Abstract: A sound imaging system, which by processing left and right stereo channel audio signals of a conventional two channel stereo system, distributes signals to a speaker array of a number of speakers determined by a listening area. Listeners located in different places within the listening area, can have an audible perception of an equivalent distribution to that of the conventional two channel stereo system. Additionally they will have an audible central perception of the centered program material equivalent to that obtained from the conventional two channel stereo system when the listeners are located in a median plane of the conventional two channel stereo system speakers.

Abstract: In a first mode where no audio reproduction is to be executed in a second zone, each selector switch shifts to a Z1 contact. In a second mode where audio reproduction is to be executed in the second zone, each selector switch shifts to a Z2 contact. In the second mode, a DSP executes sound field correction on main and rear signals such that sound fields in the first zone have desired characteristics. Setting section can select either a first speaker mode where speakers connected to first output terminals and speakers connected to second output terminals are both positioned in the first zone, or a second speaker mode where the speakers connected to the first output terminals are positioned in the first zone and the speakers connected to the second output terminals are positioned in the second zone. When the output to the first output terminals is off while the output to the second output terminals is on in the second speaker mode, the DSP stops outputting the surround signals.

Abstract: A method for realizing virtual multi-channel by spectrum analysis is disclosed. The low-frequency-effect sound data is obtained by averaging sound data of left and right channels in the two-channel sound source and filtering the average by a first low pass filter. The central channel sound data is obtained by averaging sound data of the left and the right channels in the two-channel sound source and filtering the average by a second low pass filter. The surround right and left sound data is obtained by copying sound data of the left and the right channels in the two-channel sound source, respectively.

Abstract: A method and an apparatus for producing multi-channel stereophonic sound by which output 5.1-channel sound is converted into 7.1-channel sound are provided. An encoded audio stream is received and decoded. The decoded audio stream is reproduced as sound through 5.1 channels. Outputs of left and right speakers of a TV set are also produced using signals of a left stereo channel, a right stereo channel, and a center channel of the 5.1 channels.

Abstract: There provided a sound data delay unit for delaying sound data of a plurality of channels in a single memory area, the sound data delay unit wherein, when delay amount assigned to each channel is input into an address information generator, the address information generator generates address information for assigning storage area of the sound data for each channel in a memory, and a selector inputs the address information into the memory with respect to each channel and assigns the storage area for each channel.

Abstract: A technique for panning over four speakers utilizes an internal three-channel representation (Left, Right, W) where all channel weights are positive. The three channels are combined by a decoder to drive pairs of front and back speakers.

Abstract: A sound field effect control apparatus and and a sound field effect control method are provided, which are capable of enabling a listener to listen to reflected sounds close to initial reflected sounds generated in an actual acoustic space, by utilizing information reflecting the position of a sound source possessed by multichannel audio source signals. Sound field effects are applied to multichannel audio source signals that are input to a sound field effect control apparatus. The multichannel audio source signals cause sound generated from an imaginary sound source at a predetermined position to be heard by the listener when converted into sound and generated by a plurality of loudspeakers. Multichannel initial reflected sound signals corresponding to initial reflected sounds that will be heard by the listener when the sound is generated from said imaginary sound source at said predetermined position in a predetermined acoustic space, are generated from the multichannel audio source signals.

Abstract: A matrix surround decoding system comprises a DIR 10 detecting a sampling frequency FS included in a stereophonic source, and a microcomputer 12 determining the type of stereo source on the basis of the sampling frequency detected by the DIR 10, and outputting to a matrix surround decoder 11 a mode switching signal CL for switching the output mode of the matrix surround decoder 11 to a mode corresponding to the determined type of stereophonic source.

Abstract: A space surrounding a sound source (S) which is set in a sound field (10) to be reproduced is divided into sound source element regions (S1 to Sn), and a space surrounding a sound receiving point (R) is divided into sound receiving element regions (R1 to Rm). An impulse response when a sound radiated from the sound source (S) is emitted from one of the sound source element regions (S1 to Sn), passes through the sound field (10), enters one of the sound receiving element regions (R1 to Rm), and then reaches the sound receiving point (R) is obtained for each of combinations of the sound source element regions (S1 to Sn) and the sound receiving element regions (R1 to Rm). A sound emitted from a real sound source (Sr) in an arbitrary real space (26) is picked up by microphones (MC1 to MCn) placed correspondingly with the sound source element regions (S1 to Sn).

Abstract: The production of multidirectional or instantaneous live virtual surround sound broadcasting is obtained by positioning a plurality of microphones on an oval frame in a predetermined pattern and with a predetermined orientation, connecting the microphones to a virtual surround semiconductor chip and connecting outputs from the semiconductor chip to a pair of speakers.

Abstract: A video game apparatus in which a specified event is executed in a game space displayed on a monitor, and a plurality of background sounds having different attributes are outputted at a specified output ratio from a plurality of sound output units spaced apart from each other, comprising: a recording unit for storing the plurality of background sounds as background sound data, and a background sound control unit for setting the output ratio of the background sounds having different attributes to be output from the sound output units according to a viewing point and a viewing direction in the game space while reading the background sound data from the recording unit and outputting them from the plurality of sound output units.

Abstract: This invention provides a system capable of transitioning from surround sound effect to stereo sound effect, and then to a monophonic sound effect using front speakers. A user may control the amount of surround sound effect that is combined with stereo sound effect, and the amount of stereo sound effect that is combined with monophonic sound effect. The user may also control the system to hear pure surround sound effect, stereo sound effect, or monophonic sound effect. The system may allow a user to control the contribution of a particular sound effect by controlling the relative proportions of the filtered dipole signals and the attenuated unfiltered dipole signals. The signal processing may be also done through an analog device. The system may also process some audio channels in an inverted form and compensate for these inversions by reversing the polarity of that output to the speaker, as well as accept two-channel and four-channel audio inputs.

Abstract: A surround sound field reproduction system and method is disclosed by which, in such a case that a listener changes its posture so that a portion of a video image to which attention should be paid may be observed in front of the listener, a sound image can be localized accordingly in a direction in which the video image is observed in front of the listener. Specifically, the surround sound field reproduction apparatus includes a plurality of horizontal panners for receiving a plurality of sound signals from microphones disposed horizontally and cooperating with each other to control the horizontal localization, and a vertical panner for receiving sound signals from microphones disposed vertically to control the vertical localization. The horizontal panners level-distribute the received sound signals to a plurality of output channels provided corresponding to surround reproduction output channels.

Abstract: A two-channel sound recording and play-back system for providing a holophonic reproduction or play-back of sounds is herein disclosed. The two-channel recording system comprises cables and electronic apparatus for providing a stereophonic type of recording, where a plurality of microphones are arranged in an adjoining mutually angled relationship so as to provide, during the recording operation, a stereophonic effect due to phase differences at each frequency and an intensity difference at least for middle-high acoustic frequencies.

Abstract: A method of generating surround sound with channels processing separately includes steps of transmitting left and right channel signals separately to a first multiple frequency phase shift processor, a pre-set equalizer and a second multiple frequency phase shift processor without addition and subtraction thereby providing a stereo sound position enhancement processing, transmitting left and right space signals separately to two multiple frequency phase shift processors, two stereo signal difference processors and a pre-set equalizer to provide a surround sound enhancement processing, and transmitting left channel signals, left space signals, right channel signals and right space signals separately to respective variable amplifiers to adjust output amplitude after the sound position enhancement processing and the surround sound enhancement processing and then summing up output signals to obtain three dimensional effect enhancement.

Abstract: A sound signal encoding apparatus for encoding two different sound signals, comprising: compression level calculating means for calculating a compression level for each of the sound signal sections; compression level judging means for judging whether or not the calculated compression level for each of the sound signal sections exceeds a predetermined threshold compression value; frequency components encoding means for encoding the quantized frequency components for each of the sound signal sections to a multiplexed bit stream with a predetermined bit rate under two different states consisting of the first state in which the frequency components for each of the sound signal sections are compressed by the first frequency components compressing means when the compression level judging means is operative to judge that the compression level for each of the sound signal sections exceeds the predetermined threshold compression value and the second state in which the frequency components for each of the sound signal

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 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: Input sound signals are accepted for presentation to a plurality of speakers where the number of physically present speakers is less than the number of input sound signals. The accepted signals are expanded and summed in a manner such that a listener perceives sounds as coming from the same number of speakers as there are input signals while having less speakers actually operational. In one embodiment there is shown a five input system having only two speakers. The system is functional when the inputs are stereo or monaural and when there are all five speakers available.

Abstract: The inventive mechanism produces multiple output signals from a two-channel stereo input signal. The mechanism produces a first pair of output signals which retain the monaural information in the stereo input signal. The first pair of signals each comprise a combination of one of the input channels and filtered signal produced from a difference of both input channels. The mechanism produces a second pair of output signals which lacks the monaural information. The second pair of output signals each comprise a combination of one of the input channels and an inverse filtered signal produced from a difference of both input channels. Q-filters are used to provide the various filtered signals.

Abstract: A system and method for providing channel balancing and room tuning for a multi-channel audio surround sound speaker system passes source audio to automatically configured multi-channel compensation filters to provide equalization on a per channel basis for speakers having differing response characteristics. The speakers correspond to each of the surround sound channels. To automatically configure the multi-channel compensation filters, a controller generates common room tuning deviation data based on the frequency response characteristic data of each of the speakers. In addition, the system and method also generates room corrected channel deviation data for each channel by correcting a selected speaker response based on room tuning compensation requirement data derived from the common room tuning deviation data. Automatic channel balancing is provided by determining channel balancing compensation requirement data based on the corrected channel deviation data for each channel.

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 stereophonic image may be enhanced by splitting the left and right input audio signals into a plurality of left and right output signals in a plurality of audio frequency bands and then generating left and right output audio signals from the left and right output signals based on the magnitude of the differences between corresponding left and right output signals and also based upon the absolute magnitude of the left and right input audio signals themselves. In particular, a stereophonic image enhancement device according to the invention processes a left input signal and a right input signal using a first spectrum analyzer and a second spectrum analyzer which output a plurality of left output signals and right output signals corresponding to a plurality of frequency bands in response to the corresponding left input signal and right input signal.

Abstract: A digital surround sound decoder. The decoder uses an architecture including two signal processing chips to achieve a program that can decode audio data at sufficiently high resolution. The decoder performs in real time and is compatible with standard surround sound formats. The decoder includes software that utilizes table lookups for critical functions in the decoding process. The processing flow of the decoder's program takes advantage of the multi-function capability within the specific processors used in the design while using a minimum number of program instructions. The program implements band pass filtering, sum-difference calculations, fast-attack slow-decay integration, summation and reciprocal processing, determination of fast and slow modes, look-up table indexing, adaptive matrix processing and various other functions to generate decoded surround sound signals from encoded left and right signal inputs.

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 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: 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: 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 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 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: A digital surround sound decoder. The decoder uses an architecture including two signal processing chips to achieve a program that can decode audio data at sufficiently high resolution. The decoder performs in real time and is compatible with standard surround sound formats. The decoder includes software that utilizes table lookups for critical functions in the decoding process. The processing flow of the decoder's program takes advantage of the multi-function capability within the specific processors used in the design while using a minimum number of program instructions. The program implements band pass filtering, sum-difference calculations, fast-attack slow-decay integration, summation and reciprocal processing, determination of fast and slow modes, look-up table indexing, adaptive matrix processing and various other functions to generate decoded surround sound signals from encoded left and right signal inputs.

Abstract: Method and apparatus for implementing surround sound in an audio system having a number of audio output devices, and audio output buffers associated with the audio output devices adapted to output audio data in order of receipt. A block of delay data is loaded into a buffer associated with a rear audio output device. Audio data is directed to the audio output devices, by way of the buffers. In the operation of the system, data stored in the buffers is transferred from the buffers to the associated audio output devices. The audio data will be delayed reaching the rear audio output device until the delay data has been output from the buffer resulting in a surround sound effect.

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: 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 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: A method and an apparatus for processing audio signals with a directional emphasis by providing other channels besides the left and the right channels. An audio signal processing apparatus is divided into two blocks: a first block for processing digital signals of the left channel and the right channel supplied at each predetermined sampling period and outputting the signals of the left channel, right channel, and other channels which are amplified or decreased to a certain level; and a second block for detecting the level difference between the left channel signal and the right channel signal, and the level difference between the sum and the difference between the channel signals, and generating coefficients for adjusting the amplifying rate of the channels. The result is that the number of bits required for the signal processing can be reduced.

Abstract: In order to permit three-component (left, right and back) audio signals (LS, RS, BS) to be conveyed by a three-channel (left, right and mono) transmission system and still permit stereo and mono compatibility, the signals are encoded so that the three channels carry LS-1/2BS, RS-1/2BS and LS+RS+BS, respectively. Upon receipt, the signals can be decoded back to LS, RS and BS respectively. In a mono receiver without such a decoder, the signal LS+RS+BS on the mono channel is employed, and in a stereo receiver the signals LS-1/2BS and RS-1/2BS on the stereo channels are employed.

Abstract: In a sound reproduction system having two loudspeakers located in front of a listener, an input audio signal is divided into a plurality of channel signals which are respectively applied through voltage adjusting devices to the front loudspeakers and also to additional speakers or localization networks to generate additional real or phantom sound sources at .+-.90 degrees to the normal to the listener. The additional sound sources and the front loudspeakers are located symmetrically with respect to the listener. By manual operation of the adjusting devices a sonic image can be localized at any point in the front half plane. Continual operation of the adjusting devices causes the localized sonic image to be moved continuously within the localizable area.