[pianotech] Soundboard deflection - Pitch raise

[Ed Sutton]

This is an interesting thread.

I would point out that harpsichord and fortepiano pinblocks have a tendency to belly downward in response to the tension on the tuning pins. Old Bechstein pianos also have a characteristic break of the plate strut at the block that indicates a similar flexing. 

It should not be that difficult, with an appropriate gauge, to measure for downward deflection of the block after a pitch raise.

Ed Sutton
  ----- Original Message ----- 
  From: David Love 
  To: pianotech at ptg.org 
  Sent: Tuesday, August 04, 2009 8:24 PM
  Subject: Re: [pianotech] Soundboard deflection - Pitch raise


  Are you suggesting that soundboard deflection is the cause for the predictable 25% - 30% loss in the initial pitch correction even when that net change is similar whether pianos have no crown and no bearing or quite a bit of crown and ample bearing?

   

  David Love

  www.davidlovepianos.com

   

  From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of PAULREVENKOJONES at aol.com
  Sent: Tuesday, August 04, 2009 2:46 PM
  To: pianotech at ptg.org
  Subject: Re: [pianotech] Soundboard deflection - Pitch raise

   

  And unproved. David, where's the data?

   

  P

   

  In a message dated 8/4/2009 11:45:27 A.M. Central Daylight Time, AlliedPianoCraft at hotmail.com writes:

    Interesting.

     

    Al G

     

     

      From: David Love 

      Sent: Tuesday, August 04, 2009 10:05 AM

      To: pianotech at ptg.org 

      Subject: Re: [pianotech] Soundboard deflection - Pitch raise

       

      Not board deflection but plate contraction is the culprit.  

       

      David Love

      www.davidlovepianos.com

       

      From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Al Guecia/AlliedPianoCraft
      Sent: Tuesday, August 04, 2009 4:19 AM
      To: Pianotech List
      Subject: [pianotech] Soundboard deflection - Pitch raise

       

      I did 2 pitch raises yesterday (new customers). One was at A-418 and the other was A-420 before I started. What I found interesting was the amount of board deflection. On one of the pianos (A-418), the first 3 notes (A-0, A#-0 & B-0, were dead on, (go figure) on my first pass. I raised the pitch to 440, (some notes on this piano were 190 cents flat, wow!). On my second pass the first 3 notes were about 10 cents flat. I was surprised that the board deflected that much. No question here, just an observation I thought I'd pass on.

       

      Al G

       

       

   


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