Abstract: An automated process for equalizing an audio system and an apparatus for implementing the process. An audio system includes a microphone unit, for receiving the sound waves radiated from a plurality of speakers, acoustic measuring circuitry, for calculating frequency response measurements; a memory, for storing characteristic data of the loudspeaker units and further for storing the frequency response measurements; and equalization calculation circuitry, for calculating an equalization pattern responsive to the digital data and responsive to the characteristic data of the plurality of loudspeaker units. Also described is an automated equalizing system including a acoustic measuring circuitry including a microphone for measuring frequency response at a plurality of locations; a memory, for storing the frequency responses at the plurality of locations; and equalization calculation circuitry, for calculating, from the frequency responses, an optimized equalization pattern.

Abstract: An automated process for equalizing an audio system and an apparatus for implementing the process. An audio system includes a microphone unit, for receiving the sound waves radiated from a plurality of speakers, acoustic measuring circuitry, for providing frequency response measurement signals; a memory, for storing characteristic data signals representative of the loudspeaker units and further for storing the frequency response measurement signals; and equalization calculation circuitry, for providing an equalization pattern signal responsive to the frequency response measurement signals and responsive to the characteristic data signals representative of the plurality of loudspeaker units.

Abstract: Electroacoustical apparatus includes according to one aspect structure for providing a sound field concentrated at a restricted listening region corresponding substantially to a human head while being spaced from the restricted listening region. According to another aspect an electroacoustical transducer is located at the interface of an acoustic waveguide and a ported enclosure.

Abstract: Noise attenuation apparatus comprising an enclosure having a wall separating an interior and an exterior. The enclosure defines a volume. The volume is characterized by an acoustic compliance and includes a device producing noise. The noise has spectral components predominantly in a noise frequency range. A first port has a first acoustic mass. The port passes through the wall between the interior and the exterior wherein the acoustic compliance and the first acoustic mass are configured to establish a resonant frequency outside the noise frequency range.

Abstract: A system for controlling the flow of fluid through a line 3. The system may include first and second valves (A, B; and 6, 7) in the line 3 between is located a chamber (52, 82), part of which may be filled with fluid having a variable volume (52), and another part is filled with a measurement gas (V.sub.1), such as air. The chamber may be isolated from the pressure effects in the rest of the line by closing both valves. The valves may also permit fluid to flow into or out of the chamber. The second portion of the chamber has a common boundary with the first part in such a way that the combined volume of the first and second parts is constant. A loudspeaker (22, 33, 571) creates sound waves in the gas in the second part of the chamber, in order to measure the volume of the fluid in the first part, and for directing the operation of the valves and creating subsonic pressure variations to produce the desired flow. The volume measurement is achieved by acoustic volume measurement techniques.

Abstract: A system for controlling the flow of fluid through a line 3. The system may include first and second valves (A, B; and 6, 7) in the line 3 between is located a chamber (52, 82), part of which may be filled with fluid having a variable volume (52), and another part is filled with a measurement gas (V.sub.1), such as air. The chamber may be isolated from the pressure effects in the rest of the line by closing both valves. The valves may also permit fluid to flow into or out of the chamber. The second portion of the chamber has a common boundary with the first part in such a way that the combined volume of the first and second parts is constant. A loudspeaker (22, 33, 571) creates sound waves in the gas in the second part of the chamber, in order to measure the volume of the fluid in the first part, and for directing the operation of the valves and creating subsonic pressure variations to produce the desired flow. The volume measurement is achieved by acoustic volume measurement techniques.

Abstract: A system for controlling the flow of fluid through a line 3. The system may include first and second valves (A, B; and 6, 7) in the line 3 between is located a chamber (52, 82), part of which may be filled with fluid having a variable volume (52), and another part is filled with a measurement gas (V.sub.1), such as air. The chamber may be isolated from the pressure effects in the rest of the line by closing both valves. The valves may also permit fluid to flow into or out of the chamber. The second portion of the chamber has a common boundary with the first part in such a way that the combined volume of the first and second parts is constant. A loudspeaker (22, 33, 571) creates sound waves in the gas in the second part of the chamber, in order to measure the volume of the fluid in the first part, and for directing the operation of the valves and creating subsonic pressure variations to produce the desired flow. The volume measurement is achieved by acoustic volume measurement techniques.

Abstract: A system for controlling the flow of fluid through a line (3). The system may include first and second valves (A, B; and 6, 7) in the line (3). Between the first and second valves is located a chamber (52, 82), part of which may be filled with fluid having a variable volume (52), and another part of which is filled with a measurement gas (82, V.sub.1), such as air. The chamber may be isolated from the pressure effects in the rest of the line by closing both valves. The valves may also permit fluid to flow into or out of the chamber. The second portion of the chamber has a common boundary with the first part in such a way that the combined volume of the first and second parts is constant. A loudspeaker (22, 33, 571) creates sound waves in the gas in the second part of the chamber, in order to measure the volume of the fluid in the first part.

Abstract: A sound system has at least two loudspeaker drivers and associated amplifiers and operate over frequency ranges at least part of which are in common. Non-minimum phase circuitry modifies the signal applied to at least one of the loudspeaker drivers to provide a frequency response at a desired listening position that is more uniform.