indefinitely unless the sustain slider was above a certain setting. In the original 70s easel a feedback capacitor was added which is supposed to send a pulse of current into the envelope integrator when the envelope moved from the sustain phase to the decay phase, which goes some way towards making the sustain mode work properly. A side effect is this effect where long settings of sustain/decay in combination cause the envelope to latch open.

I made a daughterboard for the v2 and v2.1 Roman Filipov easel clones that fixes both these issues:

http://www.dunningtonaudio.co.uk/product/music-easel-infinite-sustain- module/

I also have a half written article analysing the envelope circuit and explaining why it doesn't work and how my fix works. It's not tremendously complicated but I suspect that production numbers of the original 208 module were so low that Buchla did not consider it worth the investment to fix. I'm not sure why it was not resolved when BEMI reissued the easel, other than maybe someone thought Don intended it to work like that. I am 99% certain that he did not but that the design was very much not finalised when the easel was released and then it was never a priority to make it work.

I will finish the article and publish it at some point in the next month, hopefully.

Theoretically you could add one of my cards to a BEMI easel but it would be very fiddly and I don't have a BEMI to test with so I cannot provide any support in that regard, you'd have to have a good idea what you were doing and be pretty competent with SMD rework to make it happen. I have no idea what a good way to mount the board mechanically in a BEMI easel would be.

TLDR - the envelope isn't intended to work that way, but it does in all easels, it's a design flaw, not a fault with an individual unit. It's fixable but probably not in a BEMI easel.
InnnerSight
I look forward to reading your article - sounds cool.
softroom
Continuing on this theme, I'm still puzzled by sustain mode, which doesn't seem to work as the manual says it should. The manual says:

"In ‘sustained’ mode the duration will depend on the length of the applied trigger. Upon reception of a trigger the envelope voltage will rise according to the ‘attack’ time setting, sustain as long as the trigger pulse is active, and will enter the ‘decay’ portion of the cycle when the trigger is released."

This doesn't happen on this one. The Sustain time is only set by the sustain value (except when it goes into drone as previously discussed) in either mode. Really makes it less expressive to play. Unless the keyboard only sends triggers, not gates?

Never had a synth make me feel quite so dumb wink
wsy
softroom wrote:
Continuing on this theme, I'm still puzzled by sustain mode, which doesn't seem to work as the manual says it should. The manual says:

"In ‘sustained’ mode the duration will depend on the length of the applied trigger. Upon reception of a trigger the envelope voltage will rise according to the ‘attack’ time setting, sustain as long as the trigger pulse is active, and will enter the ‘decay’ portion of the cycle when the trigger is released."

This doesn't happen on this one. The Sustain time is only set by the sustain value (except when it goes into drone as previously discussed) in either mode. Really makes it less expressive to play. Unless the keyboard only sends triggers, not gates?

Never had a synth make me feel quite so dumb wink


Try setting the EG switches / sliders like this:

---- Upper switch away from you ("keyboard")
---- Lower switch centered ("transient")
---- Attack to 1, Sustain to 0.002, Release to 1.5

Then it works as you are looking for - rise on attack for however long the key is down (I have an Easel-K so it might be a *little*
different) and then falls at the decay rate on key release.

And if you pull Sustain down to 1 or so,it's 'infinite sustain' till you push it back up away from you.

- Bill
musicalfungus
I can verify that my BEMI Easel Envelope works exactly like WSY has described when using my 218e to trigger the 208 envelope. Hopefully softroom can figure out whats going on with his Envelope.
musicalfungus
softroom

I watched your recent instagram videos and posted some comments on them. Hopefully you find my comments useful smile
wsy
I just did a double-crazy test and held down a single key (feather? whatever) on the Easel-K.... and sure enough, after maybe
10 seconds, the note started to fade, and in another 5 few seconds, faded.

So, it's "very long sustain", not "genuinely forever". Sorry for not getting it exactly right.

(and whether this is an artifact of the 223e not holding GATE forever or something else, I don't know; can the previous poster try
a sixty-second sustain and report back?)

- Bill
softroom
Cheers everyone for trying to clarify this for me. I'm old and maybe rather anal, but I do like to understand things, especially new and different things. (And this is about as different as it gets).

I found a way to make a simple organ-style envelope where the sustain time does seem to equate to the time a key is held. Within a small window around the .2 setting, if I have both sustain and decay at the same value it behaves as expected in Sustain mode.

I'm looking forward to tarandfeathers' document also as I'm tempted to let my techie loose on it. There's a fine line between quirky and wonky and I don't imagine Don would be pleased with the current incarnation. Of course, having the aux card, I have to wonder about the effects of tweaking on CV-controlled envelope times.

Thanks!
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