On 5/30/2012 4:14 PM, Gene Nelson wrote: > > As diaphragmizing soundboards has come up I will throw out my novice > thoughts: Why is it that the bass/lo-tenor area of the board is always > diaphragmized? > Why not the treble? Steinway does diaphragm the treble. Typically, you don't want the treble to be too flexible. You need a low amplitude excursion stiff board, like a tweeter in a stereo system. In the bass, you want a high amplitude movement, and much more flexibility to accommodate the low frequencies. I float the tail of the panel in pianos 6' and under to get the required freedom of movement and flexibility. It's more effective than diaphragming. > Seems to me that for an radius crowned board that has very little > compression, it is the ribs that respond/restore the board that is displaced > by string/hammer energy and a more massive board should tend to bring out > the fundamental more efficiently - conversely a less massive diaphragmized > part of the board in the treble would be less massive and tend to bring out > these higher frequencies??? Actually, the lighter the assembly overall, the better in my experience. I drill big holes in the bass bridge to keep it as light as I can. Too much mass and it starts sounding sort of clangy and muffled. Flexibility seems to be the first concern in the bass. The treble, as long as the minimal stiffness requirements are met, responds better to mass, and the addition of mass can save a treble that was built too stiff, giving you a kind of get out of jail free card while you're looking for a near optimal treble setup. Too much mass quiets the treble too, but nothing I know of can save a too flexible treble. It's just going to dink. Ron N
This PTG archive page provided courtesy of Moy Piano Service, LLC