---------------------- multipart/alternative attachment Single string terminations with a loop at the hitch pin which show=20 instability most often can be corrected by pushing the loop coil toward=20= the hitch pin with a dull screwdriver impacting the screwdriver with=20 the heel of the hand. This helps to close the loop around the hitch pin. Also, leaving the string at pitch on the decreasing of tension leaves=20 the string terminus to tuning pin at a lower tension than the speaking=20= length which upon subsequent equalizing during playing will cause the=20 pitch to go flat. If the friction at the agraff/capo is very high,=20 equal tension in the string segments may be sufficient; if the friction=20= is low, the agraff to tuning pin segment may have to be left at a=20 higher tension. Daniel Gurnee, RPT, HSU retired. On Saturday, May 21, 2005, at 05:21 PM, Cy Shuster wrote: > I'm seeing some strange pitch drops in individual strings, and I can't=20= > figure out why. > =A0 > First, the history. > =A0 > This is a 1974 Yamaha C3, in pretty good shape, in the large band room=20= > of a community college, with central HVAC.=A0 No D-C on the piano.=A0=20= > Three weeks ago, we moved it overnight to two different off-campus=20 > locations for the spring concert series (half an hour ride in a pickup=20= > truck each time -- yikes!=A0 I covered it up, but still...).=A0 It's = had=20 > five tunings in the last month, and I've recorded humidity each time.=A0= =20 > I use TuneLab Pro, and used the same stored tuning each time. > =A0 > The series ended May 1, and I tuned it just before that concert.=A0 It=20= > survived the concert sounding good; no slipped unisons.=A0 It's been = in=20 > the same spot for three weeks, uncovered, lid down. > =A0 > Now, the mystery. > =A0 > On Tuesday, they asked me to tune for a recording the next day,=20 > mentioning that a few unisons were out in the top two octaves.=A0 I=20 > measured all the A's before I tuned (as is my habit).=A0 A4 and below=20= > were right on, except A1 and A2 were up about two cents (humidity is=20= > rising).=A0 A5 was up 3c, A6 down 6, A7 down 3.=A0 I noticed that in = many=20 > treble unisons, one or two strings would be way off: either a string=20= > would be right on, or off by a considerable amount (is it my=20 > string-settling technique?).=A0 I also noticed that many strings would=20= > move a lot if I pounded on them, before touching the pin.=A0 I worked=20= > hard on those top two sections of the plate, making sure every string=20= > was well settled, and wouldn't move. > =A0 > Yesterday, they called me back to tune their other piano, and also=20 > mentioned that the top two octaves were out on the Yamaha again (!).=A0=20= > I checked it, and A2 and below were spot-on, as were A6 and above.=A0=20= > But in the middle three octaves, a dozen notes had one, two, or three=20= > strings off by two or three cents (A4 was down five cents!).=A0 All = but=20 > one were flat.=A0 Again, either a string would be exactly in tune, or=20= > off by a lot.=A0 I checked the pitch of every string before I began to=20= > tune, and chalk-marked the tuning pin of each string that was out (for=20= > next time).=A0 > =A0 > They did mention that they turned off the A/C in the room for the=20 > recording (because of noise), and then fired it up full blast during=20= > breaks. > =A0 > Here's the temp/humidity record (graph attached).=A0 Humidity was = lower=20 > in the two off-campus locations, and has climbed steadily upwards. > =A0 > 4/10: 72F, 42% > 4/17:=A068F, 32% (off-campus) > 5/1:=A0=A0=A068F, 39-41% (back home; last concert) > 5/17:=A072F, 44-48%RH. > 5/20:=A072F, 55% > =A0 > By the way, the other piano didn't exhibit this symptom of individual=20= > strings falling, and others staying right on.=A0 This is really the=20 > heart of the mystery to me.=A0 My experience with pitch swings from=20 > humidity is that it affects strings evenly.=A0=A0The other piano is=A0a = D in=20 > a different room, with similar humidity, also last tuned 5/1.=A0 It = was=20 > sharp a few cents evenly across the middle, dropping down to -10 in=20 > the top octave.=A0 > =A0 > Maybe it is my tuning=A0lever technique?=A0 I usually finish a string = by=20 > coming down to pitch, to make sure the pin has no residual torque;=20 > maybe I'm leaving some tension in the front string segment that=20 > settles back to the speaking length during play, or humidity changes?=A0= =20 > In writing this history, I notice that the top two sections that I=20 > worked hard on Tuesday night were still fine; the problems I found=20 > yesterday were lower down. > =A0 > The other possible suspect is loose bridge pins.=A0 Earlier I had=20 > noticed a consistent drop around A6 on some strings, and found I could=20= > slightly move a few leading bridge pins with screwdriver pressure.=A0=20= > How this would lead to pitch drop, I'm not exactly sure... > =A0 > --Cy Shuster-- > Bluefield, WV > =A0 > <humidityHistory.JPG>_______________________________________________ > caut list info: https://www.moypiano.com/resources/#archives ---------------------- multipart/alternative attachment A non-text attachment was scrubbed... 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