41-TET and those difficult synths

While I certainly agree with Brian that synthesizers are too
difficult to tune -- this is why the neglected MIDI Tuning Spec was
devised -- his test case of realizing a 41-TET piano sonata on a
synth with just one tuning table (even a 12/octave table) is perhaps
simpler than he suggests. Lest someone be discouraged from
exploring 41-TET, I offer a simple-minded solution that requires 4 MIDI
channels, no channel-clogging messages, and a single tuning table
(even a 12/octave table will do). It can be generalized to any ET.

Tune the table to the following degrees of the 41-TET scale: 1, 5, 9,
13, 17, 21, 25, 29, 33, 37, 41 -- that is, every fourth degree, for
an equal note spacing of 117.06 cents. Set the synth's global
pitch-bend range to one semitone. Send MIDI channel 2 an initial
pitch bend equal to 29.26 cents; bend channel 3 by 58.53 cents; and
bend channel 4 by 87.80 cents. You now have degrees 1, 5, 9... playable
on channel 1, degrees 2, 6, 10... on channel 2, degrees 3, 7, 11... on
channel 3 and so forth.

You still have to assign notes to the proper channel, which may be
a non-trivial task depending on the composition, but at least you can
get the pitches without inserting a lot of messages -- just one
pitch bend at the start of each track.

This doesn't invalidate Brian's point. The technique works
only with ETs, and it eats up n MIDI channels per timbre (where
n�grees/12). So if you're trying to realize an octet in Partch-43,
you would run up against the very real problems Brian describes.
Still, I thought I should pass the tehcnique on, simple as it is,
in case it wasn't obvious to some readers of the list.

(It occurs to me that some just scales. e.g. tetrachordal types, might
have internal congruences and repetitions that could exploit such fixed
channel offsets. These would, though, require tedious calculation on a
case-by-case basis. It would be an interesting exercise to determine
if the Partch scale is sufficiently self-similar to use this technique.)

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