Spherical microphone arrays for analysis of sound fields in buildings

Bradford N. Cover


The features and applications of various beamforming microphone arrays, are discussed. 'Open' or 'free field' array has a diameter of 16 cm in which 32 omnidirectional electret microphones (6 mm diameter) lie on the surface of sphere. Free field array can be used for analysis of isotropy of sound fields in rooms and detection of sound leaks in walls including directions of incidence or reflections of sound waves. In the detection of sound leaks in walls, the wall contains a pair of back-to-back electrical boxes which causes increased levels at the array position arriving from their direction and boxes cause a sound leak in the wall which is detected by the array. A 10 cm diameter rigid array that contain 32 omnidirectional electret microphones (6 mm diameter) flush mounted in the surface of a hollow aluminum sphere, has the capability of smooth the white noise gain to improve the noise tolerance.


Acoustic fields; Acoustic waves; Arrays; Buildings; Microphones; Sound reproduction; Beamforming microphone arrays; Omnidirectional electret microphones; Spherical microphone arrays

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