Cracking the unisons

[Ric Brekne]

/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)./

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I'm not quite sure you understood what I wrote there Alan. I didnt say 
listen for thee absolute lowest unison pairs..... I said a more or less 
congomerate of the lowest partials more specifically the fundemental, 
2nd and 3rd.  And its only for tuning unisons that I made the reference. 
Low tenor and bass octaves are tuned using 4:2 and 6:3 tests at the 
acadamy.. and they place heavy weight on the 4:2 even for long pianos.

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/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./

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I must respectfully disagree. The 3rd partial match in unisons is far 
from always satisfactory.  Para-inharmonicity as some call it simply 
does not allow for any such generalization to work. NIMBA. This is one 
of my beefs with earblind use of ETD's... tho that moves into a 
discussion about octaves again.  But for unisons... the best result is 
when the oveall sound of the unison is a steady as possible. No single 
partial alone can define that criteria

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/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.

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The sometimes undefined treble fundemental pitch is a whole different 
issue of course.

Cheers
RicB
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/Alan Barnard
Salem, Missouri/



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