Radiation modes and acoustic field confined near acoustic sources.

A method to confine the acoustic pressure distribution near a loudspeaker array is investigated for potential application to personal audio devices. The surface velocity distribution of the loudspeaker array is determined so that more reactive than active acoustic power can be generated. The design is based on the theory of radiation modes, i.e., surface velocity distributions that independently contribute to the complex acoustic power. A computer simulation is conducted for a rectangular array of pistons in an infinite baffle, and it is shown that a locally confined acoustic field can be achieved as expected.