Abstract: An audio system (100) is provided with improved adaptive filter (206) to automatically adjust signal gain depending on the ambient noise level. The original music signal passes through a normalized adaptive filter (206), and is subtracted from the ambient room signal detected by a microphone (120), resulting in an error signal that is an estimate of the ambient noise. The error signal is used to update a set of adaptation coefficients so that the normalized adaptive filter more accurately simulates the room transfer function, resulting in an better estimate of the ambient noise. The audio system (100) is calibrated automatically upon initial use to determine adaptation coefficients and noise threshold level to prevent runaway gain. System parameters are adjusted using a controller (124) with a user-friendly interface (400).

Abstract: A low frequency horn apparatus including a throat (20), barrel (30) and mouth (40). The barrel (30) includes a series of chambers (50 and 60) wherein the cross-sectional area of each chamber in the series increases linearly from one end of the chamber to the other. The rate of linear increase is greatest in the first chamber 50 in the series. The chambers are in communication with one another so that sound waves entering the throat aperture (20) of the first chamber (50) in the series travel though each chamber in the series and exit the series of chambers through the mouth (40) of the last chamber (60) in the series. Sounds waves may be created by an electroacoustic transducer (70) that includes a cone. Further, the cross-sectional area of the mouth (40) may be less than the cross-sectional area of the cone (78).

Abstract: An electronics/heat sink housing used in combination with a loudspeaker or powered speaker having an enclosure, a passive radiator, and an electronics package. The electronics/heat sink housing includes a planar back plate, a top plate, two side plates, and a bottom connector plate. The housing is mounted directly onto a rear panel of the speaker enclosure over the electronics package and passive radiator of the speaker. A plurality of slots are formed within the electronics/heat sink housing, preferably along the side plates and top plate of the housing, where they are bent relative to the back plate. A plurality of larger slots also may be formed along the side plates of the housing. The total area of these slots is greater than the area of the passive radiator, so that the enclosure does not interfere with air movement and sound pressure wave propagation from the passive radiator. Air movement caused by the passive radiator serves to enhance the thermal cooling of the electronic components.

Abstract: A passive radiator assembly for a speaker that substantially reduces diaphragm resonance in the operating frequency range of the device. The new passive radiator assembly includes a quasi-elliptical shaped laminated honeycomb diaphragm, which is damped by an integral outer compliance (suspension) made of an elastomeric material that covers the entire upper surface of the diaphragm. The integrated outer compliance is of a progressive type, having a stiffness that increases in a controlled fashion during large excursions. To prevent non-linear rocking movements and compensate for displacement non-linearities, at least one, and preferably two, opposed spiders supported by a spider assembly frame are used to provide a restoring force applied to the diaphragm.