Abstract: A method for processing an audio signal during the multi-channel audio coding is disclosed. The present invention provides the method for processing an audio signal comprising: generating a fixed output channel using a down-mix signal and a basic matrix; and generating an arbitrary output channel using the fixed output channel and a post matrix.

Abstract: The invention concerns the processing of audio data. The invention is characterized in that it consists in: (a) encoding signals representing a sound propagated in three-dimensional space and derived from a source located at a first distance (P) from a reference point, to obtain a representation of the sound through components expressed in a spherical harmonic base, of origin corresponding to said reference point, (b) and applying to said components compensation of a near-field effect through filtering based on a second distance (R) defining, for sound reproduction, a distance between a reproduction point (HPi), and a point (P) of auditory perception where a listener is usually located.

Abstract: To provide a surround sound reproducing system capable of obtaining high realistic sensation even in the case where an integral surround speaker cannot be installed rearward of a listening position. A surround system 100 is constructed by: a sound source output device 110 for outputting bit stream data of a predetermined format; a signal processor 120 for performing a signal process on every audio signal of each channel; and a speaker system 130 made of various speakers corresponding to various channels and including an integral surround speaker. The signal processor 120 has a signal processing unit 200 including: a switch control unit 203 for selecting one of right and left surround signals amplified from a surround speaker; a frequency correcting circuit 204 for correcting the frequency characteristic of the surround signal selected by the switch control unit 203; and an adder 205 for adding the surround signal whose frequency characteristic was corrected to a main signal.

Abstract: A sound reproducing apparatus for providing an optimal virtual sound source and a sound reproducing method therefor are provided. The sound reproducing apparatus includes a virtual sound signal generation unit for generating more than one virtual sound signal corresponding to locations and the number of target virtual sound sources on the basis of more than one inputted sound signal, and a virtual sound signal downmix unit for downmixing said more than one virtual sound signal to virtual sound signal outputs corresponding to a predetermined number of output channels. The number and locations of diversely variable virtual sound sources are provided, thereby obtaining an effect of providing an optimal virtual sound source adaptively depending on each different environment.

Abstract: A method for processing sound signal including an L side enhanced difference signal comprising a sum of a signal being removed low frequency component from L?R signal and an L+R signal, an R side enhanced difference signal comprising a sum of a signal being removed low frequency component from R?L signal and an R+L signal, an L side output signal comprising a subtraction of signals, in which said R side enhanced difference signal being delayed to remove low and high ranges and amplified by a predetermined amplifying rate for a purpose of cross cancellation talk is subtracted from said L side enhanced difference signal and an R side output signal comprising a subtraction of signals, in which said L side enhanced difference signal being delayed to remove low and high ranges and amplified by a predetermined amplifying rate for a purpose of cross cancellation talk is subtracted from said R side enhanced difference signal.

Abstract: A method to process audio signals, an apparatus accepting audio signals, a carrier medium that carried instructions for a processor to implement the method to process audio signals, and a carrier medium carrying filter data to implement a filter of audio signals. The method includes filtering a pair of audio input signals by a process that produces a pair of output signals corresponding to the results of: filtering each of the input signals with a HRTF filter pair, and adding the HRTF filtered signals. The HRTF filter pair is such that a listener listening to the pair of output signals through headphones experiences sounds from a pair of desired virtual speaker locations.

Abstract: A method to process audio signals, an apparatus accepting audio signals, a carrier medium that carried instructions for a processor to implement the method to process audio signals, and a carrier medium carrying filter data to implement a filter of audio signals. The method includes filtering a pair of audio input signals by a process that produces a pair of output signals corresponding to the results of: filtering each of the input signals with a HRTF filter pair, and adding the HRTF filtered signals. The HRTF filter pair is such that a listener listening to the pair of output signals through headphones experiences sounds from a pair of desired virtual speaker locations.

Abstract: The method comprises generating an acoustical volume velocity Q in the listening position, measuring a response quantity p, such as sound or vibration, at a suspected source position resulting from the volume velocity Q, and determining the acoustical transfer impedance Zt as the response quantity p divided by the acoustical volume velocity Q, Zt=p/Q. According to the invention the acoustical volume velocity Q is generated using a simulator (10) simulating acoustic properties of at least a head of a human being, the simulator comprising a simulated human ear (14, 15) with an orifice in the simulated head and a sound source (30) for outputting the acoustical volume velocity Q through the orifice. The output volume velocity Q from the orifice of an ear is estimated from measurements with two microphones inside the corresponding ear canal.

Abstract: A method for generating a sound giving a sensation of depth by applying, after extraction, a transfer function quadrille onto electric sound signals on the left and right thereof. The transfer functions simulate the trajectories taken by the sound associated with the electric signal to be processed in order to reach two receivers, if this sound was emitted in air. The signals that have been processed, one by one, by one of the four transfer functions of the quadrille, are combined with each other, then the sound signal thus obtained is mixed with the original electric sound signal to be processed after a temporal reset.

Abstract: Systems and processes for transmission of multi-channel audio from a sender to one or more recipients. Multi-channel audio is encoded with a plurality of different dialog channels. The encoded multi-channel audio and dialog channels can be compressed to facilitate transmission with limited bandwidth. A recipient can select a desired dialog channel from the plurality of dialog channels transmitted. A receiver side decoder can reconstruct a multi-channel audio with the selected dialog for playback. The plurality of dialog options can include different languages, different dialects, different accents, and/or different viewpoints/biases.

Abstract: There is described a multi-channel encoder (10; 600) for processing input signals conveyed in N input channels to generate corresponding output signals conveyed in M output channels together with complementary parametric data; M and N are integers wherein N>M. The encoder (10; 600) includes a down-mixer for down-mixing the input signals to generate the corresponding output signals, the encoder also comprising an analyser for processing the input signals to generate the parameter data, said parametric data describing mutual differences between the N channels of input signal to allow for regenerating during decoding one or more of the N channels of input signals from the M channels of output signal. Such an encoder (10; 600) is capable of providing highly efficient data encoding and also of being backwards compatibility with relatively simpler decoders having fewer than N decoding output channels. The invention also concerns decoders (800) compatible with such a multi-channel encoder (10; 600).

Abstract: A scheme for stereo and multi-channel synthesis of inter-channel correlation (ICC) (normalized cross-correlation) cues for parametric stereo and multi-channel coding. The scheme synthesizes ICC cues such that they approximate those of the original. For that purpose, diffuse audio channels are generated and mixed with the transmitted combined (e.g., sum) signal(s). The diffuse audio channels are preferably generated using relatively long filters with exponentially decaying Gaussian impulse responses. Such impulse responses generate diffuse sound similar to late reverberation. An alternative implementation for reduced computational complexity is proposed, where inter-channel level difference (ICLD), inter-channel time difference (ICTD), and ICC synthesis are all carried out in the domain of a single short-time Fourier transform (STFT), including the filtering for diffuse sound generation.

Abstract: The beginning detection, accommodation and frequency bias properties of the human hearing mechanism have been modeled to create systems that can detect directional transients (“sound events”) in a sound field and localize them. These systems break down a sound field into sound events and non-sound events and separately localize the sound events and non-sound events. Sound events are generally identified according to the frequency bias and beginning detection properties. Once detected, the sound events are generally localized according to differential steering angles (steering angles to which the steady-state signals have been accommodated) or ordinary steering angles, both of which reflect the direction of a sound event indicated during the rise-time of the sound event. When no sound events are detected, non-sound events are localized according to a steering angle that does not reflect rapid motion.

Abstract: A system and a method for correcting, simultaneously at multiple-listener positions, distortions introduced by the acoustical characteristics includes warping room responses, intelligently weighing the warped room acoustical responses to form a weighted response, a low order spectral fitting to the weighted response, forming a warped filter from the low order spectral fit, and unwarping the warped filter to form the room acoustical correction filter.

Abstract: A system for 3D sound processing. The system includes a first processing section including a first left lattice filter and a first right lattice filter, respectively electrically connected to a second left lattice filter and a second right lattice filter, and including two negative couplers, each electrically connected to the first left and right lattice filters and also electrically connected to the second left and right lattice filters, and a second processing section including a left filter and a right filter, respectively electrically connected to the second left lattice filter and the second right lattice filter.

Abstract: A process for combining audio channels combines the audio channels to produce a combined audio channel and dynamically applies one or more of time, phase, and amplitude or power adjustments to the channels, to the combined channel, or to both the channels and the combined channel. One or more of the adjustments are controlled at least in part by a measure of auditory events in one or more of the channels and/or the combined channel. Applications include the presentation of multichannel audio in cinemas and vehicles. Not only methods, but also corresponding computer program implementations and apparatus implementations are included.

Abstract: A distributing circuit distributes audio signals of a predetermined number of channels to audio signals of a predetermined number of channels. A first signal processing circuit processes audio signals that are output from the distributing circuit in parallel, reproduces the resultant signals with a plurality of speakers, and localizes sound images of the individual audio signals at predetermined positions. A second signal processing circuit inputs audio signals that are output to the plurality of speakers and performs signal processes equivalent to the transfer functions from the individual speakers to both the ears of the listener. The output signals of the second signal processing circuit are reproduced with the headsets.

Abstract: The beginning detection, accommodation and frequency bias properties of the human hearing mechanism have been modeled to create systems that can detect directional transients (“sound events”) in a sound field and localize them. These systems break down a sound field into sound events and non-sound events and separately localize the sound events and non-sound events. Sound events are generally identified according to the frequency bias and beginning detection properties. Once detected, the sound events are generally localized according to differential steering angles (steering angles to which the steady-state signals have been accommodated) or ordinary steering angles, both of which reflect the direction of a sound event indicated during the rise-time of the sound event. When no sound events are detected, non-sound events are localized according to a steering angle that does not reflect rapid motion.

Abstract: An audio enhancement system and method for use receives a group of multi-channel audio signals and provides a simulated surround sound environment through playback of only two output signals. The multi-channel audio signals comprise a pair of front signals intended for playback from a forward sound stage and a pair of rear signals intended for playback from a rear sound stage. The front and rear signals are modified in pairs by separating an ambient component of each pair of signals from a direct component and processing at least some of the components with a head-related transfer function. Processing of the individual audio signal components is determined by an intended playback position of the corresponding original audio signals. The individual audio signal components are then selectively combined with the original audio signals to form two enhanced output signals for generating a surround sound experience upon playback.

Abstract: To date, there has been no speaker-characteristic compensation method including a processing step of reducing crosstalk between speakers incorporated in a mobile terminal. Accordingly, it has been impossible to reduce crosstalk that, in a mobile terminal, occurs between speakers. A speaker-characteristic compensation method, for a mobile terminal device having at least two speakers in a case, according to the present invention includes steps of reducing mutual crosstalk between the speakers, thereby reducing crosstalk between the speakers.

Abstract: A data processing apparatus is designed for simulating an acoustic characteristic of an acoustic space which contains a sound source for generating a sound and a sound receiving point for receiving the sound. In the apparatus, each of a plurality of characteristic control sections processes sound data and outputs the processed sound data. The characteristic control sections correspond to transmission paths which must exist in the acoustic space such that the sound generated from the sound source travels to the sound receiving point through the respective transmission paths. An instruction section provides a processing instruction of the sound data to each characteristic control section such that each characteristic control section processes the sound data according to the provided processing instruction to thereby execute the simulation of the sound traveling through the corresponding transmission path.

Abstract: To increase the stereophonic potential of an ordinary stereo source, a device (20) eliminates the common signals from a stereo source. The device is installed in relation to four loudspeakers, two primary (38, 40) and two secondary (42, 44), and it includes a stereo input (34, 36) and an electric circuit that links the two secondary loudspeakers. The primary loudspeakers reproduce unaltered stereo signals and the secondary loudspeakers reproduce altered signals where (by hand: when) the circuit has eliminated the common signals from the two channels of the primary stereo source. Since all “mono” components of the sound [by hand: same amplitude, same frequency] have been eliminated from the secondary outputs, we obtain a “purely stereo” source. An additional channel (45) can be added in order to reproduce the common components of the stereo source.

Abstract: In processing a multi-channel audio signal having at least three original channels, a first downmix channel and a second downmix channel are provided, which are derived from the original channels. For a selected original channel of the original channels, channel side information are calculated such that a downmix channel or a combined downmix channel including the first and the second downmix channels, when weighted using the channel side information, results in an approximation of the selected original channel. The channel side information and the first and second downmix channels form output data to be transmitted to a decoder, which, in case of a low level decoder only decodes the first and second downmix channels or, in case of a high level decoder provides a full multi-channel audio signal based on the downmix channels and the channel side information.

Abstract: A method of encoding a multichannel signal, such as a stereophonic audio signal, including at least first and second signal components includes transforming at least the first and second signal components by a predetermined transformation into a principal signal including most of the signal energy and at least one residual signal including less energy than the principal signal. The predetermined transformation is parameterized by at least one transformation parameter. The method further includes representing the multichannel signal at least by the principal signal and the transformation parameter.

Abstract: The apparatus for constructing a multi-channel output signal using an input signal and parametric side information, the input signal including the first input channel and the second input channel derived from an original multi-channel signal, and the parametric side information describing interrelations between channels of the multi-channel original signal uses base channels for synthesizing first and second output channels on one side of an assumed listener position, which are different from each other. The base channels are different from each other because of a coherence measure. Coherence between the base channels (for example the left and the left surround reconstructed channel) is reduced by calculating a base channel for one of those channels by a combination of the input channels, the combination being determined by the coherence measure. Thus, a high subjective quality of the reconstruction can be obtained because of an approximated original front/back coherence.

Abstract: Sound processing systems have been developed that create a surround effect without quality degradation experienced by known sound processing systems in non-optimum listening environments. The sound processing systems may include matrix decoding systems that manipulate input signals prior to converting them into a number of output signals so that the output signals are a function of a greater number of input signals. These sound processing systems may also or alternately include a bass management system that from the input signals preserves the low frequency components of the input signals in separate channels. Both the matrix decoding systems and bass management systems may also produce additional signals. Further, the matrix decoding and bass management systems may be implemented separately or jointly in vehicular sound systems.

Abstract: A multi-channel audio reproduction apparatus and method for loudspeaker reproduction using virtual sound images whose positions can be adjusted is provided. The multi-channel audio reproduction apparatus includes a virtual sound image forming unit for compensating for the occurrence of cross-talk in at least one input audio signal according to the arrangement of loudspeakers, obtaining transfer functions occurring when sound from a position in a three dimensional space is transmitted to both ears of a listener, and forming a plurality of first virtual sound images in a three dimensional space using the transfer functions. A controller generates adjusting factors for adjusting the position of at least one second virtual sound image.

Abstract: The present invention relates to audio visual devices, and is aimed to provide an audio box with stereo surround effect; an integrated multi-channel audio box having simple structure and neat appearances, no complex wiring necessary to connect to the source. The structure of the audio box is in rectangular shape. There are three or more than three independent audio channels, including at least one base channel. The present invention adopts one audio box instead of the current stereo system structure with many audio boxes; three or more than three independent channels are integrated into one rectangular audio box, the wiring connection between the audio boxes and source is greatly simplified. Only one cable is necessary to carry out the communication among all channels, or wireless connection can be adopted.

Abstract: Audio sources in typical computer systems provide different numbers of channels of audio signals to a mixing component of the operating system. This conventional arrangement usually prevents the audio signals from all sources from being played back through all output channels. Novel arrangements of upmixing and mixing components are disclosed that allow audio signals to be delivered to all output channels regardless of the configuration of the audio sources and the number of channels that are provided by those audio sources.

Abstract: A method and system accept left and right channel inputs of audio data and provide output audio data for at least three channels in a fashion that may effect a facsimile of the original soundstage on which the left and right inputs were recorded.

Abstract: A method derives at least three audio signals, each associated with a direction, from two input audio signals. In response to the two input signals, a passive matrix generates a plurality of passive matrix audio signals, including two pairs of passive matrix audio signals, a first pair of passive amtrix audio signals represent directions lying on a first axis and a second pair of passive matrix audio signals represent direction lying on a second axis, the first and second aces being substantially at ninety degrees to ach other. The pairs of passive matrix audio signals are processed to derive a plurality of matrix coefficients therefrom, The processing includes deriving a pair of intermediate signals and urging each pair of intermediate signals toward equality in response to a respective error signal. At least three output signals are produced by matrix multiplying the two input signals by the matrix coefficients.

Abstract: A motion picture soundtrack reproduction system has a center front soundtrack channel and a plurality of other soundtrack channels. A volume control adjusts the gain of all the channels. The volume control has a range of settings from a minimum to a maximum, the gain of the center front channel having substantially a first relationship to the volume control settings and the gain of the other channels having substantially a second relationship to the volume control settings, the relationships being such that for a range of volume control settings less than a first setting the gain of the center front channel remains substantially constant while the gain of the other channels decreases as the setting decreases or decreases more gradually than the gain of the other channels as the setting decreases.

Abstract: An apparatus and method of generating multi-channel audio signals includes a voice signal removal unit to generate a first signal by removing one or more components of a plurality of frequency bands corresponding to a voice frequency range from an input signal, a voice signal amplification unit to generate a second signal by calculating a sum of channel signals of the input signal and amplifying one or more components of the plurality of the frequency bands corresponding to the voice frequency range of the sum signal, a control filter to generate a third signal by compensating for a level of the first signal, and a multi-channel audio generation unit to generate a center-channel audio signal and a front-channel audio signal using the second, third, and fourth signals.

Abstract: An audio enhancement system and method for use receives a group of multi-channel audio signals and provides a simulated surround sound environment through playback of only two output signals. The multi-channel audio signals comprise a pair of front signals intended for playback from a forward sound stage and a pair of rear signals intended for playback from a rear sound stage. The front and rear signals are modified in pairs by separating an ambient component of each pair of signals from a direct component and processing at least some of the components with a head-related transfer function. Processing of the individual audio signal components is determined by an intended playback position of the corresponding original audio signals. The individual audio signal components are then selectively combined with the original audio signals to form two enhanced output signals for generating a surround sound experience upon playback.

Abstract: A sound processing system adaptively mixes active matrix decoding and passive matrix processing of incoming audio signals. Mixed output signals are generated with active matrix decoding where the audio signals are stereo. Mixed output signals are generated with passive matrix processing where the audio signals are monaural. The sound processing system reduces the degree of active matrix decoding in the mixed output signals where the incoming audio signals are stereo and monaural. The sound processing system also generates virtual stereo signals from incoming audio signals having monaural signals. Mixed output signals are generated of the virtual stereo signals using active matrix decoding.

Abstract: A method and circuit for deriving a set of multichannel audio signals from a conventional monaural or stereo audio signal uses an auxiliary multichannel spectral mapping data stream. Audio can be played back in stereo and multichannel formats from a conventional stereo signal on compact discs, FM radio, or other stereo or monaural delivery systems. The invention reduces the data rate needed for the transmission of multichannel digital audio.

Abstract: A central speaker and personal headset speakers are used to create a three-dimensional phantom sound space for each listener. The speakers of the headset are located in close proximity to, but do not isolate, the ears of the listener such that external sounds are allowed to impinge upon the pinna of the ears. The headset speakers form an isosceles triangle with the distant central speaker as the apex. This speaker configuration with personal controls can achieve a state of sound equilibrium for a phantom three-dimensional sound space. The sound signal may be synchronized with a video signal, and the sound pressure level of the left and right speakers can be adjusted to control the listener's perception of the virtual movement of phantom sound source image within the sound space according to changes in the point of view represented in a displayed video image.

Abstract: A method and apparatus for processing multi-channel audio signals in which the channels are processed by one of alternatively selectable processes to produce an alternatively selectable number of output channels, the process being responsive to information contained in the input signal.

Abstract: The present invention relates to methods and devices for processing one or the other of two types of common input audio stereo signals so that the output signals will reproduce normally wide stereo sound from an audio stereo reproduction system comprising a pair of identical loudspeakers positioned adjacent or close to each other. Thus, the invention relates partly to a method and a device for producing that specific pair of left and right output signals from one kind (M+S) of input signals, and partly to a method and a device for producing a similar type of left and right output signals from another kind (L+R) of input signals. Finally, the invention relates to an audio stereo signal reproduction system comprising a pair of identical louspeakers positioned adjacent or close to each other and intended for reproduction of normally wide stereo sound from one (M+S) of said kinds of input signals.

Abstract: In a multi viewer environment where multiple viewers simultaneously experience an audio-visual production, with the visual production occurring on a display surface, a method of increasing the perceived reality of the audio stream of the production, the method comprising the steps of: (a) locating a series of speakers along a periphery of the viewing audience; (b) panning an audio stream between the series of speakers so as to provide for the sense of an audio sound moving along the side of the viewing audience. In preferred embodiments, the output of one of the speakers is delayed relative to another speaker.

Abstract: An audio user interface is provided in which items are represented in an audio field by corresponding synthesized sound sources from where sounds related to the items appear to emanate. At least some of the sound sources are associated in a collection as members of the collection; the collection itself has an associated collection-representing sound source. The collection can be changed in either direction between an un-collapsed state in which the member sound sources are present un-muted in the audio field, and a collapsed state in which the member sound sources are muted with the collection-representing sound source providing an audible presence for the collection in the audio field.

Abstract: A method of processing and reproducing an input audio stereo signal in an audio signal processing system comprises the steps of (1) splitting a side signal into a first and a second intermediate signal, where the first intermediate signal is equal to the side signal and the second intermediate signal is equal to the first intermediate signal phase shifted 180°, (2) attenuating the mid signal by a factor a which compensates for imperfections in the balance between the mid and side signals appearing in the audio reproduction stage, (3) adding the attenuated mid signal to both of the first and second intermediate signals, so as to form the output audio stereo signal, and (4) directing the output stereo signal to an audio stereo signal reproduction system, comprising a pair of loudspeaker units located in close proximity to each other.

Abstract: The present invention provides a method of decoding two-channel matrix encoded audio to reconstruct multichannel audio that more closely approximates a discrete surround-sound presentation. This is accomplished by subband filtering the two-channel matrix encoded audio, mapping each of the subband signals into an expanded sound field to produce multichannel subband signals, and synthesizing those subband signals to reconstruct multichannel audio. By steering the subbands separately about an expanded sound field, various sounds can be simultaneously positioned about the sound field at different points allowing for more accurate placement and more distinct definition of each sound element.

Abstract: A universal four-channel multimedia computer speaker system is connectable to audio sub-system control circuits (e.g., “sound cards”) of both the four-channel type and the conventional two-channel (stereo) type. With the audio sub-system control circuit being of a four-channel type, the universal four-channel audio system functions as a conventional multimedia computer four-channel surround sound audio system. With a four audio channel multimedia computer work and the audio sub-system control circuit being of a conventional two-channel (stereo) type, the universal four-channel audio system is configured to provide one pair of wide-band speakers (e.g., the front) with distinct audio playback according to respective right-front and left-front audio channels in a four or two audio channel multimedia computer work such as a game, music, etc.

Abstract: Various equivalent adaptive audio matrix arrangements are disclosed, each of which includes a feedback-derived control system that automatically causes the cancellation of undesired matrix crosstalk components in the matrix output. Each adaptive audio matrix arrangement includes a passive matrix that produces a pair of passive matrix signals in response to two input signals. A feedback-derived control system operates on each pair of passive matrix signals, urging the magnitudes of pairs of intermediate signals toward equality. Each control system includes variable gain elements and a feedback and comparison arrangement generating a pair of control signals for controlling the variable gain elements. Additional control signals may be derived from the two pairs of control signals for use in obtaining more than four output signals from the adaptive matrix.

Abstract: A setting up operation for connecting a number of speakers can be easily executed by a system in which setups and pattern numbers are stored in a memory. When the user operates an operation input unit and selects an easy setup, a default setting pattern number is read out from the memory and displayed on the display. The user operates encoders by watching display contents on a display. When the pattern number corresponding to his own speaker construction obtained by a chart or the like is displayed, he determines it by a key operation. A microcomputer stores the determined pattern number in a memory and the speaker setup corresponding to the pattern number is read out from a ROM in the microcomputer. Each unit of an acoustic apparatus is controlled on the basis of the read-out speaker setup, thereby performing the speaker setup. The user can perform the speaker setup merely by inputting the pattern number using the encoders.

Abstract: A system and method of producing an output sound field that is representative of an input sound field compatible with both existing prior art sound reproduction systems, for example ITU 5.1/6.1, and with a three-dimensional reproduction system unique to this disclosure. One embodiment of the disclosed system is comprised of a microphone array, an encoder, a decoder, and a plurality of speakers, some of which may not be located in the plane of the listener. A further embodiment discloses matrices to encode and decode the signals representative of the input and output sound fields respectively.

Abstract: The disclosed embodiments relates to orienting a sound field in relation to a user and a generated set of images. For instance, a system may include a sound subsystem, a location subsystem, and a speaker subsystem. The speaker subsystem may include a plurality of sensors and a plurality of speakers. The sound subsystem may include a surround sound circuit that may be connected to a signal source and the speaker subsystem. The location subsystem may receive position information reflective of the orientation of a user and provide a signal that may be used by the sound circuit to adjust the audio signal based on the orientation of the user.

Abstract: The invention generally relates to a method and apparatus for taking an input signal, replicating it a number of times and modifying each of the replicas before routing them to respective output transducers such that a desired sound field is created. This sound field may comprise a directed beam, focussed beam or a simulated origin. In a first aspect, delays are added to sound channels to remove the effects of different travelling distances. In a second aspect, a delay is added to a video signal to account for the delays added to the sound channels. In a third aspect, different window functions are applied to each channel to give improved flexibility of use. In a fourth aspect, a smaller extent of transducers is used top output high frequencies than are used to output low frequencies. An array having a larger density of transducers near the centre is also provided. In a fifth aspect, a line of elongate transducers is provided to give good directivity in a plane.

Abstract: The invention relates to a method of reproducing multichannel audio sound via several real and at least one virtual speaker (2, 3, 4, 5, 6, 9, and 10). According to the invention, the audio sound envisaged for a real speaker (2, 3, 4, 5, and 6) is reproduced partly via the real speaker (2, 3, 4, 5, and 6) and partly via a virtual speaker (9 and 10) positioned in the same location.