impedance and empericism

[Ron Nossaman]

>Empiricists:
>
>Distractions abound. 
>
>The original question went something like "Don't we have to worry about all
>sorts of extraneous influences before we can discuss tuning optimization?"

I thought the last divergence was "Why can't the same inharmonicity curve
be used year round on a given piano?", or "You can't just measure all the
notes once and expect the result to be optimal on the next tuning", or
something to that effect, which got us off on soundboard impedance changes
with humidity  affecting inharmonicity, thus partial frequencies. This
ought to be easily enough tested and verified with the ETDs available. I
thought a few folks said they had done so. As far as a single tuning
program for a given piano being usable year round, I submit that some
people using ETDs already do it as a matter of course with pianos that get
tuned frequently enough to warrant a tuning file, and I doubt that the
difference in the result from season to season is noticeable aurally. Most
of the concerns being worried about here are concerns that didn't exist
before the ETDs became available and showed us a "problem" we couldn't hear
the week before. I seriously doubt that, at the measurement resolutions
easily available today, you could take measurements for each note in a
piano, end to end, then do it again immediately after finishing the first
pass, without having touched a tuning pin, and get identical results. I
submit that if that's the case, we're already past the resolution of the
available data. Curve fitting and various approaches of statistical
extrapolation can very possibly produce as near an optimal tuning program
as is worthwhile for a given piano, but the inconsistencies of the
attempted measurements would seem to indicate that the physical tuning of
the piano to the computed standards is just not possible. It's like spit
shining sandpaper. The media just ain't conducive to the process beyond a
point and you're probably going to be a little disappointed with the end
result. That's not to say that there isn't an easier or more efficient way
to sample data and generate an "optimal" tuning, or at least a tuning at an
acceptable level of "optimal" for the time and trouble spent. There's going
to be a lot of minor junk that just won't resolve in a real piano.

Take two readings, drink plenty of fluids, and call us in the morning. 

PS: I checked out the Veritune web page, and the idea of successive
refinement with each note tuned seems to make sense and kind of appeals to
me. The inharmonicity divergence isn't nearly as important on the second
note tuned, half an octave away from A, as it is at a break two octaves
away, or three octaves up scale. I'm intrigued.

Ron N