A 435 or A 440 ?

[Stéphane Collin]

Hello Jack.

I put the formulas into a spreadsheet, and here is what I got.

I analysed the scaling of a piano whose A4 strings are 357 mm long and 0,850 mm diameter.  More than the right half of the scaling is pure pythagorean with an octave length ratio of 2.

Suppose you use Röslau wire, here are some numbers :

   tension in one string      at 440 Hz :  44.8 Kg          at 435 Hz :  43.8 Kg
   total tension on the frame             11.141 Kg                         10.889 Kg
   % of breaking strain                            33 %                               32 %

Suppose you use Pure Sound wire

   tension in one string      at 440 Hz :  45.1 Kg          at 435 Hz :  44.1 Kg
   total tension on the frame             11.212 Kg                         10.958 Kg
   % of breaking strain                            40 %                               39 %

So indeed, tension variations on the frame are not a concern, methink.
Now, the higher you tune one same string, the less inharmonicity you can expect, but also less sustain.  While difficult to realize on one single string, I believe that when playing the piano in its whole you certainly notice the difference, both in sound feel and touch feel.

Best regards.

Stéphane Collin.


  ----- Original Message ----- 
  From: Jack Houweling 
  To: pianotech 
  Sent: Wednesday, July 26, 2006 7:01 AM
  Subject: A 435 or A 440 ?


  Hello

  I am working on a Mason and Risch grand piano and the plate has a stamp that says  " International Pitch A 435" .

  Is it best to tune this piano to A 435 ?

  The mother tells me the daughter has perfect pitch. She is away at school so I cannot talk to her.  Would someone with perfect pitch be bothered by anything other than A 440? 

  Jack Houweling
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