ASA 124th Meeting New Orleans 1992 October

1pPAb6. Reciprocal technique for determining the sound radiation due to loudspeaker enclosure vibrations.

Bradley M. Starobin

Sevag H. Arzoumanian

RH Lyon Corp., 691 Concord Ave., Cambridge, MA 02138

The contribution of enclosure-borne sound to a loudspeaker's total radiated sound was determined indirectly by a combination of analytical and experimental techniques. The transfer functions that relate a loudspeaker enclosure's average vibratory response both to point force excitation and to external acoustic excitation were determined experimentally for several different enclosure prototypes. A reciprocity relation that equates the radiated pressure to force transfer function, which was not measured directly, to the acoustically induced vibrational velocity to point source volume velocity transfer function, determined experimentally, was used in evaluating the loudspeaker enclosure radiation resistance. Finally, enclosure-borne radiated sound power, as derived from measured enclosure vibrational velocity, was related to radiated sound power due to rigid body loudspeaker cone vibration. Some of the enclosures exhibited certain structural modes which, through these studies, were identified as efficient sound radiators, and as such, candidates for further study in order to limit their radiated output.