Hi Jim. Thanks for the post. I understand your bottom line of course. The point that has been raised to me is off on a somewhat different track tho and I'd like your thoughts on it. Regardless of the overall stiffness of the bass end of the soundboard... if the cross grain stiffness gets too different from the along the grain stiffness... can this cause the boards resonance capabilities to break up into many smaller areas and hence inhibit low end response ? I'm going to take a couple quotes from Conklin and Wogram below for your edification on this thread.. Particularly Wogram points in the direction I am thinking along here. "The modal frequencies are determined by many factors, the primary ones being the material, size and shape of the soundboard, its thickness and grain direction, and also the material, dimensions, and placement of its ribs. Secondary factors include the characteristics of the rim or case to which the soundboard is attached. In general, the thicker the soundboard, the louder the piano but the less the duration of its tone. Soundboard design is often a compromise." -- Conklin "A stiffening of the soundboard would improve the sound radiation efficiency, as a stiff soundboard is less inclined to subdivide into small vibrating areas. One purpose of the ribs is precisely to stiffen the soundboard, which indeed is thin in proportion to its size. Another purpose is to "homogenize" the soundboard by equalizing the difference in bending stiffness (elasticity modulus) parallel to and across the grain." -- Wogram Jim Ellis writes: I have been "reading the mail" on this subject, and I see a tendency to over-simplify. There is no single answer. It's a very complex issue. Begin with the soundboard modes themselves before any stringing. After stringing and full tension, everything changes. Down-bearing, string-tail length, board mass, board stiffness (including ribs), and the possibilities go on and on. The "bottom line" is, what is the compliance and the resonant frequency of the board after all is said and done? At what frequencies do the board's vibrations break up into standing waves, and where? Whatever the resonant frequency is, and how wide or narrow its bandwidth is will determine the dominant part of the tonal spectrum. I would not dare try to tell you what the solution is, because the problem is so complex. But the general "rule-of-thumbs" is: The stiffer and less compliant the bass-end of the board is, for whatever reason, the less low-frequency response it will have. The more compliant it is, the more low-frequency response it will have, but the faster those low frequencies will decay. Sincerely, Jim Ellis
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