[linux-audio-dev] more on XAP Virtual Voice ID system

Steve Harris S.W.Harris at ecs.soton.ac.uk
Tue Jan 7 09:15:00 UTC 2003


On Tue, Jan 07, 2003 at 01:49:23 +0100, David Olofson wrote:
> > > The issue here is this: Where does control data go when there is
> > > no voice assigned to the VVID?
> >
> > They get thrown away.
> 
> Right - so you can't play a polyphonic synth with a continous 
> velocity controller, unless you track and re-send the controls that 
> the synth happens to treat as note parameters.

I dont understand why.
 
> > Well, I thinik its OK, because the note will not be used to render
> > any samples until after all the events have been processed.
> 
> But who guarantees that whatever the "trigger" event is, also comes 
> with events for the "parameter" controls? It's trivial (but still has 
> to be done!) with explicit NOTE_ON events when assuming that NOTE_ON 
> means "allocate and start voice NOW", but it's not at all possible if 
> the synth triggers on voice control changes.

I dont think that matters, eg. my favourite exmaple, the gong synth. If
you issue a voice on it will initialise the gong graph in its stabel
state, and when you sned a velocity signal (or whatever) it will simulate
a beater striking it.

> > > If you really want to your voice allocator to be able to turn
> > > down requests based on "parameters"
> >
> > I think this would be complex.
> 
> Not more complex than any "note-on latched" controls - and I don't 
> think it's realistic to eliminate those.

There is a difference between "turning down" (implies communicating) and
ignoring (silent).

- Steve



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