I think the only way to determine whether or not a thesis like this holds up in actual practice is to try it out--test it, and see what happens. Of course it has to be a controlled test. In this case the only variable should be the construction of the bridge itself. Outside of a factory this is close to impossible but in the R&D department of a factory such as Baldwin once had it is possible and I've done it. The test consisted of bridges with all vertical laminations (Baldwin's standard construction), vertically laminated bodies and solid maple caps (Steinway's standard construction) and all horizontally laminated bridges (inspired by Kimball). These were all in otherwise standard Baldwin Hamilton pianos. OK, not the best sounding piano on the planet but they were readily available and reasonably consistent. We--a variety of testing pianists--could discern no tonal differences at all that could be either heard or measured (with what was then a state-of-the-art HP FFT spectrum analyzer driven by an industry standard B&K accelerometer). After trying for some time--without success--to find some discernable performance variation among the various types of bridge the project was ended. Delwin D Fandrich Piano Design & Fabrication 620 South Tower Avenue Centralia, Washington 98531 USA del at fandrichpiano.com ddfandrich at gmail.com Phone 360.736.7563 -----Original Message----- From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Roger Gable Sent: Monday, September 20, 2010 6:40 PM To: pianotech at ptg.org Subject: Re: [pianotech] YC Capo Bars Del, I believe your correct to assume that cost is the driving factor for using horizontally laminated bridges. In reading the various responses I believe there is a consensus developing as to the pros and cons of laminated bridges and bridge caps. The beginning of this thread started off on the wrong foot when it was discovered that we were not all talking about the same thing -- bridge caps verses bridges. That being solved, this is what I believe can be derived at this point from the thread. Laminated caps are a plus to the stability of tuning and the development of false beats. The selection of different materials will always be debatable, but the concept is a plus for the piano industry. From the description of construction, the cap, having thin laminates adhered to under great pressure, essentially create a solid unit. The resin form a single unit where the layers of the saturated wood impose little reflective character within the laminate. But the horizontally laminated bridge is a different "animal". Horizontally laminated bridges have be constructed, up to now, by using a thicker wood laminate where the resin doesn't penetrate the various layers of wood as much as the capping system This would create problems with tonal development because of my submarine analyst, where energy waves would be reflected at each laminate. It would be reasonable to assume that the vertically orientated laminated bridge has the opposite effect, whereas the energy has a clear uninterrupted path to the soundboard. What do you think? Anybody? Roger Gable P.S. I'm off to a chapter meeting
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