On 1/7/2013 8:22 PM, Jim Ialeggio wrote: > Dean wrote: > > <did you reinforce the cut end of the soundboard? Notice on Del's > designed boards specifically for bass float that he has a rib run along > the edge to provide stiffness there. > > I ran the last rib roughly parallel to bass bridge, under the > monochords, but not under the high bass. As I said though, the basic > problem, at least as I see it remained. That is the restriction in > movement remained. I did one of these little Chickerings 7 years ago, and learned a few things I'd do differently now. I moved the low bass forward, eliminating the cantilever and putting that rib at an angle so it supports A-0, but is as clear of the rest of the bridge as manageable. Still didn't get enough low bass back scale to suit me, but I got what I could. The high bass, I left about where it was and added an extension to it to take it to the next rib for support. The transition was placed so the distance from the high bass and the low transition from the rim was about the same. A bass float with a veneer cap was cut at the rim edge. I stopped using the veneer cap after this piano and made the ribbing lighter in the bass for flexibility. Now, There's no reinforcement to that cut panel edge except a little CA soaked into the end grain to discourage moisture induced dimensional changes and splitting. The added flexibility most definitely makes a positive difference. Another thing I do now that I didn't then is drill a half dozen 1" holes through the bass bridge to lighten it. That helps kill that high bass clang. > In my experiment, getting that "float" rib( as I referred to it in my > sheets) to its orientation and location required an accentuation of the > radial rib pattern. This accentuated radial pattern had its own > engineering consequences. That is, the accentuated radial pattern > created a "hub" of rib origination's near the high bass, adding > restriction there, while I was attempting to remove restriction in other > places. If you think you're making it too stiff there, adjust the rib scaling. Make the first few ribs more nearly parallel and move that bunched up area farther up scale toward the killer octave where stiffness is useful. You can smooth the angle changes out so they aren't so drastic in one area too. You can also stop rib two and four short of the treble rim if you like, for flexibility. > That's why I wonder if the restrictions imposed by the available acreage > are a checkmate. While it's true that the bass in little pianos is a big limiter, there are more moves than you're using. I find it's too easy to make the high bass too flexible and boomy like so many pianos we hear out there in the world. That's why I usually extend the high bass bridge foot out toward the rim when the original actually curved back to the big boomy middle of the board. We may not ever be able to make a 5' piano indistinguishable from a 9' piano, but we can almost surely make them sound obviously better than the manufacturer ever managed. But we still don't know how much of the problem with Terry's piano is condition rather than design. Ron N
This PTG archive page provided courtesy of Moy Piano Service, LLC