Re: [microsound] pitch/harmonics, math and perhaps samples too?

[Dave Watson <dave@xxxxxxxxxxxxxxxx>]

On Oct 18, 2004, at 4:32 PM, Kassen wrote:

> By the way, Is anybody aware of a pitch shifting implementation that
> can
> work based on arbitrary tunings? preferably easy to use ones? I´ve
> done some
> very minor dabeling in tunings and would love to take it a little
> further
> but sample based methods of working generally don´t considder tuning
> while I
> think that for extreme time streching tuning becomes very signifficant
> indeed because beatings will become far more prominent. Since beating
> chords
> are at the treshold between the structure of tones and that of the
> composition I would count these as a part of microsound, yet a quick
> glance
> at the index of Roads´s book reveals no trace of this.

If whatever you're using to do pitch shifting allows you to set the
amount of pitch shifting to occur as a ratio this shouldn't be too
difficult.  Just use 3/2, 5/4, 9/8 etc. as the ratio.  If there is a
tune knob that lets you adjust the shifting in terms of cents that
would also work.  Zero cents is the tonic, 204 cents is 9/8, 386 cents
is 5/4, 702 cents would be 3/2.  The more consonant of the equal
tempered tones aren't off by very much, perfect fifth (702) cents is
just barely sharp.  The 5/3 A on the other hand (all of this is
assuming C as 1/1) is quite flat, being 16 cents flat.

I suspect most samplers don't give major consideration to letting you
choose an arbitrary tuning because they expect most to probably play
them from a 12tet keyboard.  As well, in some tunings the pitch of E in
the key of A  would be a different pitch (sharp with respect to 12tet)
than the E (flat w/ respect to 12tet) in the key of C.

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