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.

Electroacoustical transducing with low frequency augmenting devices

A technique for enhancing audio signals generated from compressed digital audio files is described. The technique uses a Bass Maximizer module, a Harmonic Exciter module and a Quasi Stereo module. The Bass Exciter module enhances the intensity, depth and punch of the bass audio content by creating harmonic sequences from low frequency components contained in the original input signal. The Harmonic Exciter module adds to the treble audio content of the original input signal by generating harmonic series from the high frequency components contained in the input signal. The Quasi Stereo Module creates a stereo image of the enhanced input signal by adding and subtracting delayed and filtered versions of the enhanced input signal with itself to create left and right channeled stereo-like outputs. The technique provides a useful tool to regenerate from an audio signal more pleasant and joyful sounds.

Method and system for enhancing audio signals

An optical system for illumination is divided into a first
optical system (10A) and a second optical system (10B). The
second optical system (10B) is fixed to an exposure apparatus
main body (SP). The exposure apparatus main body (SP) is
provided to a base frame (41) via hard rubbers (31A and 32B)
and piezo actuators (32A and 32B), and isolates vibration from
the surface of the floor. The first optical system (10A) is
supported separately from the exposure apparatus (SP) via
actuators such as air mounts (14A and 14B) and voice coil motors
(VCMs) (12A, 12B, 13A, and 13B) etc. A control system (50)
compensates for the relative positional deviation between the
first optical system (10A) and the second optical system (10B)
detected by displacement sensors (26A and 26B) by controlling
the position of the first optical system (10A) by driving the
above described actuators.

Projection exposure apparatus

A method and a system for loudness calibration of a multichannel sound systems, wherein the test signal is psychoacoustically shaped. The psychoacoustically shaped test signal is preferably a pseudorandom test signal suitable for both automatic and subjective loudness calibration. Further, the psychoacoustically shaped test signal preferably has essentially constant specific loudness on the frequency range essential for aural perception.

Method for loudness calibration of a multichannel sound systems and a multichannel sound system

A system and a method for correcting, simultaneously at multiple-listener positions, distortions introduced by the acoustical characteristics includes intelligently weighing the room acoustical responses to form a room acoustical correction filter.

System and method for automatic room acoustic correction in multi-channel audio environments

A circuit for improving the transient behavior of a two-way loudspeaker system includes a crossover circuit with high selectivity, amplitude and phase correction circuitry for separately correcting the amplitude and phase responses of the high and low frequency drivers in their mounting environment, and correction circuitry for correcting the composite amplitude and phase response of the overall loudspeaker system after insertion of the crossover. A further phase offset technique and circuit provides for introducing frequency dependent phase shift in the loudspeaker system's high or low frequency channels for offsetting the phase responses of the high and low frequency drivers within the crossover frequency range. According to the phase offset technique of the invention, phase shift is added, preferably in the high frequency channel, until composite amplitude response curves observed on-axis and at different vertical angles off-axis are forced to be consistent. After consistency is achieved the deterioration of the amplitude response resulting from the phase offset is corrected to a flat response by means of a forced series amplitude correction circuit inserted before the crossover. The result is improved transient response off-axis as well as on-axis.

Correction circuit and method for improving the transient behavior of a two-way loudspeaker system

A manifold for a horn loudspeaker has an input end having at least one input port for receiving acoustic power from at least one acoustic driver, and an output end for delivering acoustic power to the throat end of the horn. The output end of the manifold has at least two and suitably multiple output ports. An acoustic power waveguide is provided for each output port and connects each of the output ports to the input port of the manifold. Acoustic power received by the input port is divided between the acoustic waveguides such that it is delivered to the aligned output ports to simulate a line array of acoustic power sources.

Manifold for a horn loudspeaker and method

An acoustical horn speaker for producing low distortion sound comprised of a casing assembly having a voice coil gap and a magnetic source and return circuit for providing a constant magnetic field across the gap, a current-carrying voice coil disposed in said gap, and a voice diaphragm in rigid attachment with the voice coil, said voice diaphragm being suspended from the casing assembly by a relatively flexible, high compliance suspension member. An acoustical horn having a throat resistance sufficiently high to substantially dominate the radiation resistance of the diaphragm is air coupled at its throat end to the voice diaphragm suspended from said casing, while the compliance of the voice diaphragm suspension is relatively high such that in the presence of the dominating throat resistance of the horn the diaphragm vibratory movement is characterized by substantially force determinative excursions as opposed to substantially linear constant displacement excursions. A method of producing low distortion sound in a horn type speaker comprising the step of driving the speaker's diaphragm in a vibratory movement characterized by substantially force determinative excursions as opposed to substantially linear constant displacement excursions.

Horn speaker and method for producing low distortion sound

A loudspeaker is provided that passively achieves a directional polar response at low frequencies with a high degree of attenuation between the front and the back of the loudspeaker. The loudspeaker 11 has a transducer 13, an enclosure 21 behind the transducer, and port openings 29 in the sidewalls 23 of the enclosure to allow a back- wave produced by the transducer to exit the enclosure and combine with the front wave produced by the transducer. Cancellation behind the loudspeaker at low frequencies is achieved by delaying the back wave with low loss. Low loss delay at low frequencies is achieved by inserting a low-density fibrous fill material 33 in the acoustic chamber 27 formed behind the transducer 13 by the enclosure 21. A fibrous material is selected having a low-pass transfer function and low acoustic loss in its low- frequency pass band.

Loudspeaker with passive low frequency directional control

A loudspeaker horn ( 11 ) having a throat end ( 13 ) for receiving acoustic power from aligned acoustic power sources ( 41, 43, 45 ), an elongated throat ( 33 ), and a flared section ( 17 ) is provided with grating lobe mitigation fins ( 27, 29 ) that extend substantially parallel to the propagation axis of the horn from the throat end toward the mouth end of the horn's flared section. The length of the grating lobe mitigation fins is established in accordance with the degree of suppression of the grating lobes produced by the aligned acoustic power sources that is desired.

John D. Meyer

Papers

Correction circuit and method for improving the transient behavior of a two-way loudspeaker system

Manifold for a horn loudspeaker and method

Horn speaker and method for producing low distortion sound

Loudspeaker with passive low frequency directional control

Loudspeaker horn and method for controlling grating lobes in a line array of acoustic sources