[linux-audio-dev] XAP status : incomplete draft

[David Olofson]

On Sunday 15 December 2002 18.31, Steve Harris wrote:
> On Sat, Dec 14, 2002 at 06:49:01PM +0100, David Olofson wrote:
> > I don't get it. If you're supposed to place the scale converter
> > *first*, then how are you supposed to be able to apply anything
> > like traditional music theory, rather than pure, continous pitch
> > based theory? You will have to know the *exact* temperament of
> > the scale (to decode the input, and to generate output in the
> > same scale), even if you're only worried about notes.
>
> That holds true for per-note descriptions too. The only way you can
> improve in it is with *extensive* scale metadata. Which we dont
> have and dont plan to have.

You're still missing the point. Note pitch is <something>/note, which 
is a linear scale. With 12t, it's identical to 12tET. This is very 
easy to process.

	np[0] = np_in;
	np[1] = np_in + 3.0/12.0;
	np[2] = np_in + 7.0/12.0;

gives you a chord. (I'm assuming we're using (1/12)/note, so the 
formats become equivalent is you assume ET scale or scaleless.)

Now, you can apply a scale converter with a pure 12t scale, and you 
*still* get the "same" chord, only sounding slightly different. (If 
you're close to the indended key, it'll sound better, otherwise 
worse.)


I don't see why this is so hard to grasp.


//David Olofson - Programmer, Composer, Open Source Advocate

.- The Return of Audiality! --------------------------------.
| Free/Open Source Audio Engine for use in Games or Studio. |
| RT and off-line synth. Scripting. Sample accurate timing. |
`---------------------------> http://olofson.net/audiality -'
   --- http://olofson.net --- http://www.reologica.se ---