----- Original Message ----- From: "gordon stelter" <lclgcnp@yahoo.com> To: "Pianotech" <pianotech@ptg.org> Sent: May 08, 2003 3:40 AM Subject: Re: Oops... Re: Unusual rib structure? > > Why? I can see that with a proper cutoff bar. > But aren't we really saying the same thing here, with > a slightly different "angle": that they were trying to > get sound production out of an otherwise dead portion > of the board? . > T > > > The idea is to keep the available energy out of that > > corner. > > > > Del > > I'm not sure just what the theory behind these devices was (is?). I've not found anything in the literature I have available that discusses them at all. If the theory was to get sound production out of an otherwise dead portion of the board, it was a flawed theory. In no case is this a "dead" portion of the board. It moves. Unfortunately, it moves out of phase to the main speaking portion of the board. The strap across the ribs does not alter this. It does add a bit of mass and it certainly adds some stiffness and this is generally helpful. But it is not as beneficial as a full cutoff bar. Del
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