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: A stereo expansion circuit has right and left amplifying channels for providing expanded stereo signals. A selection device comprises a switch cross coupling the signal channels for providing expanded stereo when the switch is closed. Circuitry is provided for preventing the switching control signal from being coupled to the signal channels. More specifically, a version of a signal coupled between the signal channels through the conduction channel of the switch is applied to the control input of the switch to inhibit the control signal from being coupled to the conduction channel. Such an arrangement is particularly advantageous when the switch comprises a J-FET.

Abstract: A system for the multichannel reproduction of sound in which a plurality of loudspeakers connectable to a surround sound processor is disclosed. Circuits for adapting the processor to provide left and right side output signals are also disclosed. Left and right side dual loudspeakers are disclosed wherein each dual loudspeaker contains two independent drivers, one facing the front and the other the rear of the listening area, the front-facing drivers being connectable to the left and right side output signals and the rear-facing drivers being connectable to the corresponding left and right rear output signals of the processor.

Abstract: A sound reproducer is disclosed for a Hi-vision 3-1 sound system composed of an audio signal decoding unit coupled with an AV amplifier, which amplifier has a surround processor and is originally arranged for reproducing surrounding sounds from two-channel stereophonic audio signals of the Dolby.RTM. surround system, wherein volume controllers for controlling right and left rear Hi-vision audio signals of monaural and a center front Hi-vision audio signal, and first through third switching circuits for selecting outputs of the audio signal decoding units, are provided in case of reproducing sounds of the Hi-vision 3-1 sound system, or outputs of the surround processor, in case of reproducing sounds of the two-channel sound surround system, for providing the acoustic balance of the audio signals when the first through third switching circuits are switched to reproduce the sounds of the Hi-vision 3-1 sound system.

Abstract: Control codes for controlling processing of an audio signal by a sound field variation circuit to produce desired sound fields are recorded on a monaural track of a video tape concurrent with recording of video and audio signals, and can thereby be subsequently played back for producing sound fields which are respectively synchronized with video images.

Abstract: A surround processor adapted to apply a stereo surround processing and a monaural surround processing to audio input signals of two channels to provide surround processed outputs, wherein a stereo/monaural discrimination output based on inputted audio signals of two channels is caused to have a predetermined time constant to provide a mixture ratio control signal to change a mixture ratio between a stereo surround processing output signal and a monaural surround processing output signal, to thereby discriminate whether an input signal is a stereo signal or a monaural signal and to automatically carry out switching between the surround processing output. The time constant prevents switching between the stereo surround processing state and the monaural surround processing state from being suddenly conducted.

Abstract: An FM stereo receiver for receiving FM stereo broadcast signals includes a pro-logic surround system in which the left stereo signal, a right stereo signal, a stereo sum signal and a stereo difference signal are selectively emphasized. Also includes a noise signal detector for detecting the noise signal in the received signal, and a device for disabling the pro-logic surround system when the noise signal is detected.

Abstract: A sound field control device is capable of producing a sound field effect tone which has a tonal effect providing a listener with a feeling of presence and includes a sound field effect tone generation circuit for generating a sound field effect tone on the basis of sound field information supplied from a source. The sound field effect tone is sounded simultaneously with reproduction of the source signal and a reproduced sound field produced on the basis of the source signal is controlled by this sound field effect tone. In one aspect of the invention, the sound field effect tone generation circuit includes a convolution operation circuit which subjects a signal derived from left and right signals from the source signal to convolution operation with sound field data derived on the basis of the sound field information from the source signal.

Abstract: Disclose is a four-channel surround-sound generator capable of generating a first surround-sound in phase to a basic channel reproduction sound and a second surround-sound out of phase thereto, by employing a channel-switching control circuit and a channel-sound delaying circuit.

Abstract: A television receiver includes a volume control circuit (4) for controlling levels of sound signals corresponding to a left channel, a right channel, a center channel and a surround channel and speakers (6 to 10) corresponding to these channels. The television receiver further comprises a test tone circuit (11; 18), a microcomputer (14) and a character display circuit (16). The test tone circuit (11; 18) supplies a test tone of a prescribed frequency sequentially to the speakers (6 to 10) through the volume control circuit (4). The microcomputer (14) provides a command to the character display circuit (16) so that a CRT 17) displays which speaker is currently supplied with the test tone as well as volume levels of the respective speakers.

Abstract: A signal processing circuit in a playback system, according to the present invention, comprises a storage device for temporarily storing a digital signal output from a digital output stage of the playback system and a controller for controlling the data stored in the storage device in such a manner that the data is sent out from the storage means with a time difference.

Abstract: A stereo processing system which comprises a left channel and a right channel; a filter in each of the channels for separating an audio signal into a plurality of bands; a phase-shift/delay circuit in each of the channels for receiving a portion of the output of the corresponding filter and phase-shifting and delaying the received signal for each of the separated bands; a pair of input/output circuits interconnecting the left channel and the right channel for exchanging the signals between the two phase-shift/delay circuits for mixing the signal received from the filter of the left channel with the signal received from the phase-shift/delay circuit of the right channel in the phase-shift/delay circuit of the left channel and vice versa; a mixing circuit in each of the channels for mixing the signal received from the output of the corresponding filter with the output of the corresponding phase-shift/delay circuit; and a phase detector/delay circuit coupled to the outputs of the mixing circuits of the left and

Abstract: An electronic switching system is presented for use by consumers. Inputs are connected to the circuit which detect which input is producing a signal. The circuit then allows that signal to pass through to be reproduced on output speakers. If both of two inputs are "on," producing two signals, the system toggles between the signals thus reproducing a toggling signal at the speakers. The system may also be adapted to accommodate three or more input signals which would then produce either one output if only one is "on" or a toggling output between those inputs that are "on.

Abstract: A sound field control apparatus is provided with a memory storing first and second sound field data; a first digital sound processor convoluting the first sound field data to a sum signal of two channel stereophonic input signals to produce a first initial reflection sound signal group; and a second digital sound processor convoluting the second sound field data to a difference signal of the two channel stereophonic input signals to produce a second initial reflection sound signal group. Thus, sound field reproduction which is richer in flexibility and change can be materialized. Sound fields created by the sound field data supplied to each digital sound processor can independently be changed and thereby it is possible to cause the sound field reproduction to be widely varied as a whole.

Abstract: Sound projecting apparatus employs a microcomputer to pan a musical performance automatically, according to a preset program, and to display the instantaneous location of the apparent sound source by means of an array of lights.

Abstract: An input musical tone signal is amplified by a first VCA and then supplied to second and third VCAs. The second and third VCAs are controlled by sine-wave signals which have a 180.degree.-phase difference. Musical tone signals, which have been so controlled that a pan-pot may move right and left, are supplied to right and left loudspeakers. The first VCA is controlled by a sine-wave signal whose phase is different by 90.degree. from the phases of the signals supplied to the second and third VCAs. The volume of a composite musical tone made up of the tones generated by the loudspeakers is thereby controlled, thus also moving the pan-pot to the front and rearward.

Abstract: A multichannel reproduction system for use with a source providing left (L) and (R) signals includes circuitry for developing difference signals L-R and R-L which are delivered to individual ones of four speakers arranged in a specific T-configuration. The L and R signals are delivered to the left and right speakers in the T-configuration, respectively, while the top speaker in the "T" between the left and right speakers receives the L-R signal and the bottom speaker at the foot of the "T" receives the R-L signal. Alternately, the L-R signal is delivered to the top speaker and the R-L signal to the bottom speaker.

Abstract: A sound recording having right and left information channels to drive right and left speakers, respectively. The right information channel has a left main stereo component having a pattern corresponding and similar to a left stereo input signal. In addition, it has a right to left compensating component having a pattern which corresponds to an inverted and delayed pattern of a right stereo input signal. In like manner, the right channel has a right main stereo component having a pattern corresponding and similar to the right stereo input signal. It also has a left to right compensating component having a pattern which corresponds to an inverted and delayed pattern of the left stereo input signal. The effect is that the main stereo components travelling to the nearest ear of a listener are not diminished substantially, while the main stereo components travelling to the further ear are diminished. The effect is a highly dimentionalized sound pattern.

Abstract: This invention relates to an apparatus and to a method for enhancing the perceived sound image of a stereophonic, audio reproduction system whose inputs are a right and a left signal channel by decoding the right and left signal channels into a modified right, a modified left and a center signal channels. Signal information common to the original right and left signal channels is removed within a specified bandwith to produce the modified right and modified left signal channels. The original right and left signal channels are combined and frequencies below a predetermined cutoff frequency are attenuated to produce the center signal channel.

Abstract: In providing stereophonic reproduction of sound in the passenger space of a motor vehicle, a pair of speakers are located at the opposite ends of the dashboard ahead of the driver, one for reproducing the left signal of a sound recording and the other for reproducing the right signal. In addition, at least one of a summation signal made up of the left signal and the right signal is provided from a speaker located at the dashboard between the pair of speakers, and a differential signal, made up of the left signal and the right signal, is directed forwardly from the rear of the passenger space. Further, the differential signal can be made up only of middle and lower frequencies supplied to one rear speaker with another rear speaker turned 90.degree. relative to the one rear speaker and radiating the differential signal to opposite sides of the passenger space. An electronic delay can be incorporated into the rear speakers.

Abstract: A signal decoding system for use in a quadraphonic type sound reproducing system is disclosed. In accordance with one aspect of the invention, a multiband expander is used to control the steering of the four information signals decoded from the two input signals. In accordance with another aspect of the invention, the difference between the rear and front signals is used to enhance virtual sound images to one side of a listener.

Abstract: A stereophonic sound producing apparatus employs four speakers, a background-sound input signal and input-sound signals, to provide an on-the-spot "live action" feeling. The sounds are combined and varied such that a sound such as an artillery shell has a simulated sound and an aurally simulated movement discernible to a human ear. Mixers and attenuators are used, so that a digital "1" or "0" signal serves to operate the on-the-spot "live action" sound effects. A cockpit is provided, together with a video display. A video signal and/or background sound signal is provided by a digitally encoded disk.

Abstract: An ambience simulating apparatus having a mixer for combining a plurality of at least two electrical analog signal representations of audio signals into a single analog signal, digitizing circuits for digitizing said single analog signal, a memory for storing the digital representation of said analog signal, and circuitry for selectively collecting, attenuating, and combining portions of the data stored in the memory, whereby a signal can be produced which represents the combination of a plurality of delayed and attenuated audio signals which when reproduced as an audio signal in combination with the reproduction of the audio signals from said plurality of electrical analog signals, creates a fullness of sound referred to as ambience.

Abstract: A stereo or two channel electronic reverberation device is disclosed comprising an analog delay device which receives audio signals and provides delayed output signals at a plurality of outputs, with the time delay period of each output being different from the delay period of other outputs. Two summing devices each receive inputs from different combinations of the analog delay device outputs to provide two different signals having different reverb components. An additional output delay device is also provided which receives the last output from the analog delay device, delays this signal a time period substantially greater than the time period between any two adjacent analog delay device outputs, and provides this substantially greater delayed signal to only one of said summing devices.

Abstract: Enhanced pyschoacoustic imagery is achieved in an audio signal processing circuit for processing plural channels of related audio signals. Asymmetric bi-directional audio signal cross-feed is established between first and second audio signal processing channels, for example. The cross-fed signal components are combined in an out-of-phase relationship with respect to related audio signals already passing through a given channel. The asymmetry is designed so as to complement the asymmetry which is believed to be present in a listener's brain processing of perceived acoustic signals due to the naturally occurring left or right half brain dominance of the listener. In other embodiments both symmetric and asymmetric, cross-feeding is limited to signal components below a predetermined frequency.

Abstract: An equalizer apparatus for audio equipment capable of selecting between a 2-speaker system and a 4-speaker system, including a display device indicating proper operation of the control knobs of the equalizer. The display device includes a first illuminable element of a first color for indicating operation of one channel of stereophonic sound reproduction, a second illuminable element of a second color for indicating operation of the other channel of stereophonically reproduced sound, and color coded means corresponding to said first and second colors for indicating which of the control knobs produce data signals for the first channel and which of the control knobs produce data signals for the second channel. Further, the color coded means may indicate which of the control knobs produce data signals for each of the divided frequencies of the respective channels during operation of the audio equipment in the manner simulating quadriphonic sound.