Cracking the unisons

[Alan Barnard]

Ric said: "...One thing I learned at the Yamaha Technical Acadamy was to
listen to the lowest possible coincidents... and not really to just one
single pair."

I grew up with that, too: always tune to the lowest pitch, slowest beating
partial you can hear. and is absolutely correct for tuning fifths
(critically important) and other intervals ... but not octaves, obviously,
where we are aiming for a particular stretch (don't let the word confuse
you).

BUT it is also not the best idea for tuning unisons. For example, bass
unisons could be tuned to ensure no-beat at the octave and yet end up with
an ugly beat at the 12th unless the strings are perfectly matched (is that
possible). Even with badly mismatched bass strings, your best unison is
almost always found where the 12th (octave + fifth) is quietest. This is
handy, too, because it can be easily ghosted to isolate this partial when
there is a lot of junk in the strings when they are played directly.

Every user of Tunelab is aware of how often high treble strings have two or
more "peaks" on the spectrum analyzer--some are just a jumble of pitches in
the general neighborhood of the tuned pitch. So, for treble unisons, as
someone mentioned today, they must be tuned strictly by ear and strictly to
find the "sweetest" possible coincidence of partials even if the
fundamental is not exactly the same, especially when they are are noisy
strings--by which, I do not mean "wild" strings, that's a separate issue, I
just mean strings that do not produce one clear pitch. 

Alan Barnard
Salem, Missouri