[CAUT] Detuning phenomenon; was: How long to stabilize??

[Jeff Tanner]

At USC, it was most noticeable on Baldwins.  The pianos would remain right at pitch but the unisons would go out in no time in this same pattern.  Since the Baldwins have Accu-Just hitch pins that aren't spaced in any predictable pattern that would support it, I sort of reasoned that threw the whole string length explanation out the window and made the phenomenon completely unexplainable.

Besides, what doesn't make sense is that one side pulls sharp while the other goes flat.  It would seem to be more reasonable that the change in pitch would be varying degrees of deviation in the same direction.
Jeff Tanner
  ----- Original Message ----- 
  From: Andrew Anderson 
  To: College and University Technicians 
  Sent: Thursday, February 19, 2009 11:12 AM
  Subject: Re: [CAUT] How long to stabilize??


  Speaking from an observational point of view without carefully measuring; it seems that the opposite swing of the outside unison strings might be related to unequal string lengths between tuning and hitch pins.  Seems to me that this is one of the stated reasons for single string unisons a-la Bosendorfer et al.  Having a little experience with Bosendorfer, I am not certain that this holds up under scrutiny, comparatively. The opposite would then be true of uprights as well and I do note the swing in them, some more then others.


  Maybe someone has already investigated this and can lay these questions to rest... ?


  Andrew Anderson  


  On Feb 19, 2009, at 9:43 AM, Ed Sutton wrote:


    In years past this has been much discussed on CAUT, and never clearly explained.

    Ed S.
      ----- Original Message -----
      From: Christopher Purdy
      To: caut at ptg.org
      Sent: Thursday, February 19, 2009 10:35 AM
      Subject: Re: [CAUT] How long to stabilize??


      I've seen this a lot but could never explain it.  I thought I was going nuts.  Glad to hear I'm not the only one in the nut house.


      Chris




      On Feb 19, 2009, at 10:24 AM, Fred Sturm wrote:


        Often one will be sharp of pitch while the other will be low, and the middle between.






      Christopher D. Purdy R.P.T.
      Registered Piano Technician
      School of Music, Ohio University
      Rm. 311, Robt. Glidden Hall
      Athens, OH  45701
      Office (740) 593-1656
      Cell    (740) 590-3842
      fax      (740) 593-1429
      http://www.ohiou.edu/music







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