Hi Calin, >I think Stuart's claim regarding longer sustain is quite correct. I heard >his piano on recordings compared with other famous concert grands. The same >piece was played on different pianos by the same pianist. The Stuart piano >struck me as having probably the longest treble sustain of them all. > >I believe longer sustain is a direct consequence of using bridge agraffes, >as I tried to explain on my website and in my other replies to this thread. >Simply because you loose less energy with a bridge agraffe and put it to >better use because of its large footprint. While I agree the improvement in sustain may in part be due to less energy being lost, when compared to lossy bridge cap wood, I still suspect that the added mass may be of more significance than the termination improvement. I am inclined to this opinion since we gain very large increases in sustain time by mass loading an otherwise conventional bridge. >What I'm trying to say is that it's not only the increased mass that >accounts for the longer sustain, it is the stiffness of the agraffe which >allows it to transmit much more of the string's energy to the soundboard. >The traditional termination looses too much of it at the string/wood >interface. Perhaps so. >. . . However, mass is not the only factor when using bridge >agraffes. Otherwise, >one could mass load a bridge imagine adding weights to the treble end. One can, and we do. >Maybe they will improve sustain a bit, but not as much as a bridge agraffe, >because the string still bears on wood. I can tell you from experience that adding mass to the treble end increases the sustain by a considerable amount. At this point in time I haven't done A-B tests with two instruments, one with agraffes and one with a standard bridge mass loaded. But I can tell you that we have direct experience of deliberately mass loading the treble to arrive at a desired balance between sustain and power. Here's an image of a re-manufactured piano which was mass loaded in the treble for this very reason. http://members.optusnet.com.au/ronovers/overskawai8r.jpg This piano was re-manufactured for the pianist, Gerard Willems, who has done a number of recordings using the Stuart piano here in Australia. Gerard had a Yamaha G2 in his home studio which was worn out. When he asked me about the possibility of rebuilding it for him I suggested finding a Kawai KG5 shell to re-manufacture it with our action and I-rib board with a new scale. We routinely mass load the high treble to achieve the sustain we're looking for. Those of you who saw our no. 6 piano at Rochester would have seen the mass loaded bridge. > And the string/wood interface is >inherently flexible and absorbs much of the string's energy rather than >transmitting it to the soundboard. The agraffe improves sustain because it >offers a clean termination, high stiffness (=little loss within it) and >transmits the string's energy via a large footprint to the bridge. >Just look at the footprint of a bridge agraffe and compare it to the >footprint of a string on a wooden cap. The difference is huge. Yes, I agree that the larger and less lossy footprint probably does allow for more of the higher harmonic spectrum to be transmitted to the board, but I am still unsure if we want that to occur from a musical perspective. My impression from speaking with Udo Steingraeber, when he was here a few months ago, was that he was not yet convinced that the agraffed version of his concert grand is suitable for all repertoire. But I'm sure many of us are unfamiliar with the qualities which bridge agraffes bring to the mix, since most of us haven't had a lot to do with instruments which are fitted with them. Even in Udo's case, he is mostly used to building instruments with conventional bridges. But I was interested in his impressions since he is one of the few people on the planet who has built instruments with conventional and agraffe equipped bridges. >By the way, I'm always talking about the treble end because that is the >place where sustain is insufficient even in the best pianos. >Lower down the scale, the situation changes, as the frequencies to the >transmitted are lower and the string/wood interface becomes less of an >issue. It can transmit lower frequencies much better than high ones. I agree. As I mentioned in a previous post. I believe that bridge agraffes should be given serious evaluation as a possible way forward in piano evolution. Ron O. -- OVERS PIANOS - SYDNEY Grand Piano Manufacturers _______________________ Web http://overspianos.com.au mailto:ron at overspianos.com.au _______________________
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