I don’t know—did you? I’ve cut and pasted the post in which it first appeared below: Look at the drawing below. Ribs #2 and #4 extend across the width of the working portion of the soundboard. The low end of the bridge has an extension that goes over the floating portion of the soundboard liner. These three ribs provide all of the stiffness the area around the bass bridge needs. The rest of the ribs are all sized to provide the necessary stiffness to the area around the tenor/treble bridge. In the Fandrich piano the ribs that terminate in the Z-Bar—i.e., ribs #5 through #13—are set into notches in either the Z-Bar or the soundboard cutoff bar. The lower ribs—#1 through #4—terminate about 10 mm in from edge of the soundboard panel. The M rim set up against the soundboard assembly do highlight the Z-Bar but this is not quite how the Z-Bar works. The Z-Bar presents a very rigid termination to the soundboard panel in the area around the treble end of the bridge. The further down the scale you go the Z-Bar its termination impedance decreases—its stiffness decreases--allowing the edge of the working portion of the soundboard to move with increasing freedom. The termination impedance of the soundboard panel varies with the frequency of the energy waves traveling across the soundboard assembly; the fundamentals and lower partials are affected more by the stiffness—which is decreasing down the scale—of the Z-Bar while the higher partials are affected more by its mass which also decreases further away from the point where it is solidly fixed to the back assembly. The soundboard assembly actually appears larger to the fundamentals and lower partials; smaller to the higher partials. In practice this has the effect of increasing the dynamic range of the instrument through the tenor section of the piano. The Z-Bar also adds both stiffness and mass to the area around the tenor end of the bass bridge. By coupling the ends of the Z-Bar and the bass bridge together the bass bridge extends the effectiveness of the Z-Bar further down the scale keeping the effective area of the soundboard relatively smaller than it would otherwise be which improves the efficiency of the soundboard around the low end of the tenor bridge. The bass bridge is able to take advantage of the entire soundboard area in the lower half of the soundboard assembly. That’s the short version and I think I got it all straight. It’s late and it’s been a very long day—I’ve been moving shop equipment and tools and other stuff—so I’m not guaranteeing anything. I’m sure if I got something turned around someone will be happy to point it out to me…. ddf Delwin D Fandrich Piano Design & Fabrication 6939 Foothill Court SW, Olympia, Washington 98512 USA Phone 360.515.0119 — Cell 360.388.6525 <mailto:del at fandrichpiano.com> del at fandrichpiano.com — <mailto:ddfandrich at gmail.com> ddfandrich at gmail.com From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Dale Erwin Sent: Thursday, May 24, 2012 1:24 PM To: pianotech at ptg.org Subject: Re: [pianotech] David Love--Centering the bridge--was S&S something er other Did I miss a picture of this? Dale Erwin... RPT Mason & Hamlin/Steinway/U.S pianos <http://www.Erwinspiano.com> www.Erwinspiano.com 209-577-8397 -----Original Message----- From: Delwin D Fandrich < <mailto:del at fandrichpiano.com> del at fandrichpiano.com> To: pianotech < <mailto:pianotech at ptg.org> pianotech at ptg.org> Sent: Thu, May 24, 2012 1:14 pm Subject: Re: [pianotech] David Love--Centering the bridge--was S&S something er other Well, that is what most of this conversation has been about. At the time I was designing the 122 Fandrich vertical piano it seemed logical to me (and it still does) that it would be desirable to place the driving energy source of the vibrating diaphragm—i.e., the bridge—relatively close to the middle of the working part of the soundboard and its supporting ribs. The energy wave starts there and moves away from both sides of the bridge on across the soundboard to the mounting points and it seems a good idea that both arrive at more-or-less the same time. Since this was a new design and I could do anything I wanted I did so and was pleased with the results. It’s one of the best treble sections I’ve designed for any piano of any type. This was, to my knowledge, one of very few pianos that have been built with the treble section designed so the bridge could be placed relatively close to the center of the ribs. At least I can’t recall seeing any others. The physical construction of the grand piano makes it impossible and I don’t know of any upright piano designs that attempted it though there might well be some. As may be, I got a combination of power and sustain out of this design that was noticeably better than anything I’d done previously. And this with relatively light and un-juiced hammers. ddf Delwin D Fandrich Piano Design & Fabrication 6939 Foothill Court SW, Olympia, Washington 98512 USA Phone 360.515.0119 — Cell 360.388.6525 <mailto:del at fandrichpiano.com> del at fandrichpiano.com — <mailto:ddfandrich at gmail.com> ddfandrich at gmail.com From: <mailto:pianotech-bounces at ptg.org> pianotech-bounces at ptg.org [ <mailto:pianotech-bounces at ptg.org?> mailto:pianotech-bounces at ptg.org] On Behalf Of Gene Nelson Sent: Thursday, May 24, 2012 9:37 AM To: <mailto:pianotech at ptg.org> pianotech at ptg.org Subject: Re: [pianotech] David Love--Centering the bridge--was S&S something er other Yes indeed. Can you talk a bit about the treble bridge as well? Without your redesign work the bridge would also be located near the end of a rib – not so desirable up there. _____ -------------- next part -------------- An HTML attachment was scrubbed... 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