Abstract: A method for processing a multichannel audio signal. The method includes mounting electroacoustical transducers in a low frequency augmenting device. The electroacoustical transducers radiate different high frequency acoustic energy and common low frequency acoustic energy. The transducers may be part of directional arrays. The method is applied to multimedia entertainment devices.

Abstract: A multichannel audio system for radiating sound to a listening area that includes a plurality of listening spaces. The audio system includes directional audio devices, positioned in a first of the listening spaces, close to a head of a listener, for radiating first sound waves corresponding to components of one of the channels and nondirectional audio devices, positioned inside the listening area and outside the listening space, distant from the listening space, for radiating sound waves corresponding to components of a second of the channels.

Abstract: A method of down mixing a plurality of signals including at least a left surround signal, a right surround signal, a left signal and a right signal into a stereophonic pair that is a left transmitted signal and a right transmitted signal includes summing the left surround and right surround signals to provide a monophonic surround signal, filtering the monophonic surround signal to provide a filtered monophonic signal having properties related to the diffraction pattern around the head of a listener, multiplying the filtered monophonic surround signal with a right coefficient signal related to the ratio of the magnitude of the right surround signal to the sum of the magnitudes of the left surround signal and the right surround signal to provide a left product signal and multiplying the filtered monophonic surround signal with a left coefficient signal related to the ratio of the magnitude of the left surround signal to the sum of the magnitudes of the left surround signal and the right surround signal to prov

Abstract: Surround sound encoding and decoding includes apparatus and techniques for encoding a number of major channels of a surround sound signal, such as left, right, center, left surround and right surround, into a lesser number of channels, such as left transmitted and right transmitted, and decoding the lesser number of channels into a larger number of decoded channels, such as left, right, center, left surround and right surround, for being electroacoustically transduced.

Abstract: A method for processing and transducing audio signals. An audio system has a first audio signal and a second audio signal that have amplitudes. A method for processing the audio signals includes dividing the first audio signal into a first spectral band signal and a second spectral band signal; scaling the first spectral band signal by a first scaling factor proportional to the amplitude of the second audio signal; and scaling the first spectral band signal by a second scaling factor to create a second signal portion. Other portions of the disclosure include application of the signal processing method to multichannel audio systems, and to audio systems having different combinations of directional loudspeakers, full range loudspeakers, and limited range loudspeakers.

Abstract: An acoustic waveguide system, having source of acoustic radiation and a source of opposing acoustic radiation. An acoustic waveguide has an open end and an interior. A first acoustic driver having a first radiating surface and a second radiating surface is arranged and constructed so that the first radiating surface radiates sound waves into free air and the second radiating surface radiates sound waves into the acoustic waveguide so that sound waves are radiated at the open end. A source of opposing sound waves in the acoustic waveguide opposes a predetermined spectral component of the sound waves radiated into the acoustic waveguide to reduce the acoustic radiation of the predetermined spectral component from the acoustic waveguide.

Abstract: Combining audio channel signals includes shifting the phase of a first audio signal relative to a second audio signal. In one embodiment, the relative phase shifting is substantially limited to a predetermined frequency range.

Abstract: A system for extracting a bass signal from left and right audio input signals of a stereo signal including a differencing circuit generating a difference mode signal from the left and right audio input signals; a detector circuit generating a first coefficient of proportionality that is a function of the relative phase of the left and right input signals; and a first multiplier circuit multiplying the first coefficient of proportionality times the difference mode signal to produce a modified difference mode signal, wherein the modified difference mode signal is used to generate the bass signal.

Abstract: Electroacoustical transducing apparatus includes an input for receiving an audio electrical signal. A first electroacoustical transducer is constructed and arranged to radiate first sound waves in a first direction in a first frequency range in response to an audio electrical signal on the input. A second electroacoustical transducer is constructed and arranged to radiate sound energy in a second direction in a second frequency range. A third electroacoustical transducer is constructed and arranged to radiate sound energy in a third direction within the second frequency range.

Abstract: A stereo audio system includes a plurality of drivers and a signal processor circuit. The signal processing circuit has at least a left channel input and a right channel input, and provides at least one processed signal on at least one output. The processed signal is characterized by a coefficient of proportionality representative of complex components of the signals on the left channel input and the right channel input. The coefficient of proportionality is at a maximum and minimum for the complex components on the left channel input and the right channel input being in phase opposition and phase coherence, respectively. Each of the signals on the left channel input, the right channel input, and the at least one output are received by at least one of the drivers, and each of the drivers receives at least one of the left channel input signal, the right channel input signal, and the processed signal.

Abstract: An acoustic imaging device includes a support structure and first and second drivers mounted on first and second faces respectively of the support structure. The first driver projects sound output in a first direction, and the second driver projects sound output in a second direction. The sound output of the second driver is out of phase with sound output of the first driver, and is at a level calculated to reduce substantially sound output from the first driver in a direction other than the first direction.

Abstract: A circuit controls the sound pressure level produced by a separate bass transducer in a multi-channel audio system having a number of upper frequency channels such that the perceived frequency response of the system remains substantially constant.