The Logic Off Topic list

Thoughts from the mind of litepipe, 23-04-2001:

>   After twiddling with this all day I think I can finally explain what I'm
>trying to do. Presets on my keyboard are made up of two samples (pri.
>instrument and sec. instrument). So say I have an organ sound called
>Procol's Harem, when I look in the preset info the pri. instrument may be
>hard perc. organ and the sec. instrument may be soft pipe organ (just an
>example). This is what I want to change. With SYSEX I'm trying to make it
>possible to alter the pri. and sec. samples on the fly in Logic to create
>new sounds.

Sounds (again) like the M1, where a Program can be either 'Single' or 
'Double' -- i.e. use one or two 'sound sources' (oscillator, filter, 
amp).

>   So I came to the conclusion (I wouldn't really call it that, more like a
>guess) that what I should be doing is altering that particular program. What
>I mean is that If I have Procol's Harem on channel 4, I shouldn't access
>channel 4 I should acces the Procol's Harem program (preset), right? Because
>all I'm doing with channel 4 is accessing the Procol's Harem program, right?

That's indeed what you want.  The question is: is it possible?  To me 
it sounds as if the answer might be 'no'. I hope you'll excuse my (by 
now probably boring) comparison with the M1, but there still seems to 
be a lot of similarity.

On the M1 you have Programs and Combis.  A Combi is a multi-timbral 
setup of up to 8 Programs.  When you're in Combi-mode you can change 
which Program plays in any of the 8 multi-timbral slots, and you can 
change the channel on which those 8 Programs play (so they could all 
play on channel 1, or play on channels 2-9, or whatever).  However, 
while in Combi mode, you can _not_ change parameters of a Program 
itself.
If I use an organ Program in a multi-timbral setup (i.e. a Combi), I 
cannot change it's 'base sample' from Organ to AcouPiano for example. 
For this kind of edit, I have to be in Program mode (i.e. 
non-multitimbral).
So if I do want to make this sort of on-the-fly changes, I need to 
have 2 different Programs, one based on Organ (e.g. Program number 
21) and one based on AcouPiano (number 22), and then in Combi mode I 
can change the multitimbral "slot-assignment", so that "slot 4, 
playing on channel 12" is assigned to Program 22 instead of 21.

>   I'm trying to think of it as creating a new instrument where not only can
>you choose which channel and program you want to play, but also tweak
>individual parameters for that specific program.

This depends on the structure of the Emu.  Can you, using the Emu's 
front panel, do the things you describe (i.e. edit the multitimbral 
setup _and_ edit parameters for the constituting programs at the same 
time)?  If not, than you can probably not do them by sysex either. 
As I explained above, the M1 can't do this -- I have to switch from 
Combi mode to Prog mode on the front panel in order to access either 
the Programs _or_ the multi-timbral Combis.

If I insisted on doing something like this on the M1, each sysex 
fader should have the following chain of events associated with it:
1) switch to Program mode, 2) send Program change to access the right 
Program, 3) change parameter, 4) send Program Write Request, 5) 
switch back to Combi mode.  That means that each fader movement would 
generate 4 sysex messages plus a program change -- not a very elegant 
or workable solution.  And it probably wouldn't even work: if you 
drag a slider up quite fast, you would soon be generating tons of 
sysex, having the synth flip back & forth between various modes -- 
which the synth might find hard (or impossible) to digest.  Or you 
get a midibuffer overflow on the Mac.  Or any of a bunch of similar 
problems might pop up.

>Am I way out on Mars here? Is this even remotely possible? It's almost
>perfect now except that I want the SYSEX message I'm sending to be specific
>to a choosen program (preset). And to be able to do this with several
>programs that are on different channels at the same time.

Well, editing the multi-timbral parameters for individual programs 
should be possible (stuff like relative volume, midi channel, maybe 
"keyzone", etc) -- but that's obviously not the same as editing 
program parameters (filter attack time, LFO waveshape, etc.).

Your best bet might be to edit the Emu's 'base patches' (Programs) 
while in non multitimbral mode, and then afterwards assemble them in 
a multitimbral setup (Combi).

>   Am I starting to drive everybody crazy with all this or what?

No, not at all.  Being a teacher I get routinely confronted with 
much, MUCH sillier questions than yours :-).


cheers,
HJ
-- 
     Hendrik Jan Veenstra    ( h@... )