Del, Phillip and list, > > Your device addresses >> these problems. I do also worry that the separate 'bearing >> rod' held in place by string pressure (if I understand your >> sketch correctly) might buzz. Del replied; >I wasn't able to do enough experimental work and/or testing to determine >this. I heard no hint of buzzing on the Stuart piano. That's true Del, but I suspect he has had problems with earlier pianos. The Stuart agraffes now have a small block of silicon rubber located between the 'string hold down pin' and the string termination bars, and I suspect its not there for looks. I remember checking the very first piano he built and it had buzzing agraffes. I can well understand how you may missed the rubber blocks Del, it so difficult to take in every aspect of a design in fifteen minutes. I've had the luxury of having a few sessions with these pianos. We're now maintaining a recent piano at the Sydney University Great Hall. It seems to me that the idea of controlling the buzzing with silicone rubber would be a wonderful way to pull energy out of the vibrating string to shorten sustain. I like the idea of the bridge agraffe, but there certainly are some engineering obstacles to be overcome if they are to be effective termination devices. I don't think the Stuart design addresses the problems appropriately, but that's just my view. The other negative aspect of bridge agraffes is the resultant loss of bridge wood height. I've written before on the list about the influence of bridge height on the sustaining qualities of an instrument. The Stuart string height is 32 above the sound board panel (long bridge ie.), while his agraffes hold the wire 8 mm above the bridge wood. With only 24 mm of bridge wood height, I believe the note to note sound board impedance will be less uniform. I have seen just two concert grand pianos from different makers with 24 mm high bridges. I didn't care for the tone of either, and I hold the bridge height accountable for part of the crime. Look up the five lectures on the acoustics of the piano. http://hem.fyristorg.com/5_lectures/ It is some years since I read these documents, but they certainly mention the negative effects of building sound boards with lower ribs. I am convinced that the bridge height is just as important an issue. The idea you suggest Phil would certainly solve the potential buzzing problem, but I share Del's view that it would make stringing a little more difficult. I've been playing around with a few ideas in this area too, but so far nothing's hit the 'go' button. Ron O -- ______________________________ Website: http://www.overspianos.com.au Email: mailto:ron@overspianos.com.au ______________________________
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