Envelope time units?

[jvonachen]

What are the time units of envelope parameters that are time based: Delay, Attack, Decay, Sustain, Release?
They show 0-127 but of what?

I have a Welsh's Synthesizer Cookbook and the recipes show envelope parameters in seconds.  I was wondering how to map that.

[jvonachen]

Sorry.  Not sustain, but the others.

[wbajzek]

I don't think they're uniform units of time. When I tried implementing patches from that book, I found that I just had to time it and not be too worried about absolute precision.

[jvonachen]

if that is the case that's too bad.  You gave me an idea.  I could make a MIDI item in Reaper and increase one of the parameters by one each time and then look at the recorded wave and determine how it's mapped.  It might be a log progression.  Too bad we can't get an engineer from Seq. to chime in on this.  Hello?

[wbajzek]

That could be. I've done some coding of digital synthesizers and have found that you probably want more precision in the short end of the range than in the long, and when you could be talking about instantaneous to many seconds of length, a linear response to the knob is not advantageous.

But anyway, I just remembered that this other thread exists which would help answer your question: https://forum.sequential.com/index.php/topic,3203.0.html

[jvonachen]

Thanks that did help.  These are numbers from Rev 2 amp attack numbers, are they the same for all time based envelope parameters?  Are they the same for Mopho?  Only analysis would tell us.

Amp Attack Envelope Curve
Here's some visual reference material regarding the timing and shape of amp attack on Rev2.  Data points taken every 8 values, from 0-127.   Measured attack times are approximates within a very small margin.

Amp Attack Value     ~Milliseconds
0   3 ms
7   10 ms
15   31 ms
23   75 ms
31   135 ms
39   195 ms
47   260 ms
55   390 ms
63   605 ms
71   735 ms
79   950 ms
87   1260 ms
95   1830 ms
103   3060 ms
111   6080 ms
119   14220 ms
127   24660 ms

[wbajzek]

They're most likely the same for the Mopho. I don't know about the other parameters, though.