The paper describes a method of using a dense array of miniature microphones (e.g. MEMS or miniature electret) to yield precise one-point multi-channel gradient microphones. The signals obtained from individual microphones in the array are used to obtain an estimate for the zeroth, first-, and second-order components of the gradient of the sound field at the center of the array. (Higher orders of the gradient tend to be too noisy for actual sound recording purposes.) These can be used to form stereo or multi-channel signals with adjustable polar patterns for recording purposes.
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