[linux-audio-dev] Catching up with XAP

[Frank van de Pol]

On Wed, Jan 15, 2003 at 11:29:20PM +0100, David Olofson wrote:
> 
> Because that's just the way it is, even if you can "stretch" the 
> concept slightly. Ever implemented a MIDI synth?

In fact I did :-)

<snip>
> 
> > If you doubt, feel free to come over to my studio and hear my AKAI
> > sampler play multiple times the same sample at the same pitch :-)
> 
> I have hardware that does that as well, but it doesn't demonstrate 
> anything more than possibly a minor hole in the MIDI specification 
> AFAIK, there is no official statement as to whether synths should do 
> this or not, and either way, you'll find synths doing it in several 
> different ways. "Restart" and "new voice" are just two possibilities. 
> (I've mentioned other alternatives previously.)
> 
> Anyway, yes, many synths and samplers allocate new voices when you 
> send multiple NoteOns for the same pitch, but:
> 
> 	1. For many sounds, this is simply *incorrect behavior*.
> 	   Examples would be many percussion instruments, most
> 	   string instruments with fixed per-string tuning,
> 	   most pipe, tube, electromechanical and other organs,...
> 
> 	2. What happens when you send Poly Pressure...? One of two
> 	   things: a) the synth screws up and applies the effect
> 	   on a "random" voice, or b) the synth applies the effect
> 	   on all voicen playing on that pitch. 
> 
> 	3. What happens when you send NoteOff? Well, I have yet
> 	   to see a synth that even tries to match NoteOns and
> 	   NoteOffs - and it would be rather random anyway. What
> 	   happens is that the synth stops *all* notes playing
> 	   that pitch on the channel.
> 
> 	4. If we were to use separate events for VOICE_ON and
> 	   VOICE_OFF, nothing would prevent XAP synths from doing
> 	   the same thing. (However useless it is, when pitch is
> 	   separated from VVID.)
> 

I agree with you David.


> 
> > I see the use of the VVIDs but for some reason I get an
> > uncomfortable feeling seeing it; it just reminds me of over
> > engineering and adding unneeded complexity.
> 
> So, how do you propose we deal with voice/note addressing? Take the 
> MIDI approach, and forget about continous pitch...?
> 
> 
> > I'm quite glad my MIDI
> > devices are smart enough to do their voice allocation....
> 
> And XAP plugins would be no different in any way. VVIDs are just a 
> more powerful, but not really fundamentally different addressing 
> method.
> 
> This is not about voice allocation, but about voice *addressing*. 
> I've stated many times before that I specifically *do not* want 
> senders to have anything to do with the details of voice allocation.
> 
> 
> > Sorry, couldn't resist it.
> > Frank.
> 
> Sorry, but I still claim that MIDI note pitch is equivalent to VVIDs 
> when it comes to voice management. VVIDs are just more powerful. :-)
> 

In MIDI all of this is typically worked around by using multiple channels
using the same sounds. I understand your point and must admit that the VVIDs
are indeed very powerful. 

Frank.


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| Frank van de Pol                  -o)    A-L-S-A
| FvdPol at home.nl                    /\\  Sounds good!
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