[CAUT] How long to stabilize??

[Richard Brekne]

Good point Fred, if just a bit off in a tangent direction. But since you 
point their I'll add that your <<unison smear>> is a sign of excellent 
tuning technique. Far from all tuners get this result and IME  
(admittedly hardly a statistical compilation of valid samples) tuners 
who experience random movement of unisons as they go out of tune are 
coincident with tuners who's tunings are not stable in general. Which, 
by reverse reasoning gives any new tuner a measuring stick by which to 
examine their development by. If you start seeing unisons going out over 
time in pattern like behavior... then you are doing something right.

Cheers
RicB


    Hi Diane,
    There are a few patterns to pitch change due to humidity. The most
    noticed is at the tenor break, and also the treble break. But
    unisons go out in a pattern, also, on most pianos, usually more in
    the octave 5 and above range than elsewhere. This happens on
    Steinway Ds (I  always notice after a rain, or sharp fast change in
    humidity, and call it unison smear - a cent or so overnight
    sometimes), but is especially noticeable in many Yamaha and Kawai
    models (not to single them out, also other Asian makes), where that
    treble section might stay closer to pitch as a whole, but with wide
    skewing of the left and right strings. Often one will be sharp of
    pitch while the other will be low,  and the middle between. Also
    common is left or right on pitch, and the other below or above by
    quite a lot. Sometimes it is a 15 cent or mored difference. Ouch!
    Nasty unisons mean unhappy customer. (Talking here about after a 20%
    or more RH change, over a period of weeks).   I don't have an
    explanation, just observe it.
    Regards,
    Fred Sturm
    University of New Mexico
    fssturm at unm.edu