Patent ID: 6904154

Claim:
A method of making a resonant acoustic object adapted for operation over an operative frequency range, the object comprising a member extending transversely of its thickness and capable of sustaining bending waves over an active area of the transverse extent of the member, wherein the distribution of resonant modes of bending wave vibration over the active area of the member depends on the values of physical parameters of geometry, bending stiffness, areal mass distribution and damping of the member, the method comprising: selecting, through analysis, values of said parameters to effect a desired distribution of the resonant bending wave modes in frequency over the active area of the member, wherein said parameters are associated with at least two different directions across the active area of the member, and the values of said parameters are selected such that the frequencies of the resonant bending wave modes along one of said different directions substantially do not overlap with the frequencies of the resonant bending wave modes along the other of said different directions; and making the member having said selected values of said parameters.