Abstract: A surround sound apparatus wherein a decoder decodes directionally encoded audio signals for reproduction via a loudspeaker layout over a listening area wherein the signals are decoded by a matrix. The coefficients of the decoding matrix are such that at a predetermined listening position, the reproduced velocity vector direction and the reproduced energy vector position directions are substantially equal to each other and substantially independent of frequency in a broad audio frequency range The gain coefficients of the decoding matrix are such that the reproduced velocity vector magnitude varies systematically with encoded sound direction at frequencies in the region of and above a predetermined middle audio frequency.

Abstract: Digital sound data are stored in a data memory. When a first display object (such as an enemy character, a waterfall, or the like) is displayed in a three-dimensional manner on a display screen, an audio processor reads out corresponding sound source data from the data memory to produce first and second sound source data. The first and second sound source data are converted into analog audio signals by digital-to-analog converters, and then used to drive left and right speakers. The audio processor calculates a delay between generation of the first and second sound source data based on a direction of the first display object as viewed from a "virtual" camera which might correspond for example to one of the graphical characters in the three-dimensional display. The audio processor also controls sound volume levels for the first and second sound source data depending on the distance between the first display object and the virtual camera.

Abstract: A system for controlling distribution of sound in a multi-channel sound system such as a "surround sound" system in a movie theater. Control signals are used to steer, or distribute, portions of the sound signal between designated speakers. In a preferred embodiment the control signals are provided with the sound signals, themselves, and are separated from the sound signals by using a pilot signal or signals.

Abstract: A signal combining circuit has a first input and a second input for receiving signals which have frequencies in the audio frequency spectrum, and an output. A first signal path between the first input and the output has a first transfer characteristic (H1.H3). A second signal path between the second input and the output has a second transfer characteristic (H2.H3). The transfer characteristics are different which causes a phase shift to occur between signal components passed through the first signal path and signal components passed through the second signal path. The amplitude transfer determined by the transfer characteristics decreases above a predetermined frequency. There is a phase difference between phase transfer characteristics which decreases with frequency. For frequencies below the predetermined frequency the amplitude transfer determined by the first transfer characteristic exceeds that determined by the second transfer characteristic.

Abstract: A surround sound converter for home audio systems includes outputs for a left front speaker, a right front speaker, a left rear speaker, a right rear speaker, and an auxiliary output to accommodate a rear auxiliary amplifier. The surround sound converter also includes an input for the left and right channel speaker output of an amplifier, a receiver, or any stereo signal device which has an audio amplifier. At least one potentiometer controls the volume balance between the front and rear speakers. A left and right capacitor are used to drive the left and right rear speakers, respectively. An auxiliary output is provided to accommodate adding a rear auxiliary amplifier. A surround sound converter for vehicle audio systems utilizes an automotive stereo. A left front speaker and right front speaker are connected to the normal speaker outputs of the automotive stereo. The left rear speaker is connected to the left rear signal negative and the right rear signal negative.

Abstract: A surround sound processor unit includes a plurality of preamplifiers, an in-phase audio decoder circuit, an out-of-phase audio decoder circuit, at least one transmitter, at least one receiver, at least one speaker amplifier, and a plurality of power amplifiers. A surround sound processor unit can take the stereo audio signal from a stereo VCR, a stereo receiver, a headphone jack, a stereo TV, or a car stereo to produce a three dimensional sound field. The left audio signal is amplified and outputed to a left front speaker. The right audio signal is amplified and outputed to a right front speaker. The in-phase audio decoding is accomplished by preamplifying the left and right audio signal, and connecting the output of the left and right preamplifiers to a singular input of a power amplifier. The output of the power amplifier drives a center channel speaker.

Abstract: An image communication apparatus such as a facsimile apparatus has: a receiving device for receiving coded data, a decoder for decoding the coded data received by the receiving device and for conducting an operation for detecting a transmission error in each of plural data lines based on the decoded data; a controller for controlling the operation of the decoder and for generating data to be recorded by conducting decoding of the coded data while removing the coded data of the lines in which a transmission error has been detected; and a recording device for recording an image on a recording sheet in accordance with the data decoded by the controller. The decoding and transmission error detection operation performed by the decoder are conducted in parallel with the decoding operation performed by the controller. The control means operates to cause the decoder to execute its own decoding operation preferentially to the decoding operation for generating the data to be recorded.

Abstract: A sound field control device includes a surround decoder for decoding an input surround encode signal and generating three channel signals of L, C and R to be reproduced in front left, front center and front right and one channel signal of S to be reproduced in the rear, output terminals for outputting the three channel signals, a first reflected sound generation section generating a reflected sound of the signal S, a second reflected sound generation section generating another reflected sound signal of the signal S, a first adder adding the reflected sound signal generated by the first reflected sound generation section and the signal S together, a phase shifting section shifting phase of the reflected sound signal generated by the second reflected sound generation section according to frequency of the reflected sound signal, a second adder adding a reflected sound signal provided by the phase shifting section and the signal S together, and output terminals for outputting signals of RL and RR channels for re

Abstract: An improved theater surround sound system incorporates a screen top speaker and an overhead speaker driven by corresponding upper surround channels to more accurately reproduce sounds produced from above the listener. These top surround channels are encoded along with the left and right surround channels. A pilot signal is used to direct the sound from the side surround channels to the upper surround channels when needed.

Abstract: A surround sound processor system includes an in-phase decoder circuit, an out-of-phase decoder circuit, and a plurality of audio amplifiers. In a wireless embodiment, the surround sound processor system also includes a plurality of FM transmitters and a plurality of FM receivers. A surround sound process system can take the stereo audio signal from a stereo VCR, a stereo receiver, a car stereo, or a stereo TV to produce a three dimensional sound field. A left audio signal and a right audio signal are input into an in-phase decoder, the in-phase audio signals are extracted from the left and right audio signals while the out-of-phase audio signals are canceled. The in-phase audio signals are sent to an audio amplifier and then to at least one center speaker. A left audio signal and a right audio signal are input into an out-of-phase decoder, the out-of-phase audio signals are extracted from the left and right audio signals while the in-phase audio signals are canceled.

Abstract: An apparatus for realistically reproducing sound, particularly for sound based on a stereophonic signal having dialog and effects and associated with an accompanying video image. The apparatus includes a front speaker located in proximity to the video image for providing acoustic output based upon a summation signal of the component left and right (L+R) channels of the audio signal. A rear speaker located to the rear of the viewing area provides acoustic output based upon a difference signal, (L-R) or (R-L), between the left and right channels. Left and right speakers located to the respective left and right sides of the viewing area output audio based upon the respective left or right channels. The left and right channels speakers reproduce in one embodiment the respective left and right channels of the audio signal and in a second embodiment reproduce a difference signal, (L-R) or (R-L).

Abstract: A multichannel sound reproduction method and apparatus are described for achieving a higher proportion in the overall room size for acoustic/visual use, which can be used for the listening-position-independent reproduction of spatial information in maintaining the given directional information of the individual sound signal sources. In the described method, each signal is split up and, after a summation, part of it with an increased delay, a modified level and a changed phase position is supplied to one of the unchanged signal portions, with the aggregate signals being distributed and supplied to the two surround reproduction channels and to other reproduction loudspeakers distributedly located in the room in conformity with directional allocation and in accordance with the relevant unchanged signal portions.

Abstract: In a method of coding a plurality of audio signals, the left and the right basic channel as well as the central channel are combined by joint stereo coding so as to obtain a jointly coded signal, which is decoded so as to provide simulated decoded signals. The simulated decoded signals and two surround channels are combined by matricization by means of a compatibility matrix so as to form compatible signals which are suitable for decoding by existing decoders.

Abstract: A method and apparatus for dynamic, adaptive mapping of three-dimensional aural phenomenon to a two-dimensional sound reproducing surface. The surface is comprised of sound pixels that are discrete, addressable output locations. Actual or synthetic recorded audio material is decomposed into discrete sound sources which are then mapped to the sound pixels. This mapping occurs during the production phase by means of computer-aided design (CAD) system. The CAD system guides the sound designer in the implementation of complex acoustical designs by automating the most complex and computationally intensive functions. The mapping function can be extended to integrate real-time human interaction, ultimately creating a participatory, interactive virtual sound environment.

Abstract: An AC-3 decoder output signals of five channels, i.e., main signals of left front, center front and right front channels and surround signals of two channels. A first synthesizing section synthesizes the three-channel main signals and a difference signal between the two-channel surround signals, and the resultant synthesized signals are then fed to a main sound field signal forming section which in turn forms main sound field signals. A second synthesizing section synthesizes the surround signals of the two channels and a difference signal between the main signals of the left and right channels, and the resultant synthesized signals are fed to a surround sound field signal forming section which in turn forms surround sound field signals. A composite sound field forming section synthesizes the main sound field signals, surround sound field signals and original surround signals so as to form composite sound field signals.

Abstract: A circuit for use in connection with a stereo audio system to increase the ambience includes a differencing circuit for receiving a left stereo input and a right stereo input. The differencing circuit produces an output signal having a difference of the left stereo input and the right stereo input. A shelf filtering circuit is operably coupled to the differencing circuit to receive the output signal. The shelf filtering circuit has a first passband range of frequencies wherein the output signal is attenuated at a first level and a second passband range of frequencies wherein the output signal is attenuated at a second level. The shelf filtering circuit has a crossover frequency between the first passband range of frequencies and the second passband range of frequencies. A summing circuit operably coupled to the left input and the right input and operably coupled to the shelf filtering circuit receives an output signal from the shelf filtering circuit.

Abstract: A frequency-dependent linear audio signal processor takes source signals S in input signals and provide directionally spread directionally encoded output signals. The processor directionally encodes with constant gain magnitude frequency components of the source signal S to-and-fro across a predetermined directional stage P" as frequency increases such that at least three predetermined positions within the stage P", the directional encoding has substantially zero perceived phasiness. The processor may be a frequency-dependent rotation matrix for stereo input signal and may be a unitary network using a feedback path around parallel identical all-pass networks in series with a rotation matrix and a feedforward path bypassing the all-pass networks. Successive frequencies of positioning of source signal S at a predetermined position P within the stage P" are preferably spaced approximately uniformly on a logarithmic or Bark Frequency scale.

Abstract: A surround sound processor system for multichannel redistribution of stereophonic signals has digitally controlled gains in each input and each output channel, controlled by a microprocessor, which receives an input signal from a microphone placed at the preferred listening location within the listening area for automatically balancing the input signals and setting both input and output gains during a calibration process so as to provide the listener with the best possible surround sound reproduction of the stereophonic source material. As a visual aid, the microprocessor displays menus and messages on a video screen, and a visual display shows the relative levels of the six axes of control signals within the surround sound processor.

Abstract: A surround-sound system for use with conventional TV sets, using a wireless remote bipolar rear speaker (or two conventional speakers fed out of phase) for the surround (difference) channels. The use of the rear speaker(s) and the mono (left plus right) front speaker on the TV set creates "phantom" left and right front speakers, and allows full surround sound without modification to the TV set or additional amplifiers or speakers.

Abstract: A surround sound processor for presenting stereophonic audio signals on a number of loudspeakers surrounding a listening area, comprising an input matrix stage, a detector filter and matrix circuit, a direction detector circuit incorporating improved filters, a novel detector splitter circuit providing three direction signals from the two direction detector circuit outputs, a novel three-channel servologic circuit with improved variable filters responding selectively to the rates of change of the direction signals and providing six control voltage signals through linearity correction networks to six voltage-controlled amplifiers, the outputs of which are combined in an output matrix to provide a number of loudspeaker feed signals through buffer amplifiers to the output terminals of the processor. The detector splitter circuit is configurable to either a forward oriented or a backward oriented mode of operation, corresponding changes being made to the voltage-controlled amplifiers and output matrix circuitry.

Abstract: In order to require only a relatively small increase in the data rate when the number of channels of multi-channel digitalized and bit-rate reduced audio signals is increased, the psychoacoustic concealment or masking by at least part of the remaining audio channels or the redundancy of individual audio channels is taken advantage of in each individual audio channel when reducing the bit rate of audio signals having more than two audio channels. Only those parts of the concerned audio channel are transmitted or stored which are not concealed by the audio signals of other audio channels or which are contained in the audio channels for stereophonic reproduction with all types of reproduction available for selection. In addition, the used parts are transmitted or stored with a resolution only big enough for the totality of all audio channels to keep concealed the quantization noise generated during quantization in all types of reproduction available for selection.

Abstract: A stereo computer system with resources to produce and record surround sound channels. Such surround sound channels are played or recorded using an audio card added to the computer system, which audio card controls additional speakers and/or microphones. Software for redirecting instructions from existing stereo application programs and sending these instructions to the existing audio device driver and the additional audio device driver is provided. Resources for processing the digital audio data for either extracting surround sound channels from two channel data provided by the application, or for encoding two sets of two channel audio data recorded by the two audio cards is also included.

Abstract: A surround sound processor for redistribution of stereophonic audio signals into multiple channels for presentation on a plurality of loudspeakers surrounding a listener has an improved direction detector filter circuit, a peak hold circuit in the direction detector for better dynamic separation, improved time constants in the servologic circuit, improved linearity correction in the control voltage generator to match the characteristics of the new voltage controlled amplifiers which are applied to the separation matrix, a separation matrix having cancellation of unwanted signals wihtout gain modification for desired signal components, and improved shelf filters in the rear channel outputs.

Abstract: An audio-imaging system includes at least first and second input channels for receiving first and second channel audio input signals and at least first, second and third output signals which are produced as a combination of the first and second channel audio input signals and a nonzero parameter. The parameter is common to the first, second and third output signals and may be made adjustable in order to vary the width of the audio image produced in order to compensate for composition mixing of a program source applied to the input channels. A sound-image analyzer is also provided which processes a program source applied to the input channels to at least three fully separated levels representing left, right and center directions of the program source in order to determine a value of the parameter.

Abstract: The present invention relates to an audio signal processing apparatus and method, and more particularly to an apparatus and method for processing an audio signal according to surround modes in which a surround-sound of an original sound, in accordance with surround modes, can be reproduced by carrying surround code information with the audio signal being transmitted and by detecting the surround code information upon receipt of the audio signal.

Abstract: An improved theater surround sound system incorporates a screen top speaker and an overhead speaker driven by corresponding upper surround channels to more accurately reproduce sounds produced from above the listener. These top surround channels are encoded along with the left and right surround channels. A pilot signal is used to direct the sound from the side surround channels to the upper surround channels when needed.

Abstract: Matrix reproduction decoding means derive from input signals intended to feed a stereophonic plurality of loudspeakers output signals intended to feed a second greater plurality of loudspeakers in a stereophonic arrangement covering a sector of directions, substantially so as to preserve total reproduced energy to within an overall gain and equalization, and to preserve to within constants of proportionality the angular dispositions of reproduced acoustical velocity and sound intensity vectors at an ideal listening position. Preferably for two-channel signals matrix means is frequency-dependent giving increased angular width above 5 kHz, and may incorporate width control. Matrix means encoding loudspeaker feed signals into transmission channel signals, and matrix means decoding transmission channel signals into loudspeaker feed signals may be used giving overall matrix means in accordance with the invention.

Abstract: The invention introduces an arrangement which maintains the usefulness of a fader control (11) connected for example to an audio signal source (10), and at the same time considerably reduces the circuit cost. This is realized in that the distribution to different listening areas adjusted by the fader control (11) is determined from the audio signals that are present behind the fader control (11). To that end, first the audio output signals (L, R) are reconstructed in two adders (12.2, 12.3) and routed to a fourth adder (12.4). Two each audio signals (L.sub.V, R.sub.V) are routed to a first adder (12.1). The signals existing behind the adders (12.1/4) are then placed into a ratio with each other by a divider (20). From the quotient Q determined there, the distribution rate is then determined by a calculator (21) and made available to the multipliers (M1-4). Devices (17) to determine the average level value, followed by smoothing devices (18), which are positioned symmetrically with respect to the adders (12.

Abstract: A surround signal processing apparatus, by which an inputted rear surround signal can be reproduced, together with two-channel front stereophonic signals, through a pair of speakers arranged in front of and in substantially right-and-left symmetry about a listener, in such a way that two sound images of the reproduced rear surround signal can be localized at two predetermined positions relative to the listener. The inputted rear surround signal is processed by a filter. The signal processed by the filter is added to one of the stereophonic signals, and then outputted to one of the pair of speakers. Further, an inversion signal of the filter-processed signal is added to the other of the stereophonic signals, and then outputted to the other of the speakers.

Abstract: According the present invention, a sound field controller for reproducing a sound field with presence comprising; input terminals for inputting an audio signal having a first and a second channel signals, a signal extracting circuit for receiving and processing the audio signal, and producing an extracted signal of the audio signal, an operation circuit for receiving the extracted signal from the signal extracting circuit, performing the convolution on the extracted signal, and generating a convolution sum signal, a delay circuit for delaying the convolution sum signal by a predetermined time, and producing a delayed signal, an adding circuit for receiving the audio signal and the delayed signal, and adding the audio signal and the delayed signal with a predetermined summation ratio to produce a summed signal, and output terminals for reproducing the summed signal to localize a sound image in a desirable direction.

Abstract: An audio playback apparatus and method are disclosed which includes a Dolby pro-logic decoder for converting a digital audio signal into a left signal, a right signal, a center signal, and a surround signal; a sound field processor for converting the left, right, center and surround signals into a front left signal, a front right signal, a rear left signal, and a rear right signal; an audio processor for mixing the left, right, front left, front right, rear left and rear right signals according to a predetermined relationship equation and converting them into signals for two channels composed of a left-speaker output signal and a right-speaker output signal; and audio output means for outputting the left-speaker output signal via a left speaker, the right-speaker output signal via a right speaker, and the center signal via a central speaker, thereby allowing a listener to feel a rich sound presence even with fewer output speakers then with conventional audio playback apparatuses.

Abstract: A unified loudspeaker system and method for use with a home theater stereo surround sound receiver. A plurality of binaural (dual) loudspeakers are housed in a single loudspeaker enclosure having a multiply-segmented face portion. Left and right loudspeakers are canted away from a center loudspeaker to provide more complete audio coverage of a defined listening area with audio channel separation. Six (6) equalized soundfields generated via five (5) surround sound channels from the loudspeaker enclosure configuration provide arrival times of the soundfields according to that of a live performance. Conventional two-channel stereo input sources may be combined by the system to provide desired soundfields. The preferred embodiment for a full dimensional sound field system contemplates the use of a Dolby Pro Logic AC-3 five or six channel receiver or the like as an input source.

Abstract: In an MPEG multi-channel audio signal processor, a decoder requires a respective decoder matrix for determining different output channels from coded audio data. Some transmitted information indicates basic parameters of the multi-channel system. This information may be used to address a currently required decoder matrix which is stored in a decoder memory. The storage of a large number of such matrices would be required to enable the decoder to decode all possible channel configurations. Instead of addressing a required decoder matrix stored in decoder memory, initially the current encoder matrix is reconstructed in the decoder using the related transmitted information. The required decoder matrix is then computed from the reconstructed encoder matrix using a matrix inversion technique.

Abstract: A sound field control device for reproducing plural reflected sound signals of a source signal about a listening point includes a reflected sound signal generation section for generating reflected sound signals to be sounded at front left and front right positions of the listening point and a reflected sound signal to be sounded at a rear position of the listening point, a phase shifting circuit for phase shifting the reflected sound signal to be sounded at a rear position and thereby producing a first phase shifted signal and a second phase shifted signal which are different in phase substantially by 180 degrees from each other, a first adder for adding the reflected sound signal to be sounded at a front left position and the first phase shifted signal together, and a second adder for adding the reflected sound signal to be sounded at a front right position and the second phase shifted signal together.

Abstract: A method and apparatus for dynamic, adaptive mapping of three-dimensional aural phenomenon to a two-dimensional sound reproducing surface. The surface is comprised of sound pixels that are discrete, addressable output locations. Actual or synthetic recorded audio material is decomposed into discrete sound sources which are then mapped to the sound pixels. This mapping occurs during the production phase by means of computer-aided design (CAD) system. The CAD system guides the sound designer in the implementation of complex acoustical designs by automating the most complex and computationally intensive functions. The mapping function can be extended to integrate real-time human interaction, ultimately creating a participatory, interactive virtual sound environment.

Abstract: An encoding method and apparatus for audio signals for generating ten-channel audio signals from audio signals of a left channel, a left center channel, a center channel, a right center channel, a right channel, a surround left channel, a surround right channel and a sub-woofer channel, totalling at eight channels.

Abstract: A surround sound processor for presenting stereophonic audio signals on a number of loudspeakers surrounding a listening area, comprising an input matrix stage, a detector filter and matrix circuit, a direction detector circuit incorporating improved filters, a novel detector splitter circuit providing three direction signals from the two direction detector circuit outputs, a novel three-channel servologic circuit with improved variable filters responding selectively to the rates of change of the direction signals and providing six control voltage signals through linearity correction networks to six voltage-controlled amplifiers, the outputs of which are combined in an output matrix to provide a number of loudspeaker feed signals through buffer amplifiers to the output terminals of the processor. The detector splitter circuit is configurable to either a forward oriented a backward oriented mode of operation, corresponding changes being made to the voltage-controlled amplifiers and output matrix circuitry.

Abstract: A passive multi channel surround sound simulation device has a pair of input jacks for receiving a two channel stereophonic signal having a speaker level. An electronic circuit produces from the two channel signal left and right primary speaker level outputs, left and right secondary speaker level outputs, a mono center line level output, left and right secondary line level outputs, and a surround ground separate from an input ground. First, second and third voltage dividers reduce the stereophonic signal speaker level to a line level of about 10% of that which appears at the left and right primary speaker level outputs, for directing to the mono line level output, and the left and right secondary line level outputs respectively. The left and right primary speaker level outputs are connected to left and right front speakers respectively. The left and right secondary speaker level outputs are connected to left and right rear speakers respectively.

Abstract: A head mounted surround sound virtual positioning system that includes a video recorder (200), which is operable to have disposed therein a tape (202), having a surround sound audio track associated therewith. The surround sound system is encoded on two channels, which are output to a Dolby.RTM. decoder (204), which is operable to extract the five surround sound system channels therefrom. The left front, left rear, right front and right rear channels are input to a virtual positioning system (264), which is operable to virtually position each of the speakers relative to the head of the listener (26). These signals are then combined with a combining circuit (268) to provide the virtual positioning of only two speaker lines (58) and (60), disposed adjacent the right and left ears of the listener (26). The speakers (58) and (60) are disposed on the head mounted system such that they are fixed relative to the ear of the listener and slightly forward of the ears and adjacent the head.

Abstract: A surround sound processor for presentation of a stereophonic source program on a multiple loudspeaker array surrounding the listening area. The processor includes input signal conditioning and matrixing circuits, a control voltage generator responsive to the directional information contained in the stereophonic source signals, and a variable matrixing circuit for generating appropriate loudspeaker feed signals to create the illusion of the sound field wrapping around the listening area. The control voltage generator includes a servologic circuit employing variable time constant smoothing circuits each responsive to the difference signal between its input and its output and to a pulse signal from a one-shot triggered by threshold detectors which compare the difference signals with fixed threshold voltages. In one aspect, suitable for incorporation into an integrated circuit, a multiplier circuit and a controlled bidirectional current source charging and discharging a capacitor provides the smoothing function.

Abstract: An entertainment system for a vehicle having front and rear speakers includes a high quality entertainment system for playing a high quality medium to first passengers of the vehicle desiring high quality entertainment by outputting a high quality signal, and a low quality entertainment system for playing a low quality medium to second passengers of the vehicle by outputting a low quality signal, the second passengers having no preference between the high quality entertainment and low quality entertainment. In addition, the entertainment system includes a controller monitoring the high and low quality signals output from the high and low quality entertainment systems respectively, and outputting a control signal to control switching between the high and low quality entertainment systems and the front and rear speakers responsive to the high and low quality signals.

Abstract: Stereo audio signals of right and left channels are inputted to a stereo surround system. The stereo surround system is provided with: a right side speaker group including at least two speakers arranged vertically; and a left side speaker group arranged at a left side of the right side speaker group, and including at least two speakers arranged vertically. The stereo surround system is further provided with a process device, coupled to the right side speaker group and the left side speaker group, for processing the inputted stereo audio signal of the right channel to generate at least two kinds of the surround signals to the right side speaker group, and for processing the inputted stereo audio signal of the left channel to generate at least two kinds of the surround signals to the left side speaker group.

Abstract: A sound field controller for generating apparent sound sources by adjusting the amplitude and delay time of a sound signal so that the sound will be perceived by plural listeners as sound coming from a location separated from the specific location of the front speakers, and for additionally controlling the effect of the apparent sound sources by evaluating the attributes of the source sound signal.

Abstract: This invention relates to a audio system installed in a vehicle. An apparatus for reproducing a sound field according to the invention includes a fader controlling circuit for separating a sound signal into predetermined channels to adjust a level of each separated sound signal depending on an amount of manipulation of a fader manipulating part, a sound field controller for performing a computing process of each sound signal obtained by the fader controlling circuit to form a desired sound inside a vehicle, and a relieving part invalidating a separate adjustment for the sound signal caused by the manipulation of the fader manipulating part while the sound field controller is operated.

Abstract: A method and apparatus for generating control voltage signals in a surround sound processor is disclosed which utilizes a on-shot monostable multivibrator for minimizing intermodulation distortion while following rapid directional change yet minimizing intermodulation distortion. The apparatus includes means for smoothing the directional information signals derived from audio input signals each with a continuously variable time constant to generate a corresponding control voltage signal, such that each time constant depends inversely upon the magnitude of the difference between the directional information signal applied thereto and the corresponding control voltage signal generated thereby.

Abstract: Left right and surround components of a stereo signal are coded into a monaural and small co-channel providing volume steering for recreating a stereo effect with a substantially reduced bit rate. The signal is split into a sum and difference signal, the difference signal is randomized and the sum is added to the randomized difference to comprise the single audio channel. A functional relationship is solved for left and right volumes which is then transmitted for intervals on the co-channel. Decoding of the single transmission channel directs it to left, right, or surround channels based on decoding on the logic co-channel. The co-channel updates left and right volume levels which are interpolated through time to effect smooth volume change. Surround gain is determined from left and right channel gains to maintain unity total volume, with the sum of the squares of the three volume controls being unity.

Abstract: A multi-channel sound simulation system for processing a stereophonic signal having a high frequency component for use with at least a pair of primary loudspeakers and a pair of secondary loudspeakers includes a receiving member for receiving the stereophonic signal and for producing a first primary channel signal and a second primary channel signal. The first and second primary channel signals are adapted to be respectively applied to a first primary loudspeaker and a second primary loudspeaker. The receiving member is further adapted to divide the input signal into a first secondary channel signal and a second secondary channel signal. The first and second secondary channel signals are fed through a roll-off member which inhibits the high frequency component of the signal, thereby producing inhibited first and second secondary channel signals.

Abstract: In the sound field control device, main signals and a surround signal are generated on the basis of input left and right 2 channel signals, and 4 channel main sound field signals and 4 channel surround sound field signals which are respectively aggregations of reflected sound signals of various directions in the respective sound fields are generated on the basis of reflected sound parameters of sound fields established with respect to the main signals and the surround signal, and the 4 channel main sound field signals and the 4 channel surround sound field signals of each corresponding channel are combined together and provided as 4 channel sound field signals to be sounded. Reflected sounds are created on the basis of reflected sound parameters of a certain established sound field regardless of sound field components contained in a source signal and output as a sound field signal.

Abstract: A surround audio apparatus is comprised of an input terminal to which a stereo audio signal encoded for surround reproduction is supplied, an analog-to-digital converter for converting the stereo audio signal supplied to the input terminal into a digital audio signal, a digital signal processor for decoding the digital audio signal converted by the analog-to-digital converter in a surround stereo reproduction fashion to output a digital surround signal, a digital-to-analog converter for converting the digital surround signal from the digital signal processor into an analog surround signal, and an output terminal from which the analog surround signal from the digital-to-analog converter is delivered.

Abstract: A audio surround system particularly arranged for use in a theater provides the enhanced ambience and wide sound image advantages of a stereo enhancement system (SRS system) having directivity servos. A stereo enhancement system known as the "SRS" enhancement system enables a pair of relatively closely spaced speakers to provide a wide sound image lacking in any apparent point source and having enhanced directivity. A first SRS system (10) is modified for use with a set of front speakers (16,22,26) by increasing speed of its directivity servos (80), minimizing "pumping" caused by the increased directivity servo speed, increasing its threshold, and providing a bleed for minimizing reverberation effect. A similar SRS system (34) drives a set of rear speakers (40,46,50) and is differently modified to eliminate certain high pass filters (86,110), increase speed of its directivity servos (80), and to feed only ambience signals to left and right rear speakers (40,46).