Delwin D Fandrich wrote: > --- > > I like to understand where lies the difference in tone between the 2 > > methods. > > > > > > Isaac OLEG > ------------------------------ > > Isaac, > > All other things being equal, I'm not sure there is a tonal difference > between the two types of boards. Certainly a well crowned > compression-crowned soundboard has the potential of giving a great sound > with excellent sustain. But so does the rib-crowned soundboard. Oc course this is the proverbial 2 million dollar question. And at the heart lies somewhere the answer to why Steinway continues to insist that this is the only real way to crown a board for a truly quality instrument, despite the problems that both Del and Ron and others have tried to describe for us through the years. As far as I can tell from the little German I can read even Fenner will go along with the claim that this method of crowning results in a panel that is more vunerable to enviromental conditions then so called rib crowning, tho I am not entirely sure I understand why this should be. I understood that actually machined curved ribs pressed onto panel which is set in flat caul would be most susceptible to cracking, and that both the so called natural crown and rib crown had pretty much identical characteristics thus. > > I resisted the idea of building rib-crowned soundboards for several years > after I started replacing boards for just the reason you mention -- I had > been taught that compression-crowned soundboards were inherently superior. > (They didn't call them "compression-crowned" in those days. This is a term I > made up when I started teaching and writing about two different types.) > After a couple of my early boards started developing the same problems as > those found in new pianos I made the switch. This compression crowning is not quite the same as what is refered to as "natural crown" ?. Arent these pressed into pressed into a dished caul ? It is also my understanding that this results in a panel with very stabile crown (assuming reasonably stable environment) > > I have two fundamental problems with compression-crowned soundboards: > First, they are unpredictable. Their actual crown depends on too many > variables. The starting and ending wood moisture content. The physical > characteristics of the wood used. The environment of the piano once built, > etc. > Second, they have a highly variable useful life. I have encountered > pianos with compression-crowned soundboards over 100 years old that still > sound fairly good. But I have also encountered pianos still on the showroom > floor with sustain times through the killer octave region that tuning them > would be difficult. The poor piano didn't even make it out of the showroom! > And this is in Seattle, Washington and Portland, Oregon. Two areas noted for > the particularly kind climates. Isnt this mostly indicative of either poor assembly conditions, poor handling, or lack of understanding of the vunerabilities in the process, and less indicative of that the process itself is fundementally flawed ? > In any case, I have not been able to detect any tonal differences between > the two systems that I could attribute directly to the crowning technique. > If there is a difference there are so many other variables it gets lost in > the muddle. Hmm... well I suppose if one could definitively answer the "which sounds better" question we'd be able to get beyond this issue once and for all. But to be honest... it just seems too difficult for me to accept that S&S simply insist on continuing a process that is shown clearly to be flawed when there is so obviously a better way of doing things. In spite of your very convincing reasoning, I sure would like to hear somebody with similiar competance from the opposing view stand up and take the podium. > > > Regards, > > Del Cheers RicB -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway mailto:rbrekne@broadpark.no http://home.broadpark.no/~rbrekne/ricmain.html
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