Abstract: A surround processor includes a time constant processing circuit for smoothing directional information signals from a detector with continuously variable time constants in order to generate one or more control voltage signals. The time constants produced by the circuit are continuously variable and responsive to both the rate of change and the amplitude of the directional information signals, such that as the difference between the controlled voltage signals and the directional information signals increases, the value of the time constants decreases to permit the control voltage signals to closely follow the directional information signals, and as the difference between the control voltage signals and the directional information signals decreases, the value of the time constants increases so that variations in the control voltage signals are smooth. Split-band processing of input audio signals to the processor is also accomplished without the necessity of placing filters directly in the audio path.

Abstract: Either the frequency of phase of an original musical sound signal is modulated, the musical sound signal is weighted, a reverberation effect is added thereto and the thus modified signal is added with the original musical sound signal.

Abstract: An artificial horizon of sound is maintained in an enclosure which is irregularly moving in a manner which may induce motion sickness of its occupant(s), by positioning sound emitters in spaced locations in the enclosure and continuously varying the sound intensity of selected emitters to create the perception of a relatively stationary sound horizon.

Abstract: An audio reproduction characteristic control device reproduces various sound fields by producing reflected sounds of a reproduced source signal. Frequency response characteristic correction parameters for correcting a frequency response characteristic which varies with a reproduction environment to a standard characteristic or other predetermined characteristic is prestored in a memory and one of these parameters is read out in accordance with a designated reproduction environment and, if necessary, additionally with a designated sound field whereby the frequency response characteristic is corrected. In another aspect of the invention, reflected sound signals for front left, front right, rear left and rear right positions of a designated sound field are generated by operating input source signals with reflected sound characteristic parameters and these reflected sound signals are added to the source signals to be propagated from four directions in a space inside of an automobile.

Abstract: A reflection sound compression apparatus extracts and compresses, most appropriately with a physical evaluation value, an impulse response of a hall, etc. which is obtained by calculation and actual experiments to reflection sounds in a number required by a sound field controller by using a learning identification method.

Abstract: A method and acoustical system for processing sound signals according to the principles of the acoustic holography of sound wave field extrapolation.

Abstract: A system for controlling the second field in auditorium having the feature that stage and audience seating areas are different acoustically, which includes a first assisted acoustics system whereby acoustical energy from the stage area is input, and then controlled acoustic energy is supplied to the audience seating area, and a second assisted acoustics which is provided independently of the first electronic acoustical augmentation system, whereby acoustical energy from the audience seating area is input, and then controlled acoustic energy is supplied to the stage area. Each assisted acoustics system includes acoustic energy input devices and acoustic energy output devices whereby a uniform rate of power decay coefficient can be effected throughout the hall, including spaces under balconies and the like. Significantly improved the degree of acoustic similarity between the stage area and audience seating area is achieved by controlling reverberation characteristics.

Abstract: An automotive audio system separates audio signals from an audio signal source into first and second components. The first component of the audio signal is sent directly to a first main amplifier and reproduced through a main speaker or speakers. On the other hand, the second component of the audio signal is sent to a second main amplifier after a predetermined delay time determined by a delay circuit. The delayed second component of the audio signal is reproduced through a auxiliary speaker or speakers after the predetermined delay time. The first and auxiliary speakers are distinct and preferably located at different points in the vehicle compartment. As a result, the directly reproduced first component and the delayed second component are reproduced through different audio sound sources. This affords the listener higher-quality audio sound and better ambience. If necessary, an echo signal generator may be added to the second component reproduction system to provide an echo effect.

Abstract: There is disclosed a sound field correcting apparatus for adding indirect sound signals to audio signals from a decoder when a steering emphasis operation is not executed in a decoder and for limiting the addition of the indirect sound signals when the steering emphasis operation has been performed by the decoder. Thus, a reproduction sound having a proper extent feeling and a movement feeling of a sound image is obtained in accordance with a scene of a video image.

Abstract: In the process of forming the effect sound for reproducing a sound field, a down-sampling part for reducing the sampling frequency of the digital signal is disposed before the step of the digital operation which becomes the central part of the forming process, by which a large amount of operation processing is carried out at a low sampling rate. With respect to the direct sound, processing such as gain adjustment is carried out without decreasing the sampling frequency. This results in a sound field control system which permits one to realize a higher quality and natural sound field control effect without significantly increasing the amount of hardware needed.

Abstract: A sound field reproduction apparatus comprises a reflectional sound signal generating circuits for generating quasi-reflectional sound signals by summing a plurality of delay signals obtained by delaying source signals in order, and amplifiers for amplifying the level of quasi-reflectional sound signals. The apparatus is characterized by a signal selecting and repeating device for alternatively repeating either the quasi-reflectional sound signals and the source signals, or source signals different from the above-described source signals. With this feature, it becomes possible to reproduce source signals other than the source signals for use in the sound field reproduction.

Abstract: Electro-acoustic system for improving the acoustic of a predetermined room, said system comprising a microphone array having a plurality of microphones and a loudspeaker array having a plurality of loudspeakers, as well as a signal processing unit, interposed between said arrays, said signal processing unit having means for generating reflections, whereby at least one of the microphones is directed in such a manner that it receives at least reflected sound from a sound source in the predetermined room and/or that at least one of the loudspeakers is directed at a reflecting surface in the predetermined room.

Abstract: A sound field correcting device provides for a natural acoustic localization of the outputs of right and left channels of an acoustic sound source. At least one of right and left channel audio signals is delayed to create a phase difference between the right and left channel audio signals, and to thus dislocate a sound in such a way that a listener not positioned equidistant between right and left channel sound sources may perceive the two channels equally.

Abstract: A digital audio signal generating apparatus suitable for the application to electronic musical instruments, sound effect generators for amusement machines and the like. This digital audio signal generating apparatus has a signal processing section and a memory used to perform a speech synthesis, wherein the signal processing section utilizes a vacant area of the memory to perform a delay processing to add a reverberation sound. Thus, the number of required memories can be reduced and the arrangement of the apparatus can be simplified.

Abstract: An electroacoustic system for acoustic enhancement of a room that includes a sound source location. The electroacoustic system includes a microphone spaced from the sound source location, an array of loudspeakers arranged in at least four interleaved banks, each bank including at least one loudspeaker, and signal processing electronics connected between the microphone and the speaker banks that includes an input channel, circuitry connecting the microphone to the input channel, a plurality of output channels corresponding in number to the number of speaker banks, circuitry connecting each output channel to a corresponding speaker bank, and at least four statistically independent time-variant reverberation units responsive to input signals from the microphone for producing output signals on the output channels for driving the several banks of speakers.

Abstract: The illusion of distinct sound sources distributed throughout the three-dimensional space containing the listener is possible using only conventional stereo playback equipment by processing monaural sound signals prior to playback on two spaced-apart transducers. A plurality of such processed signals corresponding to different sound source positions may be mixed using conventional techniques without disturbing the positions of the individual images. Although two loudspeakers are required the sound produced is not conventional stereo, however, each channel of a left/right stereo signal can be separately processed according to the invention and then combined for playback.

Abstract: An audio signal data processing system includes first and second processing devices for processing audio signal data, the first and second processing device having input and output ports of at least two channels, and a control device for controlling the operation of the first and second processing device. The input audio signal data is supplied to the input port of one channel of each of the first and second processing devices, and output data from the output port of said one channel of said first processing device is supplied to the input port of the other channel of the second processing device, and output audio signl data are obtained at each output port of both channels of the second processing device. With this arrangement, one of the cascade processing and the parallel processing can be selectively performed without using a change-over switch provided outside the system.

Abstract: An apparatus for producing an improved sound field in an acoustic space. The apparatus comprises a signal source for producing a source signal. The source signal is applied to a loudspeaker for reproduction thereof. The source signal is also applied to a reverberation circuit. The reverberation circuit includes at least two reverberation signal generators which provide different predetermined time delays to the source signal for converting it to two reverberation signals. At least one phase inverter is connected to invert at least one of the two reverberation signals before the reverberation signals are reproduced.

Abstract: A sound field switcher inputs an output sound field signal from a sound field producer. The inputted sound field signal is delayed sequentially by plural delayers, after which they are multiplied by coefficients by plural multipliers, and the multiplied results are all added by an adder. Coefficients stored in an area of a memory indicated by a coefficient counter are read out and set to the plural multipliers. The sound field switcher carries out control of the timing for switching the sound field signal produced by the sound field producer and the timing for the coefficient counter to commence counting. Assuming the time required for switching the sound field to be N sampling periods, in case of carrying out a sound field switching from a sound field A to a sound field B, a sound field switching controller issues an order to the coefficient counter so as to count up one by one from 0 to N, and on each count the coefficients stored in an area of the coefficient memory is set to the multipliers.

Abstract: An audio signal data processing system comprises an input device sequentially supplying incoming audio signal data, a data memory control device writing and reading-out the audio signal data into and from a data memory, a delay memory control device sequentially reading-out the audio signal data from the data memory and storing the data into a delay memory and sequentially reading-out the audio signal data from the delay memory and writing the data into the data memory, an arithmetic device multiplying predetermined coefficient data by the audio signal data having been read-out by the delay memory control device and written into the data memory and summing up results of the multiplication.

Abstract: A reverberation circuit comprises an amplifier, attenuation circuit, a feedback component, and a delay circuit. The amplifier, delay circuit, and feedback component form a feedback loop. The amplifier amplifies an input signal supplied to an input terminal and outputs an amplified signal to the delay circuit. The output of the delay circuit is fed through a feedback component back to the amplifier. The feedback component controllably varies the feedback amount of the delayed signal to the amplifier in accordance with the desired depth of reverberation. An attenuation circuit is placed in the feedback loop, or before or after the feedback loop. The attenuation circuit selectively attenuates the level of specific frequency component of a signal passing therethrough whose frequency may be different depending on the depth of reverberation or feedback amount.

Abstract: An input waveform signal is converted in an A/D converter into a digital signal to be written in a waveform memory under control of a tone generation control unit. The written digital signal is read out from the waveform memory with a designated delay time. The input waveform signal and the digital signal read out from the waveform memory are converted in a D/A converter into analog signals which are fed through VCFs and VCAs so as to be sounded. Further, in the above arrangement the timbre and tone volume controls are done independently for the individual waveform read/write channels through VCFs 12a to 12d and VCAs 13a to 13d. Thus, it is possible to obtain a further effected sound.

Abstract: A sound reproducing apparatus is capable of reproducing a stereo or a voice signal and adding thereto effect sounds, such as an initial reflected sound, and reechoed sound during the reproducing. Each of the effect sounds is added with a delay time depending on a change of the sound source signal. To obtain the delay time, the sound source signal is converted into a three-value signal, and then the time in which the auto-correlation of the three-value signal decreases to a predetermined value is determined. Thus the effect sounds can be added automatically with a desired delay time due to the sound source signal. Therefore manual adjustments are unnecessary, and the circuit structures of the entire apparatus can be simplified.

Abstract: A control circuit for controlling reproduced tone characteristics capable of prestoring sound field characteristics to be imparted to a reproduced tone and frequency characteristics of the reproduced tone in combination and reproducing these characteristics simultaneously comprises a sound field characteristics imparting circuit responsive to an input tone signal for producing a sound field effect signal thereby to impart sound field characteristics to a reproduced tone, a frequency characteristics control circuit receiving the input tone signal and outputting the same after controlling frequency characteristics thereof, a memory for storing parameters for setting sound field characteristics to be imparted to the reproduced tone and parameters for controlling frequency characteristics of the input tone signal in combination, and a control circuit for reading out the parameters for setting sound field characteristics and the parameters for controlling frequency characteristics of the input tone signal simultan

Abstract: A reverberation imparting device for electro-acoustically enhancing reverberation in acoustic space comprises a microphone disposed in the acoustic space, a loudspeaker disposed in the acoustic space for diffusing the sound picked up by the microphone, and feedback means comprising a signal processing circuit for electrically processing an electric signal corresponding to the sound picked up by the microphone, an output of the signal processing circuit being supplied to the loudspeaker. The microphone, feedback means and loudspeaker form a feedback loop. The signal processing circuit comprises a circuit for subjecting impulse responses of finite length to a convolution operation. Time axis of reflected sounds is extended and extension of reverberation time thereby is realized without depending upon loop gain. Density of reflected sounds is increased by subjecting impulse responses of finite length to a convolution operation whereby separation of reflected sounds is prevented.

Abstract: An apparatus for changing a sound field, comprising at least two signal processing means, which can smoothly and continuously switch a sound field into an arbitrary sound field without a break of signals by alternately switching one of the signal processing means into the other.

Abstract: A variable delay circuit for delaying an input signal and being capable of changing length of this delay is provided and various modulation effects are imparted by this delay. When change in the delay length has been designated, a decay envelope is imparted to a delay output tone signal corresponding to the delay length before the change and then a rise envelope is imparted to a delay output signal corresponding to the delay length after the change. Generation of a click noise during the change in the delay length thereby is prevented. Alternatively, when the delay length is to be changed, a decay envelope is imparted to a delay output signal corresponding to the delay length before the change and, simultaneously, a rise envelope is imparted to a delay output tone signal corresponding to the delay length after the delay and the two signals are combined.

Abstract: Each time sampling clock CK is input, a controller controls respective circuits, and performs various arithmetic operations of data stored in tone color parameter memories, and time-divisionally performs sound effect addition and changing of tone color parameters.

Abstract: Disclosed is a signal processor formed using digital waveguide networks. The digital waveguide networks have signal scattering junctions. A junction connects two waveguide sections together or terminates a waveguide. The junctions are constructed from conventional digital components such as multipliers, adders, and delay elements. The signal processor of the present invention is typically used for digital reverberation and for synthesis of reed, string or other instruments.

Abstract: A sound field correcting system for correcting for mulitpath frequency-characteristic distortion in an acoustic reproducing system. In one embodiment, the level and delay of an original signal are adjusted and superposed on the original signal so as to obtain a signal which, when reproduced by a loudspeaker, yields a sound pattern at a listening point having a flat frequency characteristic. The delay adjustment is effected in accordance with a difference between the travel distances of direct and reflected sound waves to the listening point.

Abstract: A reverb generator comprises a delay circuit for delaying an input audio signal, a feed back path connecting an output port of the delay circuit to its input port, and a phase shifter connected in series to the delay circuit. The phase shifter produces a dispersion in the spectrum of the input audio signal in accordance with frequency dependent delay characteristic in such a manner that the delay time is large in a low frequency range and small in a higher frequency range. By including the phase shifter in the feed back path, one can obtain an output audio signal having a spectrum which is repeatedly subjected to dispersion, thus simulating the effect of dispersion due to the multiple reflections taking place in an actual concert hall.

Abstract: A system for reproducing stereophonic sound signals to create an appropriate audio sound ambience in various compartments having different reverberation characteristics. The system includes a right-hand loudspeaker for producing a right-channel sound signal, left-hand loudspeaker for producing a left-channel sound signal, and a center loudspeaker for producing a signal derived from a combination of right and left signals. The center loudspeaker generates a sound output of a signal having a predetermined lag time relative to that of the right- and left-speakers to create the suitable audio ambience effect for a listener in accordance with the reverberation characteristics of the compartment.

Abstract: A tone signal applied from outside is sampled by a tone sampling device and the sampled waveshape data is written into a memory. During this writing operation and in parallel with the writing operation, a zero crossing point of the waveshape in terms of the sample data of the tone signal is detected. A final address detection circuit stores, each time a zero cross has been detected, a write address of the waveshape sample data with respect to the memory. Address data which is stored in the final address detection circuit when the writing of the waveshape sample data in the memory has been completed is detected as a final address of the sampled waveshape data. The waveshape data in the memory is read out either in a forward direction in a reverse direction using this final address as a start point or an end point and a tone signal corresponding to the sampled waveshape data is sounded. Such address constituting the start point or end point of reading, i.e.

Abstract: An audio signal processing apparatus for digitally processing input audio signals according to the contents of a program for creating a given sound field. A basic program for creating a specific sound field is read from a first memory. The contents of the basic program are modified as required. The modified program is assigned thereto information identifying the basic program. The modified program as well as the identification information is stored in a second memory. When the modified program is read from the second memory, the information identifying that program is displayed first. After a predetermined time, the information identifying the basic program on which the modified program is based is displayed, replacing the previously displayed identification information.

Abstract: A multi-channel reproducing system comprises main speakers for sounding an input audio signal as a main channel audio signal, a phase shifter supplied with the input audio signal for shifting a phase thereof, and sub-speakers supplied with an output signal from the phase shifter as a sub-channel audio signal for sounding the sub-channel audio signal. The phase shifter has a frequency versus delay time characteristic in which a delay becomes large as the frequency decreases and small as the frequency increases.

Abstract: An artificial, three dimensional auditory display which artificially imparts localization cues to a multifrequency component electronic signal which corresponds to a sound source. The cues imparted are a front to back cue in the form of attenuation and boosting of certain frequency components of the signal, an elevational cue in the form of severe attenuation of a selected frequency component, i.e. variable notch filtering, an azimuth cue by means of splitting the signal into two signals and delaying one of them by a selected amount which is not greater than 0.67 milliseconds, an out of head localization cue by introducing delayed signals corresponding to early reflections of the original signal, an environment cue by introducing reverberations and a depth cue by selectively amplitude scaling the primary signal and the early reflection and reverberation signals.

Abstract: A reverberation imparting device comprises a delay memory storing input signal data at a predetermined sampling period and producing a delay signal corresponding to time interval between writing of the input signal data and reading thereof, a plurality of address each adding delay signals read out from the delay memory, and an output section for delivering out an output of each of the adders as a reverberation signal. The delay signals are divided into groups and processed on the group basis. This simplifies the construction of the device and facilitates setting and changing of the reverberation characteristics.

Abstract: A reverberating platform structure usable as an exercise floor or, depending upon the configuration thereof, for the support of people or objects thereon wherein the platform is supported by an anchor structure above a foundation such that there is an open space between the foundation and the undersurface of the platform. The anchor structure may be essentially flexible so as to provide a giving or flexible structure to the platform for a person to exercise, dance, or otherwise move thereon. An agitator assembly primarily in the form of a plurality of speakers are disposed within the space immediately adjacent to the space slightly from the undersurface of the supporting platform wherein activation of the speakers causes vibration to be communicated directly to the platform but wherein the platform is further structured not to generate specific sounds therefrom so as to be considered part of the speaker system itself.

Abstract: A method and apparatus for processing audio signals utilizing reverberation in combination with directional cues to capture both the temporal and spatial dimensions of a three-dimensional natural reverberant environment. Reverberant streams are generated and directionalized to simulate a selected model environment utilizing pinna cues and other directional cues to simulate reflected sound from various spatial regions of the model environment.

Abstract: In a reverberation tone generating apparatus a digital memory device is used as a delay element. Amplitude data obtained by sampling an input musical tone at a predetermined period are sequentially stored in the digital memory device. The readout of the amplitude data stored before a desired delay time is equal to the readout of the data regarding the input musical tone delayed the desired delay time. By imparting the desired reverberation characteristics to the delayed amplitude data, reverberation tone of the input musical tone is produced. In a modified embodiment, an input musical tone is divided into a plurality of frequency bands and different reverberation characteristics are added to the divided input musical tones respectively.

Abstract: An improved system is disclosed for generating a signal encoded with stereophonic information and adapted to be used with a monophonic signal to synthesize stereophonic reproduction. The system includes means for generating the encoded signal as a function of at least a portion of the program information of a monophonic input signal so as to control the amount of stereophonic spread provided during stereophonic reproduction provided by the encoded signal and a monophonic signal derived from the monophonic input signal. The system is particularly adapted for use in the transmission and/or reception of stereophonic television signals.

Abstract: A reverberation imparting device comprises a prememory storing an input signal, a level detection circuit responsive to data stored in the prememory for detecting presence or absence of the input signal, a data memory storing a delayed input signal delivered out of the prememory, a fixed type convolution operation circuit for producing a reverberation signal with respect to the data stored in the prememory by using an initial portion of parameters of a reflected sound, an adaptive type convolution operation circuit for producing a reverberation signal with respect to data stored in the data memory by using a plurality of parameters of more significant bits among the remaining portion of the parameters of the reflected sound, and an adder for adding outputs of the fixed type and adaptive type convolution circuits and delivering out the result of addition as a reverberation signal.

Abstract: An automotive audio system separates audio signals from an audio signal source into first and second components. The first component of the audio signal is sent directly to a first main amplifier through a first audio signal path and reproduced through a main speaker or speakers. On the other hand, the second component of the audio signal is sent to a second main amplifier through a second audio signal path. An echo system is provided with the second audio signal path, which echo system induces echos in the audio sound to be reproduced through the second main amplifier. The echo system is associated with a discriminator circuit which receives an audio signal output from the audio signal source and derives an echo system control signal on the basis of the audio signal. The echo signal control signal is fed to the echo system for controlling operation of the echo system.

Abstract: A preamplifier adapted to receive audio frequency electrical signals generated by a musical instrument for providing controlled output signals therefrom having selected distortion and harmonic signal content is shown wherein the preamplifier includes an amplifier for amplifying audio frequency electrical signals generated by the musical instrument, a first electrical signal processing channel operatively coupled to the amplifier for receiving the amplified audio frequency electrical signals and for producing in response thereto a first controlled output signal wherein the first electrical signal processing channel includes a plurality of selectively interconnectable signal processing circuits at least one of which is capable of at least one of selectively amplifying, distorting and adding preselected harmonic content to the first controlled output signal, a second electrical processing channel operatively coupled to the amplifier for receiving the amplified audio electrical signals and for producing response

Abstract: A device for forming a stereophonic sound field in a simulated fashion constructed in the form of a monophonic-to-stereophonic conversion circuit in which a monophonic signal is applied to cascade-connected twin-T circuits having different null point frequencies and an output signal of the twin-T circuits is provided as one stereophonic channel signal whereas an output obtained by substracting the one stereophonic channel signal from the monophonic signal is provided as the other stereophonic channel signal. A low-frequency signal attenuating resistor and a high-frequency signal attenuating filter are provided on the output side of the twin-T circuits to equalize peak values in frequency characteristics of the output signal of the twin-T circuits and thus obtained signal is amplified to be equalized in peak level to the monophonic signal and thereafter is applied to a subtractor together with the monophonic signal.

Abstract: An acoustic system comprising an input transducer connected by a first severable path to the input of reverberation means for producing reverberation of the required decay rate of the sound field perceived by the microphone, an output transducer connected by a second severable path to the output of the reverberation means, and detection means which analyzes the status of the sound field or any discrete frequency domain within the sound field and which operates both to connect the input transducer over the first path to the reverberation means and to secure connection of the reverberation means to the output transducer over the second path when the status of the sound field or the discrete frequency domain is analyzed by the detection means as either rising or constant and, conversely, both to sever the connection of the input transducer over the first path to the reverberation means and to connect the reverberation means to the output transducer over the second path when the status of the sound field or the d

Abstract: The present invention relates to a system for generating within a relatively small enclosed space a sound field corresponding to that in a relatively large enclosed space having specific acoustic characteristics, said system including an input unit adapted to receive at least one primary electric audio signal, the output of which is connected to the input of a signal processing unit having a number (N) of secondary channels, each provided with signal processing means with selectable delay time and selectable gain constant, the N outputs of said channels being intended to produce N secondary electric audio signals, each to be supplied to one of N secondary loudspeaker units placed in said relatively small enclosed space in preselected positions. The invention proposes a system of a kind as mentioned above and comprising a programmable memory for storing parameter groups representative of a number of various relatively large enclosed spaces, i.e.

Abstract: Tone signals from plural keyboard systems are supplied to an effect imparting circuit via a distribution circuit. The effect imparting circuit comprises plural effect imparting channels and the device can impart a tone effect independently to a tone signal provided to each of the effect imparting channels. The distribution circuit distributes tone signals from the respective keyboard systems to any one or more of the effect imparting channels. An effect selection device is provided for selecting tone effects for the respective keyboard systems and an effect assignment device is also provided for assigning the effects selected in the respective keyboard systems to any of the effect imparting channels according to the selection by this effect selection device. The distribution circuit delivers the respective tone signals to the proper effect imparting channels respectively as controlled by the effect selection and the effect assignment.

Abstract: A voice activated echo generator employs digital voice recording technology to digitize several spoken words of audio using low-cost encoding techniques. The audio information is stored in dynamic memory and is played back by reconverting the data back from its digitized form to audio, which then drives a loudspeaker. The echo generator has many design parameters which can be varied, such as, duration of recorded speech, voice actuation sensitivity, number of playback repetitions, speech quality, playback speed, playback pitch, and playback volume. For a toy, an input speech threshold initiates a distinct record interval followed by a substantially immediate and automatic playback interval during which the echo is generated without the problem of acoustic feedback.

Abstract: An apparatus for generating a pseudo-stereo signal comprises at least two signal channels (3, 4), each signal channel (3) comprising a delay line (7) of which an output is fed back to the input (via g.sub.2). The delay lines (7, 8) have tappings (12, 13 and 14, 15 respectively). The tappings (12, 14 and 13, 15 respectively) are coupled to inputs of two signal-combination units (18 and 19, respectively) whose outputs (20, 21) are coupled to two output terminals (22, 23) to supply the pseudo-stereo signal (FIG. 1).