I'm definitely seeing the same behaviour Scott describes. I can't decide if
I see Elhardt's first problem or not. It seems like the voltage output is
"lifted" partially if there's insufficient release time.
This seems to be a problem only for short attacks, below about 2 or so
(25ms). The effects are less pronounced for non-zero attack and tend to go
away after about 2.
As for the second problem, it seems that there's the initial attack to
almost 5 volts, a short decay down to 4 volts, and then the actual decay to
whatever sustain level, whether its above or below the initial 4 volts, when
you have A=0. Again, this is only a problem for short attacks; the longer
the attack the less pronouced this initial droop is. With low sustains,
this "droop" also contributes to decay time, so if you set sustain=4 or 5
the minimum decay is about 25ms at A=0.
Elhardt, I suspect the "lack of attack" you hear is due to the second
problem. The envelope is "decaying up" briefly, even when you have D=0.
I tried both keyboard gates and the pulse output from a '320.
...Craig
----- Original Message -----
From: "Scott Juskiw" <scott@...>
To: <motm@yahoogroups.com>
Sent: Wednesday, May 08, 2002 10:08 PM
Subject: Re: [motm] Annoying MOTM envelope behavior
> At 2:35 AM -0400 2002/05/08, elhardt@... wrote:
> >Ever since I built my MOTM I haven't liked the way the envelopes worked,
yet
> >I've never heard anybody else comment on them. I'm wondering why not.
Is it
> >just me that experiences the following problems?
>
> I have four 800s and I tried to replicate the problems you are
> seeing. I patched the envelope into the FM input of a 300 so it was
> easier to hear the envelope. I tested using the Gate out from a
> Pro-One into the GATE input of the 800s. I didn't put anything into
> the TRIG input.
>
> >1) I patch up a sound and hit a key on the keyboard to trigger the sound
and
> >it sounds OK. Then I start playing and all of a sudden the sound gets
> >brighter and louder (I have envelopes going to both filter and amp).
This
> >isn't right. The envelope should not output higher voltages because I'm
> >playing faster or more legato, yet it does. I finally got around to
scoping
> >it and confirmed it. With the exception of a little initial spike the
ADSR
> >outputs about 4 volts max. Yet at certain settings if I play a fast
trill I
> >can push it up to about 6 volts. Set A=0, D=6, S=7, R=4 and go into the
a
> >filter FM input and you'll see what I mean.
>
> I used A=0, D=6, S=7, R=4 as you suggested but couldn't find anything
> bizarre; the envelopes behaved as I expected them to. However if I
> use A=0, D=10, S=10, R=10 and trill rapidly then I can get a
> sustained 6.4 volts out. I wasn't expecting that.
>
> >2) If the Sustain level is set way up to about 10, then the Decay acts
like
> >an Attack. I can set the Attack to 0 and move the Decay around to get
> >various length attacks. It seems to control the attack time from the
normal
> >4 volts up to a higher voltage which is set by the sustain level.
Strange.
>
> I get this one too. If I set A=0, D=10, S=10, R=0 then the envelope
> hits 4 volts almost instantly and then exponentially decays UP to 5
> volts over a period of around 15 seconds. If D=0 then the decay UP to
> 5 volts is almost instantaneous.
>
> >3) I can set Attack to 0, Decay to 0, and Sustain to 10 to get plain
organ
> >type envelope, yet the attack portion is too soft. It's impossible to
get a
> >hard solid sound at this setting.
>
> Hmmm, mine sound snappy enough to me. I usually don't even use A=0
> because I find it too snappy at that setting. Maybe there's some
> extra resistance in your Attack pot (it's not 0 ohms when fully CCW).
> If I set my Attacks to greater than 0 then my results are much closer
> to yours.
>
> >And I haven't even gotten into the somewhat artificial sound of the
envelopes
> >either because I need to compare side by side with another synth. But
they
> >almost sound linear instead of exponential (even though I'm sure they're
not)
> >and don't seem to have a really good bouncy and punchy quality I like.
But I
> >need to compare to others before I can say for sure what's going on here.
>
> They sound exponential to me. The only thing I miss is a really long
> attack time, 20 seconds would be nice. If I ever find some good 5 Meg
> log pots I might try replacing my Attack pots.
>
> >
> >I've never experienced these things with any of my other synths. Am I
the
> >only one dealing with these issues?
>
> I never noticed these 800 oddities until you mentioned it. I'm glad
> you brought it up, you're certainly not alone.
>
>
>
>
>
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