Modal Analysis (was Negative bearing (long))

[Delwin D Fandrich]

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  Yes, Richard, I have the book and I've read the article. As I have =
said several time, my experience was some different.=20
    Del


  Sorry if I seem er.... eager to help..... but it seemed like you said =
you had very limited experience with Wograms experiment and had little =
knowledge of his work and that you based your tentative skepticism to =
modal analysis on just one piano and that on the other hand you had =
learned quite a bit from that one experiment about soundboards in =
general... all that seemed just a little vague so I threw this out.=20

I said I have no knowledge (other than what he has written) of Wogram's =
experiment. And that, while my knowledge of modal analysis is limited, I =
do have some knowledge of, and experience with, modal analysis in =
general. I did learn a lot from the work I did on the project. Yes, it =
was with just one piano, but it is my understanding that Wogram was also =
discussing just one piano. That results of work I did differed in =
important ways from those of Wogram's.=20

 =20

  you reply to Phil kind of matter of factly about this again when you =
say...=20
   =20

    "I can't see any advantage to this. Other than as a teaching aid to =
help=20
    understand how the soundboard works. It is only going to illustrate =
at what point the soundboard resonances come in and what their shapes =
are. Again, this is with an unloaded board. Everything is going to =
change once the strings go on and their up to pitch."
Please keep this in context. This was a reference to Steinway supposedly =
doing this as part of a production step.


  but you seem to be saying you have too little experience with Wograms =
work and modal analysis (haveing done just one yourself) to state this =
position as a fact...=20

No. I have no experience with Wogram's work other than what he has =
published.





  You said....=20
   =20

    "Well, as I've said, I have limited experience with the technique. =
But that=20
    was on a new grand piano I had designed and built. So I was at least =

    intimately familiar with the instrument and with what the designer =
intended to achieve with the design. I learned more about the design =
during the few days I was able to work with an engineer from B&K on the =
modal analysis project than I ever expected. It gave me insights into =
the functioning of the soundboard I doubt I'd have gotten any other =
way."
  Now I dont mean to tick you off or anything Del...=20

It sure seems like it.



  I am really just trying to get straight what your experience base is =
on this, and why you seem to feel so strongly that Wograms standpoint on =
the relationship between unloaded and loaded conditions is wrong. =20

Because my experience, and the results obtained, differed substantially =
from those he has published.



  Couldnt you describe a bit more about this example you mention =
above... what you did, how you measured both before and after and that =
kind of thing. I would also be very interested in knowing what kind of =
things you felt were valuable... you mention some insights into =
soundboard functions... what particulars.=20

No.=20



  Could any of us learn any of these same things by carrying out the =
sand experiment ?=20

Perhaps. But I'm not at liberty to be much more specific than I've =
already been.

Del


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