----- Original Message ----- From: "Phillip Ford" <fordpiano@earthlink.net> To: <pianotech@ptg.org> Sent: August 23, 2003 12:01 AM Subject: Re: Overs laminated soundboard > > > >>There are several compelling reasons why I believe the laminated > >>panel is superior to the solid version.....cracks in a laminated > >>panel are almost unheard of. > >> > >>So the laminated panel, with cross grain which is much less prone > >>to change dimension with hygroscopic variations, will result in a > >>panel which is more stable regarding tuning stability. After having > >>some experience with laminated panels, and after finding that there > >>is almost no shrinkage of the panel when dried down to 6% moisture > >>content, I would doubt if CC boards could be made using laminated > >>panels, since to achieve any noticeable crown, one would almost > >>certainly have to crown the ribs. > > > >I think you're right that CC methods wouldn't work with a laminated > >panel. That would depend entirely on the grain orientation of the various lamiae. If they were all in line it would still be a laminated panel and it would be possibe to make a compression-crowned soundboard system with it. Of course, it would still be subject to the same structural problems a solid panel would suffer. > > > >I also agree that a laminated panel seems superior to a > >solid panel for a host of reasons. From a performance standpoint, > >the only reason that I can think of to use a solid panel is that it > >might be better sonically. I can imagine that this might be true, > >but I can't imagine what the reasons would be. I suppose the only > >practical way to establish this is pianists ears. If they say that > >there's no discernible difference, or that the laminated panel > >sounds better, I see no reason to use a solid panel. Some low end > >manufacturers might prefer solid panels, since I imagine they might > >be easier and cheaper to make. I wouldn't think the difference in > >price would be a consideration for a high end maker. I have been on record for a number of years on this issue. In my experience pianos using laminated panels can, and have, outperformed otherwise identical pianos using solid panels. I've written a number of posts on this issue. > > >This topic of grain orientation has been discussed before. It's not > >clear to me that there is any inherent advantage in orienting the > >grain along the bridge. I can't think of a structural reason. Once > >again, the only reason that I can imagine is a sonic one. Personally, I think this is a holdover from the compression-crowning technology. We have been deviating from this convention for many years with solid panels. In general (and taken to its extremes, but with all other factors remaining equal) a soundboard panel with a grain angle closer to perpendicular to the bellyrail will have a better treble response but a poorer bass response. One with a grain angle running closer to parallel to the bellyrail will have a poorer treble response but a better bass response. Consider the effect of grain angle on the stiffness of the soundboard system at the bridge(s). > > >Perhaps > >the board behavior is influenced in some significant way by the > >panel grain direction. Or perhaps it's not so much the absolute > >grain direction, but the grain direction relative to the orientation > >of the ribs. It is both. I can't remember the last time I designed a soundboard with the ribs running perpendicular to the soundboard grain angle. Consider the effect of each--separately and in combination--on the mobility of the bridge(s). > > >I've certainly seen many older pianos with various > >grain orientations. But they generally seem to have the panel grain > >nominally perpendicular (more or less) to the ribs. Perhaps things > >were set up in this way because they were using the ribs to help > >crown the board. I believe this to be the case. Del
This PTG archive page provided courtesy of Moy Piano Service, LLC