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SEQUENTIAL/DSI => Prophet => Prophet Rev2 => Topic started by: jrajav on June 06, 2021, 03:31:38 PM

Title: Env3 / Auxiliary envelope repeat - how does sustain work? Clock sync available?
Post by: jrajav on June 06, 2021, 03:31:38 PM
Hi! Very new and happy owner of a Prophet rev2 here, deep in reading the manual and getting familiar with its parameters for the first time. Most things are pretty obvious even if they're a little opaque sometimes but one thing in particular is stumping me, and it's really difficult to search for an answer due to the nature of it (I did do a search through this forum a few different ways first):

That is how envelope 3 / the auxiliary envelope decides what the sustain length or overall envelope length should be. With a key-triggered envelope of course the sustain is infinite, but when Env3 Repeat is turned on, there still seems to be some set length of sustain - it doesn't simply jump straight to the release. When the sustain is turned up and down, it seems to increase the sustain time and not just the sustain amplitude. That is, higher sustain values result in more time spent in sustain. But the range is limited, the highest value of sustain still results in a relatively short time. It also doesn't seem to be clock synced - changing the tempo doesn't affect time spent in sustain.

So my questions are first, what determines that sustain time and what is its range? Second, is there any way to change sustain time or is that just locked in to the sustain level? And lastly, is there a way to clock sync the sustain (or probably better yet, the entire env3 repeat envelope length)?
Title: Re: Env3 / Auxiliary envelope repeat - how does sustain work? Clock sync available?
Post by: jrajav on June 07, 2021, 08:07:36 PM
I believe I found the answer for myself. I searched through the manual again and found this section that I'd missed:

Quote
Env 3 Repeat: Off, On—When on, the Delay, Attack, and Decay
segments of the envelope repeat. Sustain still affects the level at which
the Decay segment ends, but instead of sustaining at a fixed level while
a note is gated on, Delay, Attack, and Decay loop until the note is turned
off. The Release segment begins when the note is gated off, just as it
does when Repeat is off.

So after reading that I said "Aha! There is no sustain phase!" and went back to confirm - set up a really obvious attack / decay onto cutoff, played with the sustain, and..... still a clear difference in total envelope time. What the heck?

So I ran an experiment, armed with new knowledge. It seems that there is no sustain phase, but the envelope length does still vary based on sustain level. This is because the decay slope and time does not change, but the decay is considered "complete" and the envelopes resets and repeats once it reaches the sustain level. At least, I'm pretty sure that's what's going on.

See the attached image for a visual of the experiment I ran - notice that there are only ~9 envelope cycles for the low sustain settings, just over ~10 at 93 sustain, and it shoots up to ~15 at 127 sustain (where there is none or almost no decay at all).

(https://i.imgur.com/7kVOKxS.png)
Title: Re: Env3 / Auxiliary envelope repeat - how does sustain work? Clock sync available?
Post by: jrajav on June 07, 2021, 08:09:21 PM
I'm still interested in knowing if there is a way to clock-sync the envelope repeats, by the way! That would open up a ton of creative possibilities for the aux envelope and this still doesn't make it clear how that could be accomplished - it seems that it's probably just not possible though.