Abstract: A direct field acoustic testing system comprising a control microphone, a controller operatively coupled to the control microphone such that the controller receives at least one input signal from the control microphone, and a plurality of acoustic transducer groups receiving an electronic signal from the controller, each transducer group including at least one acoustic transducer. An average power density of the direct field acoustic testing system for a pre-determined acoustic test spectrum being equal to or greater than 46 acoustic watts per square meter of total active acoustic transducer radiating surface area.

Abstract: A compact audio reproduction system for two input signals includes at least four loudspeakers disposed at the vertices of a quadrilateral not more than two feet on any side and such that no two loudspeakers are located at a distance from one another which is less than one-fourth the greatest distance between any two loudspeakers. The two input signals are connected to alternate speakers such that no two loudspeakers at adjacent vertices of the quadrilateral produce the same signal such that a listener at an arbitrary location perceives a sound source larger than the quadrilateral and significant stereo image. The signals received by two loudspeakers located at adjacent vertices may receive signals which are equalized separately from the signals received by the other loudspeakers for the purpose of reducing comb filtering and improving the tolerance of the device to placement near walls and other obstructions.

Abstract: In a loudspeaker system with main and sub-speakers, a modified and inverted left surround signal is added to the signals driving the right main speaker and a modified and inverted right surround signal is added to the signals driving the Left Main Speaker for the purpose of creating more credible rear located phantom sound images. In a system using variations of a difference signal to create phantom rear located sound images, the components of the difference signal are modified by introducing a time delay to one of the components for the purpose of preventing the components of the difference signal from substantially canceling each other. The components of the difference signal may be modified by altering the relative level and frequency response of the components for the purpose of preventing the components of the difference signal from substantially canceling each other.

Abstract: A loudspeaker system includes a cabinet with an interior air volume, a transducer, a first port extending from an opening in the front wall of the cabinet to the interior of the cabinet, and a second port extending from and opening in the rear wall of the cabinet to the interior of the cabinet. The first and second ports are aligned along a common longitudinal axis and the interior ends of the ports are separated from each other by a predetermined distance. First and second flanges having a diameter larger than the first and second ports are disposed at the interior ends of the first and second ports, respectively.

Abstract: A port for a loudspeaker is disclosed which is sufficiently weather resistant for long term outdoor use and which prevents debris, insects and other vermin from entering the loudspeaker and which is compact and efficient.

Abstract: A surround sound reproduction system uses a series of filters and a system of main and sub-speakers to produce phantom rear surround sound channels or a phantom surround sound effect from a loudspeaker system or pair of loudspeaker systems located in front of the listener. The sound system includes left and right surround input signals, and left and right front input signals. Left and right sub-speakers, and left and right main speakers are located in front of a listening location. Spacing between respective main and sub-speakers is approximately equal to ear spacing for an average person. The input to the left sub-speaker comprises the right surround signal subtracted from the left surround signal each signal having previously passed through a front-to-back filter and a series of high and low pass filters. The input into the left main speaker comprises the left front signal added to the left surround signal after the left surround signal has passed through a front-to-back filter.

Abstract: A mounting system for loudspeakers is provided. In general, the system comprises a flexible arm having a first end and a second end. The first end of the flexible arm is suitably mounted to the loudspeaker. The second end of the flexible arm is suitably mounted to a surface. The surface may comprise a wall, another loudspeaker and/or a computer monitor. Various combinations and arrangements of speakers are disclosed, including mounting systems advantageously configured to provide surround sound experiences.

Abstract: A loudspeaker-cable interface for use in audio reproduction systems including a capacitor and resistor for effectively terminating the cable with a predetermined impedance at frequencies above the audio range. The interface operates to inhibit generation of spurious high-frequency oscillations which could cause damage to the amplifier.