----- Original Message ----- From: <A440A@AOL.COM> To: <pianotech@ptg.org> Sent: March 03, 2002 3:43 AM Subject: Re: Chines and multi-piece rims > Del writes (and confuses me): > > >The continuous bent rim has certain manufacturing advantages but it has > >no acoustical advantages that I am aware of. > <big snip> > >So, having said all that, there is at least one compelling reason for my > >use of a multi-piece rim: its potential acoustic superiority. I can better > >shape the treble soundboard and I can more easily float the bass end of the > >soundboard. > > Greetings, > Perhaps I am reading it wrong, but these two statements seem to be taking > different paths. Not really. We are used to the idea of the continuous bent-lamination rim being somehow inherently superior to the mult--piece rim. Yet I have never heard anything approaching a compelling argument proving -- or even explaining adequately -- this supposed acoustical superiority. > > Does "its potential acoustic superiority" refer to the > geometry it makes possible? This comment refers to the soundboard's shape and size. > > I don't think we can discount the acoustical importance of the rims, since > they are not only massive, but are entrained via their connections in the > string-bridge-soundboard-case-plate-string -etc circle. Wouldn't the > "impedance" of the rim have a measurable effect? I am not discounting the acoustical importance of the rim. I'm emphasizing it and capitalizing on it. Yes, the impedance of the rim is measurable. But a multi-piece rim can be built with just as much mass and stiffness as a continuous bent-laminate rim. > > I know we can use uprights > with their jointed constructions as a case in point, do they have the same > output as a continuous wrapped grand? They certainly can have. Our 122 cm vertical easily matched or exceeded the power and sustain of a certain well-known 5' 10 1/2" grand. > > Would it be fair to draw comparisons > with the Lucite cased grand that has been on display (or did it have a wooden > inner rim?) I've not studied the structure of pianos using Lucite casework. Nor have I spent a lot of time listening to them. > > (I have never installed a soundboard, or untwisted a case, but I have sure > sat in front of'em for a long long time) I've never untwisted one either. I'm not sure it would be possible. Or necessary. Del
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