> -----Original Message----- > From: pianotech-bounces at ptg.org > [mailto:pianotech-bounces at ptg.org] On Behalf Of Ron Nossaman > Sent: luni, 20 noiembrie 2006 19:43 > To: Pianotech List > Subject: Re: Article about bridge agraffes - function, types > > Hi Calin, > I see it somewhat differently. The wood acts as a damper, yes, > but not for high frequencies, but rather for bleed through. Interesting point. > The short segments within a bridge agraffe are too short to > sound audibly. They are, however, long enough to transmit > string motion, via rocking on the bearing points, through to > the back scale. Quite possible. > This doesn't happen in a conventionally pinned It doesn't, but this doesn't mean that the energy that would bleed through the agraffe to the backscale is conserved in a traditional pin/cap device. It is just lost there because the string segment between two bridge pins is, in effect, a damped string segment. So the bridge agraffe appears, again, as a device that can put some of the energy lost with a traditional termination to an audible use. If the result is pleasant or not, worthwile etc, remains to be seen. But the Steingraeber piano was wonderful, so agraffes seem to have a lot of potential in the hands of the informed piano designer. > bridge, so with bridge agraffes, you get a direct relationship > between the string played, and the back scale of that note. > This is the way front duplexes work, only it's on a moving > bridge in this case instead of a more solid plate, and the > deflection angles are typically shallower in the bridge > agraffe, increasing the effect. It isn't a problem in the > lower portions of the scale because the back scale is > typically braided off down there already to prevent noise > being generated by the long back scales. I would bet that > braiding off the back scale would immediately kill that > objectionable "agraffe" noise. But then you wouldn't get the > sound from the open back scale of a conventionally pinned > bridge, hence the rubber or felt dampers in the agraffes. They > kill the bleed through noises without killing the typical and > "normal" open back scale noise. I'm not sure what you mean by "agraffe noise". Is it unwanted partials or something else? Calin Tantareanu http://calin.haos.ro --------------------
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