Stephen Birkett wrote: > It all comes down to the forces involved. Agreed that modern tensions and > downbearing have the potential to destroy the cellular structure of the > board. But this comes down to good and bad design, not the method. My point exactly. Modern pianos are not the same as the instruments you refer to. And any comparisons you wish to make must be taken in that light. My comments refer only to those instruments of so-called "modern" design. A method that may have been appropriate for one type of instrument may not be appropriate for another. If you say that compression crowning works for the instruments you are involved with, I'll not challenge that. I have no experience with them. It has serious limitation in the instruments I am involved with. I have articulated many of those limitations in previous posts. You don't generally try to make apple pie with peaches. And we don't use wood spokes on automobile wheels anymore, either. Stephen Birkett wrote: > ...250 years, or more if you count those harpsichord sbs that were > "compression"-crowned in this manner. Although crown, for the sake of it, > was not the objective back then. Rather the idea of pre-stressing the > soundboard membrane, and that could be achieved in quite different ways on > the earlier instruments (e.g. case compression while gluing in the sb, > resulting in a board under tension not compression). > > In fact there are many examples of early pianos with sbs crowned by either > compression (i.e. differential drying of panel and ribs) or curved ribs, > or combinations of these. Some early ribbing patterns were such that > differential drying could *not* have been used and when you take ribs off > these beasts (1800, 1820, 1850 etc.) you can observe the radiused rib > profile. So nothing is really new about either method. They are both > tried and trusted. The application of the method in a particular case is, > however, a design decision that stands or falls on its own merits. Ditto the above. The instruments you discuss are not built the way the so-called "modern" pianos are built. The wood is not subjected to the same loads and stresses. In none of the instruments you discuss are the internal compressive forces within the soundboard panel even close to those that are generated in the instruments the rest of us are involved with. My comments may or may not apply to the instruments you refer to. There are far too many variables involved for me to make that kind of direct comparison. The two types of instruments are fundamentally different designs and have different materials and design requirements. Again, apples and peaches. Regards, Del PS. About Marilyn Monroe, you'll have to ask Andre. You'll have to admit, though, she was at least as interesting as pianos are.
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