Modal Analysis

[Delwin D Fandrich]

----- Original Message -----
From: "John Delacour" <JD@Pianomaker.co.uk>
To: <pianotech@ptg.org>
Sent: December 05, 2001 3:15 PM
Subject: Re: Modal Analysis


> At 10:07 PM +0000 12/5/01, Phillip L Ford wrote:
>
> >I'm trying to think of how one could construct a test piano with a
> >clearer view of the soundboard.  My first thought was transparent
> >aluminum (a la Star Trek).  However, since I don't think it exists
> >as yet I'm still thinking.
>
> I haven't been following the modal discussion too closely, but a
> solution to this did seem fairly easy.  Since the designer has a
> pretty good idea what the downbearing of the strings on the bridges
> is going to be, surely this downbearing could be reproduced with
> seven or eight cheap hydraulic rams each having a horizontal bar
> centred on a clevis at the end of the pistons and faced with rubber
> strips.  The pressure could then be distributed in a very similar way
> over the bridges.  No?
>
> JD
>

I don't think so. There is more to it than just the physical load placed on
the bridge. The hydraulic rams could apply the down force alright but I
doubt they would have the compliance (for lack of a better word) that the
string plane has. Specifically the effect the backscale has in restraining
the motion of the soundboard assembly.

Del