Calin, thanks for posting the images to your web space. They were interesting. >At 10:48 PM -0500 2/5/06, Ron Nossaman wrote: >>Yes, the string bearing is reversed, but the concept behind is that >>you don't have tension sideways on the bridge, which helps the >>soundboard vibrate more freely. >> >>Yoshi > >And how does that work? In my world, the soundboard isn't changed by >the string termination at the bridge, and will vibrate pretty much >the same with either system. The real difference is in the mass on >the bridge which, if anything, will impede the vibrational freedom >(amplitude, in this case) of the soundboard assembly by lowering >it's resonant frequency, increasing it's mechanical impedance, and >extending sustain. >Ron N Agreed Ron N. Stuart also makes the claim that the horizontal forces of the string offset affect the vibrational freedom of the soundboard. I don't believe it. >. . . a lot of speculation . . . I did put the question directly to >Wayne Stuart about a year ago . . . he [claimed] the concept was >well researched and documented mathematically by CSIRO Mathematician >Dr Bob Anderssen who did the research and that anyone who wanted to >could contact him if they wanted more infomation. To quote: > >Dr Anderssen has found out how the new coupling method is >responsible for the wonderful clarity of sound that the Stuart >pianos produce. By exploiting existing knowledge about piano sounds >and string vibration, some of it over two thousand years old, Dr >Anderssen was able to build a mathematical model of the way piano >strings vibrate. "The model reveals how, in standard grand pianos, >the strings begin vibrating vertically but change to vibrate >horizontally, parallel to the soundboard," Dr Anderssen says. > >"This change to a horizontal vibration makes the sound less >harmonious." "But, in the Stuart piano, the vibrations stay in the >vertical plane because of the special coupling method implemented by >Stuart. This gives a more harmonious and stronger sound," he said. > >Strikes me that if folks want answers to these questions then >Andersen is a good place to start... followed up by a good deal >controlled testing. Speculation... armchair or otherwise may be fun >and perhaps even thought provoking... but it remains speculation. > >Cheers >RicB Strikes me as smoke and mirrors. Notice that Anderssen built " a mathematical model". Did he build a real-world model on the bench? While Anderssen has made certain claims, there is nothing offered by either Stuart or Anderssen in the way of oscilligrams or other such results to support their claim. If they had any hard evidence it would surely have found its way into either brochures or the Stuart website. But there's nothing, just the claim. Some time ago, when a Stuart piano was at a Sydney venue that we service, I did some of my own 'research' with a sophisticated tool called a trouble lamp. I placed the lamp in close proximity to some strings on the Stuart piano and played the note to watch the vibrational mode during the string's decay. As expected, when initially struck the string vibrated in a vertical mode and as the tone changed from the initial high-level to the lower-level long decay, the mode of vibration changed to a circular mode just as it does on every other piano on the planet. Just think about it. In a regular piano the offset at the bridge is horizontal while the offset at the capo is vertical. Making the bridge offset vertical won't miraculously result in a persistent vertical vibrational mode. In any event, if it did you would end up with less sustain not more. I'm not suggesting for a moment that the bridge agraffe isn't beneficial to tone. I certainly suspect that it is, but not in the way that Anderssen and Stuart claim. At the launch of the first Stuart pianos in Newcastle, Goeff Pollard and I spoke with Robert Anderssen, and when asked about the research which was undertaken, he said that exhaustive tests hadn't been carried out. [re the Dain agraffe] Was interested to read that the agraffe on the Stiengraeber grand was a Dain invention. It is a very good design, and superior to the Stuart agraffe, which results in string noise without the silicon blocks that he uses. Mr Dain has beaten me to the public domain with this one. Ron O. -- OVERS PIANOS - SYDNEY Grand Piano Manufacturers _______________________ Web http://overspianos.com.au mailto:ron at overspianos.com.au _______________________ -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20060504/9f19766e/attachment.html
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