Abstract: A method and apparatus for creating a third signal channel from an input signal received in each of a first and second channel involves inverting a predetermined frequency range of signals in the first channel out of phase with a corresponding frequency range of signals in the second channel. Thereafter, the inverted signal in the first channel and the corresponding frequency signal in the second channel may be communicated to a speaker, which is bridged across the first and second channels, as the third signal channel. This speaker produces sound corresponding to the difference (i.e., the frequency range determined by the predetermined bandwidth of the inverted signal) between the inverted signal in the first channel and the corresponding frequency signal in the second channel.

Abstract: A method and apparatus for creating a third signal channel from an input signal received in each of a first and second channel involves inverting a predetermined frequency range of signals in the first channel out of phase with a corresponding frequency range of signals in the second channel. Thereafter, the inverted signal in the first channel and the corresponding frequency signal in the second channel may be communicated to a speaker, which is bridged across the first and second channels, as the third signal channel. This speaker produces sound corresponding to the difference (i.e., the frequency range determined by the predetermined bandwidth of the inverted signal) between the inverted signal in the first channel and the corresponding frequency signal in the second channel.

Abstract: A method and apparatus for creating a third signal channel from an input signal received in each of a first and second channel involves inverting a predetermined frequency range of signals in the first channel out of phase with a corresponding frequency range of signals in the second channel. Thereafter, the inverted signal in the first channel and the corresponding frequency signal in the second channel may be communicated to a speaker, which is bridged across the first and second channels, as the third signal channel. This speaker produces sound corresponding to the difference (i.e., the frequency range determined by the predetermined bandwidth of the inverted signal) between the inverted signal in the first channel and the corresponding frequency signal in the second channel.

Abstract: Differential flow vents allow airflow within a vent to be preferential. A flange disposed within a vent introduces non-linearities and causes a preferred direction of airflow into an expanding volume. The differential flow vents are used in conjunction with the natural motion of the loudspeaker cone acting as a pump to cool the loudspeaker cabinet enclosure without having to directly cool the woofer magnet structure. In one embodiment, at least one pair of opposed differential flow vents within the cabinet enclosure provide fresh air to be preferentially circulated to cool the interior of a loudspeaker system. In another embodiment, by providing an odd number of opposed differential flow vents within the cabinet enclosure, positive air circulation also results. By making either the pairs or odd number of differential flow vents to be asymmetrical, dynamic woofer offset is compensated.

Abstract: An augmentation amplifier includes a first power amplifier stage having an output adapted to be coupled to one side of a load. A second amplifier of negative unity gain has an output coupled to the input adapted to be of the first amplifier and its input coupled to the other side of the load. The circuit may be switched to bypass the bridge and modular units may be employed together. The system is particularly adapted for a powered speaker system for use with a computer sound card.

Abstract: A record handling device is disclosed which includes a frame which defines a handle and an arcuate record contacting member. This contacting member defines an arcuate groove sized to receive the peripheral edge of a record. A record retaining member is pivotably mounted to the frame so as to move between an open position, in which a record can freely be inserted in or removed from the groove, and a closed position, in which the record is captured in the groove. The record gripping device of this invention allows a record such as a phonographic record to be handled and transported safely and securely, without damage to the delicate recording surface. In addition, an album opening device is disclosed which comprises a groove defined by two sloping sidewalls and a base, and a blade situated within the groove.