---------------------- multipart/mixed attachment At 12:31 AM 7/28/2003, you wrote: >Ya' know...I had this same idea years ago. The idea was based on the >violin. The panels are made of different woods to cater to different >characteristics. Maple for stiffness and good high end tones, and spruce >for bass tones. I thought about this in relation to the piano. Maple is a >tougher wood than spruce. The top panel made of maple could hold crown >better (maybe), and give better high end sustain. Yeah but the panel doesn't hold crown the ribs do. >While the lower panel, >made of spruce and crowned downward, could be thinner and give better bass >response. Connect these with a tone pole and you have a pianolin. > >Would it work? Who knows...? > >Just a crazy idea I had to use up more wood and drive rebuilders crazy, not >that they need any help. > >Mike Bratcher >----- Original Message ----- >From: "Joe And Penny Goss" <imatunr@srvinet.com> >To: "Pianotech" <pianotech@ptg.org> >Sent: Sunday, July 27, 2003 8:48 PM >Subject: Re: Rib overkill > > > > ?? > > Has anyone ever made a piano with two boards. Parallel to eachother with > > different stiffness factors? > > Joe Goss > > imatunr@srvinet.com > > www.mothergoosetools.com > > ----- Original Message ----- > > From: "Ron Nossaman" <RNossaman@cox.net> > > To: "Pianotech" <pianotech@ptg.org> > > Sent: Sunday, July 27, 2003 7:28 PM > > Subject: Re: Rib overkill > > > > > > > > > It can. A more flexible board will tend to be generally louder, with > > > shorter sustain. A stiffer board will tend to be not as loud, with >longer > > > sustain. > > Will the bass suffer? > > > > > > Yes. If there is to be any hope of getting a fundamental out of the= low > > > bass, the board needs to be flexible down there, and the back scale >needs > > > to be long, and the core wire needs to not be the diameter of an 8d >nail. > > > At the same time, the treble needs to be stiff or you will get the > > > percussive attack and short sustain of the "killer octave" through the > > last > > > two octaves or so. Stiffness requirements are widely different from= one > > end > > > of the scale to the other. > > > > > > > > > >I think I also remember Del mentioning something about a board giving >too > > > >much of a percussive sound and not as much string sound. Is this= with >a > > > >board that is too stiff? > > > > > > Probably too flexible. > > > > > > > > > >How does the thickness of the board relate to how much load it can > > support? > > > > > > It depends on the crowning method. A compression crowned board will be > > > stiffer with a thicker panel, and support comparatively more load than= a > > > compression crowned board with a thinner panel. With a rib crowned >board, > > > assuming it is really rib supported and not just a compression crowned > > > board with machine crowned ribs, the panel thickness makes much less > > > difference. With a rib crowned, rib supported board, there is no need >for > > a > > > thick panel if the rim is solid. > > > > > > > > > >And in relation to the rib thickness? > > > > > > Again, it depends on the crowning method. Compression crowned boards >tend > > > to have ribs wider than they are deep, because they start out flat and >the > > > > > panel expansion has to bend them to form crown. Rib crowned and >supported > > > boards will have ribs less wide, and deeper, regardless of panel > > thickness. > > > Ribs get stiffer in proportion to their width, and to the cube of= their > > > height (and inversely to the cube of their length), so a little bit of >rib > > > height makes them a lot stiffer. > > > > > > > > > >I'm sure all these things are interrelated. What are the trade-offs? > > > > > > Those are some of them. > > > > > > > > > >Next, I'm sure the size of the board is a factor. A smaller piano= will > > > >have more support from the rim, because the there is more rim per= area >of > > > >board. Yet another factor to consider, aye? > > > > > > Absolutely. Soundboards, contrary to manufacturers' marketing= literature > > > bragging about how their soundboards have more area than their > > > competitors', are for the most part already too big. Redesigns I do > > > typically lose something around 20% of the existing active soundboard > > area, > > > depending on what I started with. > > > > > > > > > >How does one judge or weigh the trade-offs? There are so many >variables. > > > > > > A bunch of variables, the most critical of them not the ones we have > > always > > > been taught were all important. One can either put in a couple of >hundred > > > soundboards, making incremental-to-major changes in virtually= everything > > > until he works out a set of priorities and effects of design features, >or > > > he can do what I did and start rethinking what I thought I knew= against > > the > > > good fundamental science and physics based advice and guidelines of > > someone > > > who did do the basic R&D from scratch. That would be Del. > > > > > > > > > >There's no real point here to my questions. I am always trying to >learn > > > >more about my trade. And who else do I learn from other than the= folks > > > >who do this every day? > > > > > > > >Mike Bratcher > > > > > > Every day's a new day for all of us isn't it? There's always something >to > > > learn - and heal up from. > > > > > > Ron N > > > > > > _______________________________________________ > > > pianotech list info: https://www.moypiano.com/resources/#archives > > > > _______________________________________________ > > pianotech list info: https://www.moypiano.com/resources/#archives > >_______________________________________________ >pianotech list info: https://www.moypiano.com/resources/#archives Greg Newell Greg's piano Fort=E9 mailto:gnewell@ameritech.net=20 ---------------------- multipart/mixed attachment--
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