Envelope Triggering

[noonie]

Hi all,

First off, I just want to what a great resource this place and the old board have been to me. I got my fusion about a year ago, but am really just finding the time now to really dig into it. I'm just getting back into playing after about a 10 year break....so as you know, I've got a hell of alot to learn.....especially since my only previous experience with programming was with a Crumar Stratus back in the late 80's. Thanks to everyone who has shared their knowledge on these boards.


On to my question....I'm trying to create a sound similar to the riff that can be heard in "Where Do I Begin" by The Chemical Bros (at about 1:10 into the song and again near the end). The filter cutoff is modulated by a LFO the starts out very fast and decreases to just about nonexistent by the end of the 2 measure riff. (Well, I think that's what's going on anyway, heheh)

I'm trying to get it so the LFO envelope doesn't retrigger every time I hit a note. I know I can do this by setting the appropriate parameter and playing legato, and that's how I've been doing it. However, I'd really like to be able to do this without playing legato.

I've tried fiddling with every parameter I can think of in the envelope and the LFO it self, and every combination I could create and cannot seem to get this to work. I've even set the trigger on the envelope to one of the "T" buttons, but the envelope still stops whenever I strike a key, unless I'm playing legato.

IS there a way to do this, or am I just not completely understanding the parameters? I would think setting the envelope trigger to anything other than the keyboard should let me do this.

[gwenhwyfaer]

Having played around, I see what you mean... and I think I know what's causing it.

I think that the envelope generators are actually deallocated once a note has fallen into silence - and when they're reallocated they're triggered anew. (That's probably a bug, thinking about it, but not a desperate one.) Other than that, the retrigger works fine.

However, the other thing I tried works just fine - rather than an envelope, set the first LFO to the lowest rate you want, and then add another LFO to modulate the first LFO's rate between that and the highest you want; set this second LFO to a sawtooth wave at -100%, set its phase to be -100% also (so it starts from the top of its range!), and set its sync to "8 Whole Notes" (which will give you your 2 measures). I set its Retrigger to T1 Down myself, but None works just as well. That should give you what you want...

Let us know how you get on.

[markone]

gwenhwyfaer said:

Having played around, I see what you mean... and I think I know what's causing it.

I think that the envelope generators are actually deallocated once a note has fallen into silence - and when they're reallocated they're triggered anew. (That's probably a bug, thinking about it, but not a desperate one.) Other than that, the re trigger works fine.

However, the other thing I tried works just fine - rather than an envelope, set the first LFO to the lowest rate you want, and then add another LFO to modulate the first LFO's rate between that and the highest you want; set this second LFO to a sawtooth wave at -100%, set its phase to be -100% also (so it starts from the top of its range!), and set its sync to "8 Whole Notes" (which will give you your 2 measures). I set its Retrigger to T1 Down myself, but None works just as well. That should give you what you want...

Let us know how you get on.

I'm not so sure that is a bug.

I've used the legato envelope trigger to emulate the percussion behaviour of a Hammond B/B3 where the envelope always retriggers on single notes or during staccato play, but never retriggers while you are playing legato. This is exactly the right behaviour, from my POV. But I guess triggering LFOs is a different thingie altogether.

[gwenhwyfaer]

No, that's a different thing from what I mean - that's just the Legato setting of the envelopes; I'm talking about much less predictable envelope behaviour...

On the other hand, I'm not sure my diagnosis was correct. There's definitely something odd going on with envelopes, but it only seems to be going on in Monophonic mode, where sometimes envelopes don't retrigger when they're supposed to when you play staccato (and apparently randomly, unless you leave long enough between notes - which suggests that envelopes are sometimes continuing with their cycles rather than retriggering as they should). In Poly mode, everything seems to work nice and predictably - BUT the Fusion appears to deallocate all a voice's envelopes when the voice falls into silence.

(However, I might be wrong about that; if I am, the Freerun parameter will work after all. I'll go test that now.)

*goes back and fiddles*

...OK. I'm not wrong.

In Poly mode, all the envelopes work predictably - but they are always retriggered on staccato playing, although they can be made not to retrigger on legato playing. So setting an envelope to Freerun with a trigger of T1 and legato on will leave it waiting for the trigger on every staccato note, but will maintain the envelope on legato playing - and setting the trigger to Key Down essentially makes Freerun mode go away. That's what you'd expect in Normal mode, but what I'd expect for Freerun mode is that it always finished out its Attack, Decay and Release, and only responded to triggers when it had run through that cycle. So yes, I'd say that was a bug with the Freerun implementation, but not a big one - it could just as easily have been a deliberate choice on Alesis' part.

(Also it turns out that if you set a trigger for the LFOs, they are also reset every note - so the only way to achieve the effect noonie is after in Poly mode is to set the second LFO's trigger to None. Then it freeruns.)

However, in Mono mode, something very odd is going on. With the same set up, what I found was that when I played a note, and then pressed T1, the note would go "wobbly" (as the envelope was triggered and the LFO rate changed), but then would go wobbly on every subsequent note as though the trigger had suddenly changed itself to Key Down. Leaving the envelope for long enough to finish what it was doing restored former behaviour. (Likewise, whilst I was playing I found that the filter envelope wouldn't retrigger if I played staccato notes too quickly.) So something fishy is going on there... I just don't have a handle on quite what, yet.

(Note that this doesn't mean you can't set voices to monophonic - setting them to Poly but setting the voice allocation to 1 works very nicely. You do lose the ability to play a trill by holding one note down and repeatedly hitting another, but depending on the voice I can live with that.)

I'll report to Alesis when I have some test patches to send them, and when I can tell them a little bit more than "there's some weird shit going on here" but these are tiny, obscure bugs that only voice creators will trip over, so I can't see them being a high priority.

And let's not forget that one of the best-loved synths of all time is so revered because of a huge great bug in its filter implementation

[noonie]

Wow.... Thanks Gwen, I'll give the 2 LFO thing a shot whne I get home tonight. It actually makes more sense to go that route just based on the fact that I can synch the 2nd LFO to 2 measures, and not worry about endlessly tweaking the envelope times till there were just right. Why didn't I think of that?


Regarding envelope freerun..... during my struggle with this, I think it seemed that the envelope would actually "run free" if you hit the same note, playing either staccato or legato. It seemed to retrigger after changing notes. I remember thinking that, ok, maybe the freerun mode is per individual note/voice.

It's been a little while since I was fiddling with this, so I may be remembering incorrectly. But I'm glad I was at least semi-correct in my undestanding of what "should" be happening. I realize that ultimately it's a matter of Alesis's implementation intentions.....I wasn't sure if the problem was simply my ignorance.

BTW Gwen, I sure did miss your contributions back in the old forums...glad to see you here!

[mps]

It is great to have Gwen here.

[noonie]

I redid the sound using the 2 LFO route and it worked like a charm.

Thx again!

I hope to fiddle around a bit more with the envelopes to see if I can perhaps cite a few more specific instances of this behavior and try to isolate the cause.