Oops... Re: Unusual rib structure?

[Greg Newell]

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Del,
         'Tis a pity that this experiment will have to wait until I am a=20
great deal more flush with cash. Surprising that the piano makers of the=20
world aren't running these experiments in an effort to perfect their own=20
designs.

Greg Newell


At 04:56 AM 5/8/2003, you wrote:


>----- Original Message -----
>From: "Greg Newell" <gnewell@ameritech.net>
>To: "Pianotech" <pianotech@ptg.org>
>Sent: May 07, 2003 8:25 PM
>Subject: Re: Oops... Re: Unusual rib structure?
>
>
>Del,
>          Can this type of modal experiment be reproduced? and if so, how?
>
>Greg Newell
>
>
>--------------------
>Sure. In fact it would be much easier today than it was then--computers are
>much faster and the software is much more sophisticated. All you need is a
>piano with a suitable soundboard set up so you have access to the
>soundboard at specific intervals. As I recall we used a grid of
>approximately 3" spread across the board. If you want the results to be
>meaningful this means that the piano must be strung. Yes, you want to get
>to all parts of the soundboard so that means drilling some holes through
>the plate. You mount a suitable accelerometer on the bridge at some
>suitable location. Using a Modal Hammer (i.e., a hammer of known mass and
>with an accelerometer and a force transducer on its striking surface) you
>tap the soundboard at each grid point with as much consistency as possible.
>Once all the data from these hammer impacts has been recorded you process
>the whole thing through some very expensive Modal Analysis software. For
>your trouble you will get a picture of the soundboard panel vibrating in
>slow motion at whatever frequency or frequencies you desire. Then, of
>course, you have to interpret what you see. Interesting stuff. But pricey
>and time consuming.
>
>Del
>
>_______________________________________________
>pianotech list info: https://www.moypiano.com/resources/#archives

Greg Newell
Greg's piano Fort=E9
mailto:gnewell@ameritech.net=20

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