On Sunday 10 June 2007 15:55:45 D. Michael McIntyre wrote:
> On Saturday 09 June 2007, you wrote:
> > So the piece should sound the same, simply look different?
>
> Right. More broadly, we really need an easy way to flip around between
> written transpositions....
> That looks like just the sort of "you break it, you bought it" thing I was
> talking about. :) This stuff is really tricky to get right. It seems so
> simple on the surface, but it's so easy to miss the edge cases, and so hard
> to get them working without breaking something in the middle.
Hear, hear!
And the reason it's hard to get right is also wrapped up in the coding ideal
of Rosegarden: that it shouldn't get in the way of doing MIDI I/O easily. We
were (I hope) very careful to follow this lead, which is a good one, with our
microtonal and pitch-tracker patches. But when it comes down to it, MIDI is a
highly inadequate representation of musical information (as already noted, it
can't even distinguish enharmonic equivalents, for example!)
There are several other way of storing pitch, such as Base-40 or Binomial
representations (pitch class/spelling), but we think the only real way to do
it is to use a circle-of-fifths representation. We're working on one which
should handle almost everything including 19-ET etc microtonality. It's only
assumption is that all music is diatonic. And it makes transposition really
easy.
But then you'd have to be explicit about how you get from the note's pitch to
its frequency. MIDI completely ignores this step. Musicians call
it "temperament", and the results of just shoe-horn-ing everything into 12-ET
are shocking (there's a good little applet to show you just how out of tune
we all are here:
http://www.j2b.co.uk/tuning
:) ) Only keyboard players use anything like ET. Everyone else bends
everything. There's the MIDI tuning standard, but not very many applications
support that.
But do you want all this stuff in a sequencer? I doubt it, at least not as a
high priority. The pitchtracker supports temperament through the use of
tuning files. It depends where you chose to draw the line, I guess.
Nick/.
http://www.n-ism.org
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