A Low-Diffraction Concentric Acoustic Combiner for Two-Way Loudspeakers

Abstract

A novel acoustic combiner for two-way loudspeakers uses an annular acoustic transmission line to couple woofer sound pressure to a tweeter waveguide, concentrically aligning high and low frequency sources without significant diffraction. Operating principles of the combiner are analyzed with an acoustic transfer-matrix model and finite element analysis. The combiner is implemented in a loudspeaker, and its nonlinear performance is compared with conventional two-way coincident coaxial and noncoincident loudspeakers. The combiner achieves a smooth directivity pattern in all off-axis planes and significantly lower levels of high frequency intermodulation distortion than the conventional coincident coaxial loudspeaker tested.