1/2 cent difference on unison

[Billbrpt@aol.com]

In a message dated 98-01-29 18:03:33 EST, you write:

<< No, I tune the first string as well as I can, and then I tune the other
 strings to the first.  The effect is not uniform, and I've decided that any
 attempt to compensate may actually result in greater error, if in fact
 there is error in the first place.   >>
Dear Jim,
What I do about this is to never create any interval, octave or otherwise
using a whole unison against a single string.  The last thing I do are my
middle unisons.  (Once again, different and the opposite of what most people
do).  Everything else in the piano is already done, treble and bass.  That
way, aurally or electronically, my octaves are always determined with single
strings.  If there is a general shift downwards, I figure that the whole thing
then shifts, like the doppler effect.
    I do think that sometimes there may be confusion between tuning stability
and this phenomenon.  Those who insist that using a strip mute will not
produce a fine tuning try to "raise the pitch and fine tune at the same time"
as George Defebaugh warned could not be done.  I've always remembered his
teaching and admonition and find that I can easily tune a piano faster twice
than I can fight with it once.
   Anytime you are changing the general pitch of any area of the piano, the
pitch of a unison will change as you progress through it and beyond it.
    The coupled motion phenomenon is very real, though.  By doing the test
that I mentioned, tuning a solid, clean sounding unison, so that it will at
least be aurally acceptible, stopping the ETD pattern, then checking the
single string, the single will always roll sharp.  Check the unison as a whole
again, it will stop the pattern.  I have not tried this on very high notes or
notes deep in the bass bichords.  It does seem to me though that I have
noticed this effect while tuning some of the higher bass notes.  I was not
experimenting, it was just an observation.

Bill Bremmer RPT
Madison, Wisconsin