[linux-audio-dev] Plugin APIs (again)

Nathaniel Virgo nathaniel.virgo at ntlworld.com
Sat Dec 7 19:29:01 UTC 2002


On Saturday 07 December 2002 11:29 pm, David Olofson wrote:
> [..]
>
> > MIDI has 2 velocities - note_on and note_off.  I see velocity as
> > specific to those two events.  Isn't a new velocity event really a
> > new strike or attack of the instrument, or, in other words a new
> > voice (even if it cancels the previous voice)?
>
> Nope. An a violin, you have no "velocity" event at all (unless you
> want to use it for the subtle sound of the bow impacting or leaving
> the strings), but rather a "bow speed" event - which is continous.
>
> > That said, I hate
> > that Velocity is special.  I could be convinced.  I could also
> > stand and argue.  Not sure I know which I prefer...
>
> Well, keep arguing, and I'll try to figure out more reasons why
> velocity is not special, nor universal. ;-)

I think velocity is special because it is often needed by the synthesis 
algorithm only at the beginning of the note.  For instance, if you have a 
physical model of a bell then the velocity will determine the shape and 
magnitude of the impulse function you use to represent the striker.  Changing 
it midway through the note, after the bell has been hit, is meaningless.

That said, it would be cool if you could support multiple velocity-like 
parameters, so that it would be possible to control the position of the 
striker and the strength of the strike independently for each note.  Multiple 
poly-aftertouch-like controllers would also be cool, but I think they are a 
different thing.




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