re: micro-guitar-MIDI

[Bill Sethares]
> I figure that a 19-tet is a good place to start,
> at least partly because Ive played in it quite a
> bit (using a MIDI guitar controller).
>
I have a question about the MIDI controller. . .
Did you: *A* -- use a custom controller that sent a unique number for every
note (to a 19-tet synth)? or *B* -- was it a standard controller that sent
12-note-per-octave numbers followed by a pitch-bend message to cause a 12-tet
synth to mimic 19-tet?

I am curious because I too have a 19-tet guitar. I have hesitated to go MIDI
with it because I was worried that option *B* would glitch the attacks of
notes, and that option *A* would be expensive. Please tell of your experience
with MIDI on your guitar controller.

> But I also want a JI-style fingerboard, and am having
> trouble visualizing what to do.
> Theres the Catler guitar - which looks great -
> but is highly complicated, and I think Id prefer something
> a lot simpler.
>
Concerning fret placing. . .
String tension increases when you fret a note. This can make some notes sound
quite a bit sharper than you intended when designing your neck. The worst
affected notes are those *very* near the nut, and those beyond the octave fret
where the action gets high.

Before I had my 19-tet five-string bass made, I took a DAT to the luthiers shop
and recorded all 24 notes of the A-string (the middle string) of a bass he had
already made. This bass was fretted to 12th root of two. Back home I
transferred the recording to my digital audio workstation then used it to find
the exact frequency of the 24 notes. I then calculated the error between the
expected frequency (given the fret placing) and the actual frequency (due to
increased string tension).

I first worked out a fret placement for my bass using 19th root of two, then
applied alterations to each fret position to reduce the error found in my
experiment. Obviously I had to interpolate my 24 fret findings to determine 38
fret alterations.

THE POINT IS: If a JI-style fingerboard is to be accurate in order to minimise
beating intervals, I believe consideration should be given to compensating for
string tension when determining fret placement. Maybe I was too fussy with my
38 fret bass, it is after all a set of compromised notes anyway... so a bit of
string tension error on top of that is probably no big deal. *However*, I
wouldn't like the perfection of JI to be spoilt by it.

DARREN McDOUGALL