Sounding board

Abstract: A grain sensor comprises a piezoelectric element mounted to a rear surface of a relatively thin, flat sounding board of substantially greater surface area than the piezoelectric element. Forces experienced by the sounding board due to grain particles impinging upon the front surface thereof are imparted to the piezoelectric element. A rigid frame surroundingly engages side edges of the sounding board. The rigid frame includes an inwardly extending flange for substantially covering a peripheral edge portion of the front surface. A base member having a surface substantially congruent with the sounding board surfaces is mounted in facing relation to the rear sounding board surface for substantially enclosing the piezoelectric element therebetween. A resilient seal and spacer member is interposed between the facing surfaces of the sounding board and the base member.

Abstract: An adjustable game call apparatus includes a sounding board, an air passageway formed in the sounding board, and a vibrating reed positioned within the air passageway adjacent the sounding board. A pair of guide posts extend upward from the sounding board to receive a pair of cut-out areas formed in the reed. The slots and posts allow the reed to be longitudinally adjustable relative to the sounding board of the game call apparatus. Another aspect of the game call apparatus comprises a moisture diverter system which involves a plurality of diverters formed in the sounding board to direct moisture away from the reed and toward a trough formed in the sounding board. The diverters also provide a precision tuning system for the game call to ensure the full high and low ends of the desired range of tones are produced by the game call.

Abstract: In this study, variation in acoustic properties of Arizona cypress wood was monitored from pith to bark as affected by tapering of the growth ring width. Specific modulus of elasticity, acoustic coefficient, damping, and acoustic conversion efficiency were calculated. It was shown that the outer parts of the stem, close to the bark containing narrower growth rings, exhibited lower damping due to internal friction and higher sound radiation. Our finding theoretically justified the luthier craftsmen’s traditional preference toward timbers with narrow growth rings to make sounding boards in musical instruments.