Hi Roger. I have tried what you describe below several times now on several different piano makes. Quality ranges from relatively new Steinway C's to the Tzech "P" piano. I still get the same in every instance. No matter how much I go back and forth re-adjusting string pitch to take care of any slight error I find that the results are basically not predictable. There is pitch drop on some coupled situations, rise on others, and no call on the rest. I also notice that once in a while you can even notice that the pitch can rise slightly as the amplitude of the strings vibration decreases. This is pretty seldom, but I cannot conclude anything else and that one has me really scratching my head. I think Ron is on the right track in looking at the soundboard / bridge as a possible cause. Roger Jolly wrote: > > Hi Ron, > Checking the coupling effect in the same manner as you > described, I had similar results. > However, If you tune each string separately for full blush on RCT. and redo > them a second or third time so that each string gives a perfectly stable > reading, them measure the unison it's very consistent 0.2 to 0.4 cent pitch > drop in the killer octave range. > I did this test in front of another tech on the list that has observed the > same consistent results. > A while back I posted some observations in tuning a full octave in the 5/6 > range. These test were done on newly strung pianos and well maintained > concert grands. > I would be interested in your observations using the same measurement > technique. > Regards Roger > Roger Jolly > Saskatoon, Canada. > 306-665-0213 > Fax 652-0505 -- Richard Brekne Associate PTG, N.P.T.F. Bergen, Norway
This PTG archive page provided courtesy of Moy Piano Service, LLC