Abstract: A vented or bass reflex speaker. The speaker is secured to an inner sleeve which inner sleeve is received within an outer sleeve with the sleeves defining an annulus therebetween. Acoustical flow channels are formed in the annulus. The back of the inner sleeve is spaced apart from the back of the outer sleeve to form a vented volume. The air in the channels is caused, by the loudspeaker driver, to resonate with the volume of air contained within the open-ended inner sleeve forming a Helmholtz element.

Abstract: An assembly for mounting loudspeakers in a panel. A hole is formed in the panel. An outer ring having a flange is secured in the hole with the flange on one side of the panel. An inner resilient ring is collapsed, passed through the outer ring to the other side of the panel, expanded and secured to the outer ring. This locks the rings together. A loudspeaker is secured in the flange.

Abstract: A system for low frequency sound production in vehicular passenger compartments, comprising an electrodynamic driver, having a first acoustic mass and a first acoustic compliance; and a Helmhotz resonator, affixed to one side of said electrodynamic driver means and having a second acoustic mass and a second acoustic compliance, the second acoustic mass being affixed to a baffle facing the passenger compartment. The first and second acoustic mass have substantially similar magnitudes, and the Helmholtz resonator and the electrodynamic driver being substantially tuned to the highest and lowest frequencies of a desired passband, respectively, so as to provide a substantially flat pressure vas. frequency characteristic when the passenger compartment has dimensions generally smaller than one eighth wavelength of the lowest frequency.

Abstract: A loudspeaker cabinet which is formulated from a nonfoamed, molded, filled polymer having between 20-90% inert filler and a density of between 1.0-6.0 gm/cm.sup.3. Preferably the polymer is a polyester.

Abstract: A loudspeaker has a focused magnetic field and a specialized voice-coil structure, which provides constant inductance at the voice coil over the entire extent of voice coil excursion. The magnetic field is focused to a thin disc and the winding of the voice coil is of a height so that it is always in view of the thin disc of the magnetic field. The voice coil winding is not more than two layers. An extended base cross-section center pole is employed having an undercut portion forming a crown at the top. The edges of the crown are chamfered to cooperate with chamfered edges on a top plate to form the thin disc of the focused magnetic field.

Abstract: A loudspeaker enclosure is shaped as a truncated pyramid with all vertical edges being smoothly rounded. A high-frequency speaker is mounted in an individual spherical shell and affixed to the top of the truncated pyramid. Other speakers are mounted inside the enclosure, and the portion of enclosure adjacent the speaker in a horizontal plane is kept to a minimum to reduce standing waves. An individual sound chamber is provided for each speaker mounted inside the enclosure. The speakers are also mounted with vibration isolation mounts which vibrationally decouple the speakers from the enclosure.