Ron: Why could Stephen Paulello's bridge agraffe design not be used for trichords? A set of holes could be drilled to allow a middle string to be installed. Granted, installing it would be a minor pain, but it could be done. dave __________________________________________ David M. Porritt, RPT Meadows School of the Arts Southern Methodist University Dallas, TX 75275 ----- Original message ----------------------------------------> From: Overs Pianos <sec@overspianos.com.au> To: Pianotech <pianotech@ptg.org> Received: Tue, 23 Sep 2003 17:41:45 +1000 Subject: Re: String vibrations (was Re: Stuart) >>At 8:25 AM -0700 22/9/03, Joseph Garrett wrote: >>It seems that the better sustain and clarity of the bridge agraffe is not >>due to the direction of the vibration, but simply because it provides a >>better termination (all metal) than the conventional bridge pin and wood >>termination. >>What do you think? >Hi Joe, >Yes, I suspect that when the agraffe is firmly fixed to the bridge >(and they don't seem always to be, since they can exhibit falseness >as well), they will produce a cleaner tone with better sustain than a >conventionally pinned bridge. Like Phil Ford, I don't subscribe to >the theory of any termination being capable of influencing the mode >of vibration. Furthermore if it did, as Phil also mentioned, this >would lead to a reduction in sustain with a higher initial sound >pressure level. While I have no doubt that a properly executed bridge >agraffe system could be very good, I suspect that some of the claimed >benefits attributed to it is just 'smoke and mirrors'. >Two things worry me about using bridge agraffes (I admit that I am >interested in using them at some point). >The first is that the agraffe takes up valuable bridge height. If, >for example, the string plane is say 8 mm higher than the bridge on >account of the agraffe taking up the space, a piano with such an >agraffe will have only 24 mm high bridges if the string plane is 32 >mm above the panel. I consider 24 mm as an inadequate height for the >long bridge, and all pianos which I have so far experienced with such >low bridges seem to exhibit tonal problems. Therefore, the bridge >agraffe should be designed with the lowest practical height between >the top of the bridge and the string plane. Alternatively, one could >build a panel with another bridge under the sound board as Grotrian >did with some of their early grand pianos, but this would push the >cost of the piano up quite a bit. >The second concern I have with using bridge agraffes is fixing them >permanently to the bridge. Of the bridge agraffed pianos I have >heard, I suspect that this can be a problem. It may be possible to >achieve a good connection by using West system glue between the >agraffe and the bridge, and using machine screws to secure the >agraffe to the bridge, while at the same time gluing them into the >bridge with West system. Stephen Paulello's agraffes are glued to the >bridge. Take a look again at the following close-up image of his >agraffe. A light blue adhesive can be seen at the junction of the >agraffe with the bridge. >http://www.overspianos.com.au/plello1.jpg >Notice also that its quite a good design since it has a low height >from the bridge to the string plane. Unfortunately, this design could >not be used for trichord stringing. >Ron O. >-- >OVERS PIANOS - SYDNEY > Grand Piano Manufacturers >_______________________ >Web http://overspianos.com.au >mailto:info@overspianos.com.au >_______________________ >_______________________________________________ >pianotech list info: https://www.moypiano.com/resources/#archives
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