Patent ID: 8433075

Claim:
A machine-implemented method for processing audio signals, the method comprising: (a) receiving a plurality of audio signals, each audio signal having been generated by a different sensor of a microphone array; and (b) decomposing the plurality of audio signals into a plurality of eigenbeam outputs, wherein: each eigenbeam output corresponds to a different eigenbeam for the microphone array; at least one of the eigenbeams has an order of two or greater; the plurality of sensors in the microphone array are mounted on an acoustically rigid spheroid; and the positions of the sensors in the microphone array satisfy an orthonormality property given as follows: δ n - n ′ , m - m ′ ≈ 4 ⁢ π S ⁢ ∑ s = 1 S ⁢ Y n m * ⁡ ( p s ) ⁢ Y n ′ m ′ ⁡ ( p s ) , wherein: δ n-n′,m-m′ equals 1 when n=n′ and m=m′, and 0 otherwise; S is the number of sensors in the microphone array; p s is position of sensor s in the microphone array; Y m′ m′ (p s ) is a spheroidal harmonic function of order n′ and degree m′ at position p s ; and Y n m *(p s ) is a complex conjugate of the spheroidal harmonic function of order n and degree m at position p s .