Patent ID: 8130994

Claim:
A waveguide for mounting in a loudspeaker system comprising: an outer surface shaped to direct sound waves radiated from a first sound source positioned to generate the sound waves directed by the waveguide; an inner surface on a side opposite the outer surface; and a plurality of openings in the waveguide, each opening extending from the inner surface to the outer surface, the plurality of openings being disposed to overlay an acoustical radiating surface of a diaphragm of a second sound source mounted adjacent to the inner surface of the waveguide such that the inner surface of the waveguide covers the acoustical radiating surface of the diaphragm, the openings configured to enable the waveguide to function as an acoustical low pass filter for sound radiated through the openings from the second sound source where the function of the waveguide as the acoustical low pass filter depends on the distance between the diaphragm and the inner surface of the waveguide, the area between the openings creates a compression chamber between the inner surface of the waveguide and the acoustic radiating surface when the diaphragm of the second sound source vibrates, and a selected area of the openings, a ratio of area of the diaphragm to the area of the openings, and the distance between the diaphragm and the inner surface of the waveguide are selected by simulating operation of the second source using an equivalent electrical circuit model.