Topic: Patent application discussing soundboard resonance frequencies
This is a patent application for a composite fiberboard soundboard for several acoustic instruments.
The fiberboard itself may not be of much interest to us, here, but the application includes a list of the usual resonance frequencies for the soundboards of several acoustic instruments (violin, viola, piano, guitar, etc) and discusses the relation of a soundboard's size and thickness to its resonance, frequency damping, and projection. Sometimes it provides the math, and other times it doesn't. Also discusses, briefly, the effect of having low perceivable soundboard resonance freqs as compared to higher ones on the perceived harshness of the sound. (But mostly as it affects the timbre of violins.)
http://www.patentstorm.us/patents/66109...ption.html
Near the end, it references some drawings that unfortunately don't appear to be included in the Web version of the application.