Dipole Effects and Leaks in Soundboard; was Isolated Air-Movement

[Erwinspiano@aol.com]

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In a message dated 1/31/2004 4:35:49 PM Pacific Standard Time, 
tlesher@sachnoff.com writes:
As for the holes, although there's no substitute for somebody taking 
frequency spectrum measurements from a variety of positions and then plugging the 
holes up and doing it again, I think I can handle that question a little more 
satisfactorily than the other one.  I wish I still had the equipment to take some 
measurements myself, but various upheavals took their toll some years ago.  
But give me some data if you want and I'll see what I come up with. 

Best r egards,

Trent Lesher

(tuning student, amateur pianist)
      Trent
     Interesting post. This may be trivia but it is interesting to note than 
many times when I'm working on an unstrung piano & booming the board with the 
fist  to hear its innate resonace & If your face or hand is near any of the 
nose bolt holes just how powerful a blast of air comes thru there! It would seem 
that a great deal of air is continually leaking thru these holes. Might this 
be a friction loss as you describe? WOuld the effeincy of the whole mechanism 
indeed increase if the hole were sealed or eliminated or are they benificial? 
I think I'll get someone to play vigorously on My Stwy D and then I'll see if 
I can feel any significant exchange from underneath the piano around the bolt 
holes.
  Dale Erwin

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