summer sharpness in low tenor

[David Nereson]

    Yes, it has been observed often by many techs that the strings with the longer lengths from upper bearing point (pressure bar, capo, agraffe) to tuning pin go out of tune to a lesser degree than those with the shorter upper "waste end."  (or is it the other way around?)  
    Anyhow, I think that's only one factor.  Despite our best efforts to set the pin and equalize the various string segments, they're probably never 100% stable and equalized, and there's always that tension trying to make them go flat, so when case, board, and bridges expand or contract, the three strings of each unison (or two) don't necessarily move the exact same amounts.  And we know how little it takes to put a slight "meow" in a unison.
    --David Nereson, RPT
  ----- Original Message ----- 
  From: V T 
  To: pianotech at ptg.org 
  Sent: Wednesday, July 16, 2008 12:18 AM
  Subject: summer sharpness in low tenor




  Now that we covered the tenor and the low tenor, on to a more irritating stability problem: Unisons that go out with humidity.

  At first, one might wonder why three strings that are so close together on the bridge would follow independent pitch trajectories when the humidity changes. I did notice that, on my piano, the problem was most objectionable in the low and mid treble, but probably just as present all the way to the top.

  Speculatively speaking, I think it has to do with the fact that the total string lengths among the three strings are not really equal because of the tuning pin locations. Any thoughts about this?

  >Most pianos go quite sharp in the summer because of higher humidity, and
  >the sharpness is most pronounced in the low tenor.

  Vladan


        
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