> In general it would be better if >they were higher in frequency. For example if the lowest mode were tuned >to 100 Hz instead of around the 50 Hz more commonly seen. Unfortunately >to construct such a soundboard would make it too heavy and it's >impedance would be too high. Hi John, Let's see, the resonant frequency of an oscillating system goes up with increased stiffness, and down with increased mass, while the impedance goes up with increased stiffness and up with increased mass. Is that right? If so, then the resonant frequency of the soundboard in the bass could be raised by lowering the weight, and slightly increasing the stiffness. Narrower, taller ribs could provide the same, or slightly greater stiffness at a lower weight. Theoretically, this could raise the resonant frequency without raising the impedance. Thinning the panel in the bass would decrease both weight, and stiffness, as well as lowering the impedance, but I'm not sure what it would do to the resonant frequency, since I don't know what the sum proportional effects of the changes are. I suspect the information is out there somewhere, but I haven't tried chasing it down yet. It's on the list. Any ideas? Ron N
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