US3236949A - Apparent sound source translator - Google Patents

Apparent sound source translator Download PDF

Info

Publication number
US3236949A
US3236949A US23853962A US3236949A US 3236949 A US3236949 A US 3236949A US 23853962 A US23853962 A US 23853962A US 3236949 A US3236949 A US 3236949A
Authority
US
Grant status
Grant
Patent type
Prior art keywords
signals
sound
pulse
means
loudspeakers
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
Inventor
Bishnu S Atal
Manfred R Schroeder
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nokia Bell Labs
Original Assignee
Nokia Bell Labs
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Grant date

Links

Images

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04RLOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R5/00Stereophonic arrangements
    • H04R5/04Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04SSTEREOPHONIC SYSTEMS 
    • H04S1/00Two-channel systems
    • H04S1/002Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution

Description

Feb. 22, 1966 Filed Nov. 19. 1962 3 Sheets-Sheet 1 B. s. A 74L "EA/TOPS M. R. SCHROEDER LZITTORNEV United States Patent APPARENT SOUND SOURCE TRANSLATOR Bishnu S. Atal, Murray Hill, and Manfred R. Schroeder,

Gillette, N .J assignors to Bell Telephone Laboratories,

Iyncolsporated, New York, N.Y., a corporation of New Filed Nov. 19, 1962, Ser. No. 238,539 9 Claims. (Cl. 179-1) This invention relates to the reproduction of sound, and in particular to the method of and apparatus for the production of arbitrarily located sound images with only two loudspeakers. It has for its principal object the precise control of the direction of the origin of a socalled phantom or virtual sound image in a system in which signals are radiated from two discrete points only. It is another object of the invention to simulate the effect of a number of discrete sound sources placed in different positions by the appropriate energization of two sound sources in fixed positions.

With the advent of high quality stereophonic recording and reproduction, much concern has been given to the exploitation of the spatial illusions which can be created with only two separate loud-speakers supplied with correlated signals. By suitable control of the amplitude and phase of the correlated signals the apparent origin of a sound can be placed arbitrarily at either of the two loudspeakers or at any point between them. Some widening of the sound image stage may be achieved by supplying out-of-phase correlated signals to either or both of two radiating loudspeakers. This has the effect of pushing the apparent source further away from the center line of the speaker system. However, in doing this, various undesirable effects are often produced, e.g., various in the head localizations are created. While these are not necessarily objectionable, they nevertheless are very often artificial sounding. Another way of broadening the stage involves the use of a great number of loudspeakers individually supplied with signals developed by a corresponding number of spaced microphones. Techniques of this sort yield excellent results, of course, but are economically unattractive because of the great number of individual sound channels and transducer elements required.

This invention attacks the problem of sound localization in a different way. A mathematical analysis of the sound reaching each ear from any arbitrarily placed source is utilized to develop an appropriate filter characteristic for each of two channels. Networks with the specified filter characteristic, placed in series with each of two separate loudspeakers, transform the signal radiated by each to one which will produce at both ears of a listener situated at or near the center line between the speakers, a signal identical to one that would be received by him from the arbitrarily placed source. In effect, the signals radiated from the two loudspeakers combine at the listeners ears to produce a pressure wave corresponding to a signal from an arbitrarily located source. To a first approximation, frequency independent network elements create a reasonably sharp virtual sound image. Frequency sensitive networks, however, have been found to produce very sharply defined images in any direction in the sound plane.

The two signals required for the creation of one or more arbitrarily located sound images, in accordance with the invention, contain all of the information on which the listener bases his estimate of the location of the sound. This includes the relative (frequency dependent) amplitude of signals emanating from both loudspeakers, and the times of arrival of the sound pressure waves at each of his ears. The required filter characteristic may be imparted to the two correlated signals at any point in a record or reproduce cycle. By use of the apparatus of the present invention at the reproducer station to filter signals before they are delivered to two loudspeakers, ordinary sterephonic signals may be given a wider stage width. Alternatively, the filtering may take place at a recording station, to create a pair of recorded signals that contain the required directional information. Independent playback of such a pair of signals in a twochannel system will consequently yield the desired illusion.

The invention will be fully apprehended from the following detailed descriptions of illustrative embodiments thereof taken in connection with the appended drawings in which:

FIG. 1 is a pictorial diagram illustrating the relation to one another of sound pressure waves radiated from two loudspeakers in producing an arbitrarily located sound image in accordance with the invention;

FIG. 2 is a block schematic diagram illustrating localization network apparatus suitable for use in the practice of the invention;

FIG. 3 illustrates suitable frequency characteristics for the frequency dependent amplifiers of FIG. 2 in accordance with the invention;

FIG. 4 is a block schematic diagram showing a multiple-value delay element suitable for use in the apparatus of FIG. 2;

FIG. 5 is a block schematic diagram of apparatus for processing a pair of input signals in accordance with one mode of operation of the apparatus of the invention; and

FIG. 6 is a block schematic diagram of apparatus for processing a plurality of input signals in accordance with another mode of operation of the invention.

Before entering upon a detailed description of the apparatus of the invention and of the fashion in which it operates, it is desirable to discuss certain psychoacoustic (psychological-acoustic) concepts and certain mathematical relations, some of which are implemented by the apparatus shown in the drawings.

The difference in the amplitude and time of arrival of the transients of a sound at a listeners two ears provides most of the information upon which an auditory judgment of the direction of the origin of the sound is based. Since this invention is concerned primarily with localization, the

pulse is the best stimulus for analysis. Since the short pulse encompasses all frequencies, it stands as an idealization of transients in all sounds, speech, music, noise, and the like.

The principles of the invention may thus be best described on the basis of single pulses and the manner by which they are used by a listener in determining the origin of a sound. Consider, for example, the arrangement depicted in FIG. 1. A listener 10 faces two loudspeakers 1 and 2 located at equal distances from him and at an angle :0 from the center line of his position. If a signal, e.g., a short pulse x (t), is radiated from the left speaker I, the sound pressures at the listeners left and right cars will be h "(t) and h "(t), respectively. Sound pressure wave h (t) will be the stronger of the two and will reach the listeners left ear before sound pressure Wave h "(t) reaches the right ear. Consequently, the listener will have no difficulty in correctly locating the source of pulse x (t) as originating in loudspeaker 1. Similarly, if a signal, e.g., a short pulse, x (t), is radiated from right speaker 2, the sound pressures at the listeners left and right ears will be h "(t), and h t), respectively. In this case sound pressure wave h (t) will reach the listeners right ear with greater intensity than the sound pressure wave h "(t) will reach his left ear. Moreover, it will reach his right ear before it reaches his left ear. Again no diificulty is encountered in correctly locating the origin of the sound as loudspeaker 2. Clearly then, the listener would imagine a pulse to originate at phantom loudspeaker 3 positioned at an angle go from the center line if the sound pressure wave perceived at his right ear, e.g., h "(t), reached his right car at a time, depending on the angle (p, before a wave h (t) of a somewhat lesser amplitude reached his left ear. This is precisely what his ear would hear if a sound actually originated at point 3.

It is in accordance with the present invention to provide at the listeners left and right ears, the appropriate sound pressure waves which would reach his ears from such a source of sound, 3, from the two fixed position loudspeakers 1 and 2.

To create the illusion discussed above, e.g., a pulse originating from loudspeaker 3, a single pulse is initially radiated from loudspeaker 2. It reaches the listeners right ear at a time which may arbitrarily be designated zero time and with a magnitude g=1. At a time T later, the pulse reaches his left ear with a somewhat smaller magnitude g The delay 1-,, is a function of the angular position of loudspeaker 2, namely the angle 0. So far as the right ear is concerned, the pulse could Well have originated in loudspeaker 3. However, the attenuated and delayed pulse which reaches the left ear destroys this illusion and positively establishes the source as speaker 2. Consequently, the pulse reaching the listeners left ear is canceled by a pulse radiated from speaker 1. Such a pulse must obviously reach the listeners left ear with a magnitude of inverse polarity to the magnitude of the pulse reaching his left ear from speaker 2, i.e., g and at a time T seconds later than the initial. pulse from speaker 2 reached his right ear. The illusion is not yet complete since the listener expects in his left car, a delayed and attenuated pulse from phantom loudspeaker 3. This pulse also is supplied by loudspeaker 1 at a time 'r seconds following the reference pulse. With this pulse, the necessary conditions for the establishment of an apparent source at loudspeaker 3 is complete. However, both the pulse from speaker I used to cancel the premature pulse from speaker 2, and the substitute pulse from speaker 1, reach the listeners right ear, Consequently, speaker 2 must provide the proper signals for canceling these two pulses at the right car. It will be realized that the magnitudes of these pulses are diminished and that they occur 1-,, seconds following the time of their radiation from loudspeaker 1. In like manner, the pulses from loudspeaker 2, used to cancel the unwanted pulses at the listeners right ear, are received T seconds later in diminished form at his left ear. Once again, loudspeaker 1 provides the necessary canceling signals. Each repetition has an amplitude g times that of the previous pulse and is delayed by a time 2T9.

If the above process is continued for a suificiently long time, all of the unwanted pulses are eventually canceled out by virtue of the attenuation involved in each subsequent cancellation. All that remains, therefore, at the listeners left and right ears are pulses spaced apart in time and related in amplitude as though they originated in phantom source 3.

It is thus in accordance with the present invention to energize loudspeakers 1 and 2 with signals which, when combined at the listeners ears, produce pressure waves corresponding to those from any desired direction. Simply expressed, the signals supplied to loudspeakers 1 and 2 are adjusted by means of a suitable localization network in both intensity and phase in conformity with a prescribed schedule.

From the above discussion it may be observed that if x (t) and x (t) are the inputs required to produce desired pressure responses y (t) and y (t) at the left and right ears, respectively,

where signifies convolution. If the Fourier transforms are taken for both sides of Equations 1 and 2 the following relations are obtained:

Where 10 20 1( 2( 1( and z( are the Fourier transforms of x (t), x (t), y (t), y (t), h "(t) and h (t), respectively. If Equations 3 and 4 are then solved for X (w) and X (w), x (t), and x (t) are obtained by taking the inverse Fourier transforms:

Providing that a(t) is a realizable impulse rseponse, x (t) and x 0), the required loudspeaker input signals, may be created by implementing Equations 5 and 6. For example, if it is desired to simulate a phantom sound source S at a direction (p from the center line of the listener, it is necessary only that the pressure responses 3 (2) and y (t) obtained by radiating a short pulse from the source S be appropriately specified. For simplicity, it may be assumed that the interaural delay and loss due to the sound source in any direction depend only on the angle and not on the frequency of the radiated sound. The pressure responses at the left and right ears of the listener may then be specified as:

where g,,, 7' and g, and 1-,, are the differential gains and delays produced at the two ears by sound incident from directions 0 and (,0, respectively.

Substituting for h (t), h (t), y (t) and y (t) in Equations 5 and 6 the required loudspeaker signals are obtained as follows:

Thus the signals x (t) and x (t) for the left and right loudspeakers 1 and 2, respectively, are defined such that the sound pressures at the left and right ears of the listener will be identical to those which would be developed at his left and right cars from a single source radiated from loudspeaker S. Merely by altering the parameters of the signal, the apparent direction of the sound source S may be varied within a half plane, that is, anywhere within approximately of either side of the center line between speakers 1 and 2.

The required signals x (t) and x (t) may be produced with the apparatus depicted in FIG. 2. Apparatus of this sort is termed a localization network. Considering the analysis with a single energizing pulse once again, a single pulse applied to input terminal 20 is passed by way of adder 21 directly to the positive input of subtractor 22 to form the leading pulse of output signal x (t). It thus represents the reference pulse which, in the example given above in connection with FIG. 1, denotes the first pulse received from phantom source 3 at position degrees to the right of the center line. This pulse reaches the right ear at a time 1-, later with an amplitude g Accordingly, the pulse from adder 21 is retarded 1 seconds in delay device 24 and conformed in amplitude by amplifier 25 with a gain g to that appropriate to the listeners left ear and supplied to the negative input of subtractor 26. Data concerning the relative magnitude of g may be obtained from the curves on page 224 of Speech and Hearing in Communication, H. Fletcher, D. Van Nostrand Company, Incorporated, New York, New York, 1953. The value of T, may be derived from experimental data for various values of This delayed and attenuated pulse is available at terminal 27 and, as delivered to loudspeaker 1, provides the necessary pulse at the listeners left ear for canceling the initial pulse radiated from loudspeaker 2, e.g., the initial pulse of x (t) available at output terminal 23. The correct pulse at the listeners left ear is developed by passing the pulse from adder 21 through delay device 28 proportioned to impart a delay 1,, to the signal and through amplifier 29 proportioned to attenuate the signal g, and delivering it to the positive input of subtractor 26. This component of x (t) is radiated by loudspeaker 1 and reaches the listeners ear at the correct time and with the correct magnitude to supply the necessary directional information by which the listener perceives a signal to originate at phantom source 3. Since this pulse also reaches the listeners right car, it is canceled by passing the initial pulse from adder 21 through delay device 30 proportioned with a delay 7- 4-1 and through amplifier 31 with an attenuation proportional to g,,g,,. A tandem connection of amplifiers 36 and 37, proportioned respectively with gains g, (similar to amplifier 29) and g, (similar to amplifier 25) yields the necessary product signal g g This signal is passed with negative polarity from subtractor 22 to terminal 23 and thence to loudspeaker 2. Since this signal also reaches the listeners left car, it must be canceled in the left channel. Similarly, all subsequent pulses must be reciprocally canceled indefinitely or until the magnitudes are below the threshold of perception. Since each pulse is attenuated by a factor -g,, and delayed by T when applied to the opposite loudspeaker for canceling purposes, the canceling impulse must be canceled at the first loudspeaker by a pulse of amplitude (g (g,)=g, after a delay of 1,,+1-,=27-,. Thus, each pulse must be followed by a pulse attenuated by and delayed by 2T9. This is achieved by the feedback loop portion of the network of FIG. 2. The initial pulse available at adder 21 is, in accordance with the invention, cycled through amplifier 32 with an attenuation characteristic proportional to g, and delay device 33 proportioned to have a delay time 2T9. It is then supplied to adder 21. Accordingly, every 2T9 seconds following the delivery of the initial impulse to adder 21, a new pulse is delivered to the circuits previously described. The new pulse, attenuated and delayed as compared with the reference pulse, is further attenuated and delayed in the several branch circuits as described above, so that the ultimate signals delivered to terminals 23 and 27 have the characteristics described above in Equations 11 and 12. Amplifier 32 typically includes the tandem connections of amplifiers 34 and 35, each with gain g, (to yield the requisite gain g Other arrangements for developing a signal proportioned to g, may, of course, be used.

It will be realized that, in the previous discussion, the effects of frequency have been ignored. It has been found, however, that even without frequency dependent compensation, remarkably good localization may be obtained with the apparatus of FIG. 2 with the several parameters proportioned as described. In particular, for angles less than about 60 the phantom source is quite apparent for most listeners even with frequency independent amplifiers. For angles greater than about 60, e.g., o 60, localization isless well defined since it is more strongly dependent on frequency. It is in accordance with the present invention, therefore, to adjust the frequency response of the amplifiers 25, 29, 31, and 32 in the apparatus of FIG. 2

in accordance with the particular angle (p involved, thereby to compensate for the fall-off in sharpness of the phan tom source at certain (higher) frequencies.

The frequency response of the several amplifiers may be adjusted in any conventional manner; for example, suitable filters in series with the amplifiers may be used. Alternatively, the response of the amplifiers themselves may be suitably tailored using any of the techniques well known to those skilled in the art. FIG. 3 illustrates several frequency response curves for the amplifiers for various angles. For an angle =22.5 for example, the required response is relatively flat for all amplifiers. For an angle =45, it has been found experimentally that the response of amplifiers used to adjust signals according to g, may be relatively fiat, similar to the curve g, shown for 22.5 The characteristic of amplifiers used to adjust signals to 55,, however, falls oif rapidly in frequency, as shown. Similarly, for tests have shown that the amplifiers of gain g, may retain a relatively flat response, and the response of those of gain g, should, for best directional effects, be suitably attenuated at the higher frequencies.

For improved localization at larger angles, the delays involving T must also be properly adjusted. The correct delay value may be selected, for example, from among several available delay values by means of apparatus connected in the fashion illustrated in FIG. 4. In the figure, fixed delay elements 41, 42, 43, 44 are tandemly connected to provide n difierent delay values (multiples of T) at the terminals of a multiple contact switch 45. 1- may typically be microseconds.

The localization network of FIG. 2 may thus be used as a filter to prepare suitable signals from a single one supplied to terminal 20, for energizing a pair of spaced loudspeakers in a fashion to create the necessary psychological information by which a listener imagines a sound to originate in a phantom source at any desired location in a plane. Although described on the basis of a single pulse, the desired spatial impression created as the amplifier and delay elements of the localization network are properly adjusted, will, as mentioned above, be equally well defined in the case of any real sound source, e.g., speech or music. In general, localization will be good for signals with transients. But, even for the extreme case of a source emitting a sine wave (in which case localization may be diflicult for both real and phantom sources depending on the frequency of the sine wave and the reverberation of the listening area), the phantom source created by signals developed in the localization network will be as good (sharp) as for the real source. This result is, of course, to be expected because, if a pulse is reproduced correctly at the cars, it follows from the uniqueness of Fourier transformation that all of its individual frequency components will also be correctly reproduced.

If the network is placed between a microphone or recording transducer and a pair of loudspeakers, the recorded material may be made to appear to originate at a desired phantom location. If the recorded material represents two signals of a stereophonic recording, the apparent separation aiforded by the stereophonic recording may be considerably enhanced by use of the localization networks in accordance with the present invention. The latter arrangement is illustrated in FIG. 5. In the figure, individual channel signals of a two-channel stereophonic recording are supplied respectively to input terminals 51 and 52 and, if desired, are adjusted in gain in ordinary linear amplifiers 53 and 54. The signal developed at the output of amplifier 53 is passed through localization network 55 to produce two output signals x (t) and x (t). The channel signal at the output of amplifier 54 is passed through localization network 56 to develop a pair of localized signals x (t) and x '(t). Localization networks 55 and 56 are of the construction shown in FIG. 2. As described above, the paired output signals contain the necessary clues to psychologically direct a listeners attention to a particular phantom location. The x component signals from networks 55 and 56 are combined in adder 57 and delivered to loudspeaker 1. Similarly, the x (t) signals from the networks are combined in adder 58 and delivered to loudspeaker 2. By suitably selecting the gain and delay parameters of the networks 55 and 56, any desired degree of spatial spreading of the sounds emanating from loudspeakers 1 and 2 may be secured. If network 55, for example, is adjusted to have a plus 90 characteristic and network 56 adjusted to have a minus 90 characteristic, the stereo signals, which normally would be made to appear to originate from the two loudspeaker positions or from position between them, may be made to appear to originate from points in a 180 area, i.e., from anywhere in a half plane.

On occasion it is also sometimes desirable to create at the ears of the listener sound signals, as if they actually originated at the ears, e.g., as though the listener were wearing earphones. This mode of operation has particular application to so-called artificial or quasistereo reproduction wherein crosstalk between the indivivdual channels must be minimized. Typically, different versions or modifications of a single monophonic signal are delivered independently to a listeners two ears to yield an effect which, .ambiophony or spatial spread is similar to true stereophonic reproduction. By suitably adjusting the parameters of localization networks 55 and 56, the signals radiated from loudspeakers 1 and 2 may thus be transformed as if originating at the listeners ears, i.e., the crosstalk component may be completely removed.

The localization apparatus of the invention may also be used to equalize stereophonic signals before recording so that they possess the necessary psychological directivity clues that will give rise to the phantom source illusion when the recording is subsequently reproduced with ordinary two-channel equipment. Apparatus of this sort is illustrated in FIG. 6. In the figure, a number of microphones 61-1 61-n are employed in .a studio 60 to capture sounds emanating from a variety of sources (not shown). The signals are independently amplified in amplifiers 62 and delivered to localization networks 63. Each of the networks is adjusted for a particular angle 5 associated with the corresponding microphone 61. With the arrangement shown, therefore, the signals from the microphones, which may be spaced close to one another in one plane, may be made to appear to have originated from widely spaced sources. Even if the microphones themselves are spatially oriented, as, for example, in the production of a stereophonic recording, the illusion of separation may be further enhanced appreciably by passing the signals developed through localization networks 63. The several signals x (t) developed in the networks 63 are combined and supplied by way of amplifier 64 to output terminal 65. Similarly, the x (t) signals developed at the other output of each of the localization networks are combined and supplied by way of amplifier 66 to output terminal 67. Normally, the signals which appear at terminals 65 and 67 are passed through the usual auxiliary equipment prior to recording on disc or tape. Since the recorded signals prepared in the manner described above contain the necessary directional information, reproduction of the signals on ordinary equipment will give rise to an apparent spread of the signals over a half plane area, even though only two loudspeakers are used. With either of the techniques described above, the stage width produced by two loudspeakers can be considerably increased.

The above-described arrangements are, of course, merely illustrative of the application of the principles of the invention. Numerous other arrangements may be devised by those skilled in the art without departing from the spirit and scope of the invention.

What is claimed is:

1. A two-channel sound system characterized by a broadened stage width comprising, first and second loudspeakers in spaced relation, localization network means supplied with signals from a first signal source for developing a sequence of delayed repetitions of said first signal, each replica having its magnitude adjusted according to a first schedule, localization network means supplied with signals from a second signal source for developing a sequence of delayed repetitions of said second signal, each repetition having its magnitude adjusted according to a second schedule, and means for supplying said repetitive signals from said localization networks to said first and said second loudspeakers, respectively, whereby the combined sound pressure field from said first and said second loudspeakers has prescribed phase and intensity characteristics at two different locations.

2. The sound system of claim 1 wherein said localization network means comprises: a first adding network supplied with sound signals from a source external to said network, and with periodic repetitions of said sound signals each adjusted in magnitude by a prescribed decrement; a first and second path for signals from said first adding means to first and second output terminals; the first of said paths including a second adding network, means for supplying signals from said first adding network directly to said second adding network, means for supplying signals delayed and attenuated according to a first prescribed schedule from said first adding network to said second adding network, and means for supplying the additive output of said second adding means to said first output terminal; the second of said paths including a third adding network, means for supplying signals delayed and attenuated according to a second prescribed schedule from said first adding network to said third adding network, means for supplying signals delayed and attenuated according to a third prescribed schedule from said first adding network to said third adding network, and means for supplying the additive output of said third adding means to said second output terminal.

3. A two-channel signal processing system comprising: first and second input terminals for receiving sound signals; first localization network means for developing first and second correlated signals, each including a plurality of variously delayed repetitions with prescribed intensity and phase characteristics, from signals supplied thereto from said first input terminal; second localization network means for developing first and second correlated signals, each including a plurality of variously delayed repetitions with prescribed intensity and phase characteristics, from signals supplied thereto from said second input terminal; first means for algebraically combining said first signals from said first and said second localization network means; second means for algebraically combining said second signals from said first and said second localization network means; means for delivering said algebraic combination of said first signals to a first output terminal; and means for delivering said algebraic combination of said second signals to a second output terminal.

4. A two-channel sound system comprising; first and second sources of sound signals, first and second loudspeakers in spaced relation; first localization network means for developing first and second correlated signals each including a plurality of periodically delayed repetitions with prescribed intensity and phase characteristics, from signals supplied thereto from said first source of sound signals; second localization network means for developing first and second correlated signals, each including a plurality of periodically delayed repetitions with prescribed intensity and phase characteristics, from signals supplied thereto from said second source of sound signals; first means for algebraically combining said first signals from said first and said second localization network means; second means for algebraically combining said second signals from said first and said second localization network means; means for delivering said algebraic combination of said first signals to said first loudspeaker; and means for delivering said algebraic combination of said second signals to said second loudspeaker.

5. A sound signal processing system comprising: a plurality of input terminals for the independent reception of sound signals; a plurality of localization networks, each supplied with signals from one of said input terminals, each of said localization networks including means for developing first and second trains of repetitive signals whose phase, intensity and frequency characteristics are related to each other to a prescribed degree; means for individually adjusting each of said localization networks to develop said first and said second correlated signals, respectively, according to a prescribed schedule, a different schedule being uniquely prescribed for each one of said localization networks; means for algebraically combining all of said first developed signals, means for algebraically combining all of said second developed signals; means for delivering said combination of first signals to a first output terminal; and means for delivering said combination of said second signals to a second output terminal.

6. Apparatus for creating arbitrarily located sound images comprising, a pair of loudspeakers, means for independently energizing each of said loudspeakers, localization network means associated with each of said energizing means for conforming the intensity, phase, and frequency characteristics of signals supplied thereto, in accordance with a prescribed schedule such that the resultant sound pressure waves radiated by both of said loudspeakers together combine at a location in spaced relation to said pair of loudspeakers to produce a resultant sound pressure wave whose subjective indicia indicate an origin other than in the area immediately encompassed by said pair of loudspeakers.

7. Apparatus for creating arbitrarily located sound images outside of the sector defined by a pair of loudspeakers and a point in front of and on the center line between them comprising a pair of correlated sound signals, means for independently developing from each of said signals a sequence of selectively attenuated and delayed repetitions of said signals, means for algebraically combining said first and second sequences according to a prescribed schedule to produce first and second driving signals, a pair of loudspeakers spaced apart from one another, and means for energizing each of said loudspeakers with one of said driving signals.

8. Apparatus for creating arbitrarily located sound images comprising first and second loudspeakers spaced apart from one another, a source of first and second correlated signals whose relative phases and amplitudes specify a distinct spatial location of sound origin with regard to a pair of fixed points, means for iteratively producing from said first signal a number of signal replicas spaced apart in time and individually adjusted in magnitude in accordance with a first prescribed schedule, means for iteratively producing from said second signal a number of signal replicas spaced apart in time and individually adjusted in magnitude in accordance with a second prescribed schedule, said first and said second schedules being selected with relation to one another in accordance with the spatial relation of said first and said second loudspeakers and with relation to the sound pressure wave response desired at said spatial location of sound origin, means for supplying said first signal and its adjusted replicas to said first loudspeaker, and means for supplying said second signal and its adjusted replicas to said second loudspeaker.

9. In a two-channel sound system an input terminal, means for supplying sound signals to said input terminal, means for developing from said applied signals a sequence of replicas thereof each delayed by a prescribed interval and each adjusted in intensity and phase in accordance with a first prescribed schedule, a first output terminal, means for delivering said developed signals adjusted according to said first schedule to said first output terminal, means for developing from said applied signals a sequence of replicas thereof each delayed by a prescribed interval and each adjusted in intensity and phase in accordance with a second prescribed schedule, a second output terminal, and means for delivering said developed signals adjusted according to said second schedule to said second output terminal, said first and said second schedules being selected to yield signals at said first and said second output terminals with a desired degree of phase and intensity correlation.

Burstein Stereo Amplifier controls: Electronics World, August 1959, pp. 57, 122.

Burstein Amplifiers for Stereo: October 1958, pp. 40-45.

Radio-Electronics,

ROBERT H. ROSE, Primary Examiner.

Claims (1)

1. A TWO-CHANNEL SOUND SYSTEM CHARACTERIZED BY A BROADENED STAGE WIDTH COMPRISING, FIRST AND SECOND LOUDSPEAKERS IN SPACED RELATION, LOCALIZATION NETWORK MEANS SUPPLIED WITH SIGNALS FROM A FIRST SIGNAL SOURCE FOR DEVELOPING A SEQUENCE OF DELAYED REPETITIONS OF SAID FIRST SIGNAL, EACH REPLICA HAVING ITS MAGNITUDE ADJUSTED ACCORDING TO A FIRST SCHEDULE, LOCALIZATION NETWORK MEANS SUPPLIED WITH SIGNALS FROM A SECOND SIGNAL SOURCE FOR DEVELOPING A SEQUENCE OF DELAYED REPETITIONS OF SAID SECOND SIGNAL, EACH REPETITIVE HAVING ITS MAGNITUDE ADJUSTED ACCORDING TO A SECOND SCHEDULE, AND MEANS FOR SUPPLYING SAID REPETITIVE
US3236949A 1962-11-19 1962-11-19 Apparent sound source translator Expired - Lifetime US3236949A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US3236949A US3236949A (en) 1962-11-19 1962-11-19 Apparent sound source translator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US3236949A US3236949A (en) 1962-11-19 1962-11-19 Apparent sound source translator

Publications (1)

Publication Number Publication Date
US3236949A true US3236949A (en) 1966-02-22

Family

ID=22898347

Family Applications (1)

Application Number Title Priority Date Filing Date
US3236949A Expired - Lifetime US3236949A (en) 1962-11-19 1962-11-19 Apparent sound source translator

Country Status (1)

Country Link
US (1) US3236949A (en)

Cited By (67)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3530365A (en) * 1967-09-27 1970-09-22 James A Peugh Phase shifting network for producing a phase of any value from 0 to 360
US3962543A (en) * 1973-06-22 1976-06-08 Eugen Beyer Elektrotechnische Fabrik Method and arrangement for controlling acoustical output of earphones in response to rotation of listener's head
DE2616762A1 (en) * 1975-04-17 1976-10-21 Japan Broadcasting Corp Means for spreading a sound field
FR2313807A1 (en) * 1975-06-05 1976-12-31 Sony Corp installing stereophonic
DE2716039A1 (en) * 1976-04-13 1977-10-20 Victor Company Of Japan Signal processing circuit for purposes biphonische
DE2806914A1 (en) * 1977-02-18 1978-08-24 Matsushita Electric Ind Co Ltd A sound reproduction
US4118599A (en) * 1976-02-27 1978-10-03 Victor Company Of Japan, Limited Stereophonic sound reproduction system
DE2817777A1 (en) * 1977-04-25 1978-10-26 Victor Company Of Japan Signal processing circuit for binaural signals
US4136260A (en) * 1976-05-20 1979-01-23 Trio Kabushiki Kaisha Out-of-head localized sound reproduction system for headphone
DE2818951A1 (en) * 1977-04-28 1979-02-08 Victor Company Of Japan A circuit arrangement for conversion of acoustic quadraphonic in a sound reproduction with speakers in two and four-arrangement
US4159397A (en) * 1977-05-08 1979-06-26 Victor Company Of Japan, Limited Acoustic translation of quadraphonic signals for two- and four-speaker sound reproduction
US4218585A (en) * 1979-04-05 1980-08-19 Carver R W Dimensional sound producing apparatus and method
WO1980002219A1 (en) * 1979-04-05 1980-10-16 R Carver Dimensional sound producing apparatus and method
DE3019099A1 (en) * 1979-05-18 1980-11-20 Matsushita Electric Ind Co Ltd A sound reproduction system for motor vehicle
EP0036337A2 (en) * 1980-03-19 1981-09-23 Matsushita Electric Industrial Co., Ltd. Sound reproducing system having sonic image localization networks
US4309570A (en) * 1979-04-05 1982-01-05 Carver R W Dimensional sound recording and apparatus and method for producing the same
US4317958A (en) * 1979-01-17 1982-03-02 Sony Corporation Noise reducing circuit for CTD delay line
US4356349A (en) * 1980-03-12 1982-10-26 Trod Nossel Recording Studios, Inc. Acoustic image enhancing method and apparatus
US4603429A (en) * 1979-04-05 1986-07-29 Carver R W Dimensional sound recording and apparatus and method for producing the same
US4910778A (en) * 1987-10-16 1990-03-20 Barton Geoffrey J Signal enhancement processor for stereo system
US4910779A (en) * 1987-10-15 1990-03-20 Cooper Duane H Head diffraction compensated stereo system with optimal equalization
US4975954A (en) * 1987-10-15 1990-12-04 Cooper Duane H Head diffraction compensated stereo system with optimal equalization
US5034983A (en) * 1987-10-15 1991-07-23 Cooper Duane H Head diffraction compensated stereo system
US5136651A (en) * 1987-10-15 1992-08-04 Cooper Duane H Head diffraction compensated stereo system
EP0554031A1 (en) * 1992-01-29 1993-08-04 GOVERNMENT OF THE UNITED STATES OF AMERICA as represented by THE ADMINISTRATOR OF THE NATIONAL AERONAUTICS AND SPACE ADM. Head related transfer function pseudo-stereophony
WO1994001981A2 (en) * 1992-07-06 1994-01-20 Adaptive Audio Limited Adaptive audio systems and sound reproduction systems
US5404406A (en) * 1992-11-30 1995-04-04 Victor Company Of Japan, Ltd. Method for controlling localization of sound image
EP0685986A2 (en) 1994-05-31 1995-12-06 Bose Corporation Near-field reproduction of binaurally encoded signals
US5579396A (en) * 1993-07-30 1996-11-26 Victor Company Of Japan, Ltd. Surround signal processing apparatus
US5598478A (en) * 1992-12-18 1997-01-28 Victor Company Of Japan, Ltd. Sound image localization control apparatus
US5666425A (en) * 1993-03-18 1997-09-09 Central Research Laboratories Limited Plural-channel sound processing
US5761315A (en) * 1993-07-30 1998-06-02 Victor Company Of Japan, Ltd. Surround signal processing apparatus
US5862228A (en) * 1997-02-21 1999-01-19 Dolby Laboratories Licensing Corporation Audio matrix encoding
US6009178A (en) * 1996-09-16 1999-12-28 Aureal Semiconductor, Inc. Method and apparatus for crosstalk cancellation
US6078669A (en) * 1997-07-14 2000-06-20 Euphonics, Incorporated Audio spatial localization apparatus and methods
US6111958A (en) * 1997-03-21 2000-08-29 Euphonics, Incorporated Audio spatial enhancement apparatus and methods
US6243476B1 (en) 1997-06-18 2001-06-05 Massachusetts Institute Of Technology Method and apparatus for producing binaural audio for a moving listener
US20020037084A1 (en) * 2000-09-26 2002-03-28 Isao Kakuhari Singnal processing device and recording medium
US6449368B1 (en) 1997-03-14 2002-09-10 Dolby Laboratories Licensing Corporation Multidirectional audio decoding
US20030053633A1 (en) * 1996-06-21 2003-03-20 Yamaha Corporation Three-dimensional sound reproducing apparatus and a three-dimensional sound reproduction method
US6643375B1 (en) 1993-11-25 2003-11-04 Central Research Laboratories Limited Method of processing a plural channel audio signal
US6668061B1 (en) 1998-11-18 2003-12-23 Jonathan S. Abel Crosstalk canceler
US6839438B1 (en) 1999-08-31 2005-01-04 Creative Technology, Ltd Positional audio rendering
US20050129249A1 (en) * 2001-12-18 2005-06-16 Dolby Laboratories Licensing Corporation Method for improving spatial perception in virtual surround
US6928168B2 (en) 2001-01-19 2005-08-09 Nokia Corporation Transparent stereo widening algorithm for loudspeakers
US20060068909A1 (en) * 2004-09-30 2006-03-30 Pryzby Eric M Environmental audio effects in a computerized wagering game system
US20060068908A1 (en) * 2004-09-30 2006-03-30 Pryzby Eric M Crosstalk cancellation in a wagering game system
US20060083394A1 (en) * 2004-10-14 2006-04-20 Mcgrath David S Head related transfer functions for panned stereo audio content
WO2006054270A1 (en) * 2004-11-22 2006-05-26 Bang & Olufsen A/S A method and apparatus for multichannel upmixing and downmixing
US20060115090A1 (en) * 2004-11-29 2006-06-01 Ole Kirkeby Stereo widening network for two loudspeakers
US7113609B1 (en) 1999-06-04 2006-09-26 Zoran Corporation Virtual multichannel speaker system
US7187777B1 (en) 1995-05-12 2007-03-06 Bose Corporation Sound reproducing system simulating
US7197151B1 (en) * 1998-03-17 2007-03-27 Creative Technology Ltd Method of improving 3D sound reproduction
US20070110265A1 (en) * 2005-11-14 2007-05-17 Ole Kirkeby Hand-held electronic device
US20080070685A1 (en) * 2004-09-30 2008-03-20 Pryzby Eric M Audio Object Location in a Computerized Wagering Game
DE102007026219A1 (en) 2007-06-05 2008-12-18 Carl Von Ossietzky Universität Oldenburg Audiological measuring device for generating acoustic test signals for audiological measurements
US20090086982A1 (en) * 2007-09-28 2009-04-02 Qualcomm Incorporated Crosstalk cancellation for closely spaced speakers
US20090262947A1 (en) * 2008-04-16 2009-10-22 Erlendur Karlsson Apparatus and Method for Producing 3D Audio in Systems with Closely Spaced Speakers
US20090324002A1 (en) * 2008-06-27 2009-12-31 Nokia Corporation Method and Apparatus with Display and Speaker
US20120155681A1 (en) * 2010-12-16 2012-06-21 Kenji Nakano Audio system, audio signal processing device and method, and program
US20140362996A1 (en) * 2013-05-08 2014-12-11 Max Sound Corporation Stereo soundfield expander
US20150036828A1 (en) * 2013-05-08 2015-02-05 Max Sound Corporation Internet audio software method
US20150036826A1 (en) * 2013-05-08 2015-02-05 Max Sound Corporation Stereo expander method
EP2737724A4 (en) * 2011-07-28 2015-05-06 Aliphcom Speaker with multiple independent audio streams
US9084047B2 (en) 2013-03-15 2015-07-14 Richard O'Polka Portable sound system
USD740784S1 (en) 2014-03-14 2015-10-13 Richard O'Polka Portable sound device
US10149058B2 (en) 2016-12-21 2018-12-04 Richard O'Polka Portable sound system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2114019A (en) * 1934-04-26 1938-04-12 Western Electric Co Sound reproducing system
US3094587A (en) * 1960-07-05 1963-06-18 Philco Corp Improved dual channel amplifier system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2114019A (en) * 1934-04-26 1938-04-12 Western Electric Co Sound reproducing system
US3094587A (en) * 1960-07-05 1963-06-18 Philco Corp Improved dual channel amplifier system

Cited By (93)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3530365A (en) * 1967-09-27 1970-09-22 James A Peugh Phase shifting network for producing a phase of any value from 0 to 360
US3962543A (en) * 1973-06-22 1976-06-08 Eugen Beyer Elektrotechnische Fabrik Method and arrangement for controlling acoustical output of earphones in response to rotation of listener's head
US4121059A (en) * 1975-04-17 1978-10-17 Nippon Hoso Kyokai Sound field expanding device
DE2616762A1 (en) * 1975-04-17 1976-10-21 Japan Broadcasting Corp Means for spreading a sound field
FR2313807A1 (en) * 1975-06-05 1976-12-31 Sony Corp installing stereophonic
US4118599A (en) * 1976-02-27 1978-10-03 Victor Company Of Japan, Limited Stereophonic sound reproduction system
DE2716039A1 (en) * 1976-04-13 1977-10-20 Victor Company Of Japan Signal processing circuit for purposes biphonische
US4139728A (en) * 1976-04-13 1979-02-13 Victor Company Of Japan, Ltd. Signal processing circuit
US4136260A (en) * 1976-05-20 1979-01-23 Trio Kabushiki Kaisha Out-of-head localized sound reproduction system for headphone
DE2806914A1 (en) * 1977-02-18 1978-08-24 Matsushita Electric Ind Co Ltd A sound reproduction
US4219696A (en) * 1977-02-18 1980-08-26 Matsushita Electric Industrial Co., Ltd. Sound image localization control system
DE2817777A1 (en) * 1977-04-25 1978-10-26 Victor Company Of Japan Signal processing circuit for binaural signals
DE2818951A1 (en) * 1977-04-28 1979-02-08 Victor Company Of Japan A circuit arrangement for conversion of acoustic quadraphonic in a sound reproduction with speakers in two and four-arrangement
US4159397A (en) * 1977-05-08 1979-06-26 Victor Company Of Japan, Limited Acoustic translation of quadraphonic signals for two- and four-speaker sound reproduction
US4317958A (en) * 1979-01-17 1982-03-02 Sony Corporation Noise reducing circuit for CTD delay line
US4218585A (en) * 1979-04-05 1980-08-19 Carver R W Dimensional sound producing apparatus and method
DE3041429C2 (en) * 1979-04-05 1992-03-12 Robert Weir Snohomish Wash. Us Carver
US4603429A (en) * 1979-04-05 1986-07-29 Carver R W Dimensional sound recording and apparatus and method for producing the same
US4309570A (en) * 1979-04-05 1982-01-05 Carver R W Dimensional sound recording and apparatus and method for producing the same
WO1980002219A1 (en) * 1979-04-05 1980-10-16 R Carver Dimensional sound producing apparatus and method
DE3019099A1 (en) * 1979-05-18 1980-11-20 Matsushita Electric Ind Co Ltd A sound reproduction system for motor vehicle
US4356349A (en) * 1980-03-12 1982-10-26 Trod Nossel Recording Studios, Inc. Acoustic image enhancing method and apparatus
EP0036337A3 (en) * 1980-03-19 1981-10-21 Matsushita Electric Industrial Co., Ltd Sound reproducing system having sonic image localization networks
EP0036337A2 (en) * 1980-03-19 1981-09-23 Matsushita Electric Industrial Co., Ltd. Sound reproducing system having sonic image localization networks
US4524451A (en) * 1980-03-19 1985-06-18 Matsushita Electric Industrial Co., Ltd. Sound reproduction system having sonic image localization networks
US4910779A (en) * 1987-10-15 1990-03-20 Cooper Duane H Head diffraction compensated stereo system with optimal equalization
US4975954A (en) * 1987-10-15 1990-12-04 Cooper Duane H Head diffraction compensated stereo system with optimal equalization
US5034983A (en) * 1987-10-15 1991-07-23 Cooper Duane H Head diffraction compensated stereo system
US5136651A (en) * 1987-10-15 1992-08-04 Cooper Duane H Head diffraction compensated stereo system
US4910778A (en) * 1987-10-16 1990-03-20 Barton Geoffrey J Signal enhancement processor for stereo system
EP0554031A1 (en) * 1992-01-29 1993-08-04 GOVERNMENT OF THE UNITED STATES OF AMERICA as represented by THE ADMINISTRATOR OF THE NATIONAL AERONAUTICS AND SPACE ADM. Head related transfer function pseudo-stereophony
GB2284130A (en) * 1992-07-06 1995-05-24 Adaptive Audio Ltd Adaptive audio systems and sound reproduction systems
WO1994001981A3 (en) * 1992-07-06 1994-03-17 Adaptive Audio Ltd Adaptive audio systems and sound reproduction systems
WO1994001981A2 (en) * 1992-07-06 1994-01-20 Adaptive Audio Limited Adaptive audio systems and sound reproduction systems
US5404406A (en) * 1992-11-30 1995-04-04 Victor Company Of Japan, Ltd. Method for controlling localization of sound image
US5598478A (en) * 1992-12-18 1997-01-28 Victor Company Of Japan, Ltd. Sound image localization control apparatus
US5666425A (en) * 1993-03-18 1997-09-09 Central Research Laboratories Limited Plural-channel sound processing
US5579396A (en) * 1993-07-30 1996-11-26 Victor Company Of Japan, Ltd. Surround signal processing apparatus
US5761315A (en) * 1993-07-30 1998-06-02 Victor Company Of Japan, Ltd. Surround signal processing apparatus
US6643375B1 (en) 1993-11-25 2003-11-04 Central Research Laboratories Limited Method of processing a plural channel audio signal
US5812676A (en) * 1994-05-31 1998-09-22 Bose Corporation Near-field reproduction of binaurally encoded signals
EP0685986A2 (en) 1994-05-31 1995-12-06 Bose Corporation Near-field reproduction of binaurally encoded signals
US7187777B1 (en) 1995-05-12 2007-03-06 Bose Corporation Sound reproducing system simulating
US7082201B2 (en) * 1996-06-21 2006-07-25 Yamaha Corporation Three-dimensional sound reproducing apparatus and a three-dimensional sound reproduction method
US7076068B2 (en) * 1996-06-21 2006-07-11 Yamaha Corporation Three-dimensional sound reproducing apparatus and a three-dimensional sound reproduction method
US20030086572A1 (en) * 1996-06-21 2003-05-08 Yamaha Corporation Three-dimensional sound reproducing apparatus and a three-dimensional sound reproduction method
US20030053633A1 (en) * 1996-06-21 2003-03-20 Yamaha Corporation Three-dimensional sound reproducing apparatus and a three-dimensional sound reproduction method
US6009178A (en) * 1996-09-16 1999-12-28 Aureal Semiconductor, Inc. Method and apparatus for crosstalk cancellation
US5862228A (en) * 1997-02-21 1999-01-19 Dolby Laboratories Licensing Corporation Audio matrix encoding
US6449368B1 (en) 1997-03-14 2002-09-10 Dolby Laboratories Licensing Corporation Multidirectional audio decoding
US6111958A (en) * 1997-03-21 2000-08-29 Euphonics, Incorporated Audio spatial enhancement apparatus and methods
US6243476B1 (en) 1997-06-18 2001-06-05 Massachusetts Institute Of Technology Method and apparatus for producing binaural audio for a moving listener
US6078669A (en) * 1997-07-14 2000-06-20 Euphonics, Incorporated Audio spatial localization apparatus and methods
US20070274527A1 (en) * 1997-11-18 2007-11-29 Abel Jonathan S Crosstalk Canceller
US7263193B2 (en) 1997-11-18 2007-08-28 Abel Jonathan S Crosstalk canceler
US20040179693A1 (en) * 1997-11-18 2004-09-16 Abel Jonathan S. Crosstalk canceler
US7197151B1 (en) * 1998-03-17 2007-03-27 Creative Technology Ltd Method of improving 3D sound reproduction
US6668061B1 (en) 1998-11-18 2003-12-23 Jonathan S. Abel Crosstalk canceler
US20060280323A1 (en) * 1999-06-04 2006-12-14 Neidich Michael I Virtual Multichannel Speaker System
US7113609B1 (en) 1999-06-04 2006-09-26 Zoran Corporation Virtual multichannel speaker system
US8170245B2 (en) 1999-06-04 2012-05-01 Csr Technology Inc. Virtual multichannel speaker system
US6839438B1 (en) 1999-08-31 2005-01-04 Creative Technology, Ltd Positional audio rendering
US20020037084A1 (en) * 2000-09-26 2002-03-28 Isao Kakuhari Singnal processing device and recording medium
US6928168B2 (en) 2001-01-19 2005-08-09 Nokia Corporation Transparent stereo widening algorithm for loudspeakers
US20050129249A1 (en) * 2001-12-18 2005-06-16 Dolby Laboratories Licensing Corporation Method for improving spatial perception in virtual surround
US8155323B2 (en) 2001-12-18 2012-04-10 Dolby Laboratories Licensing Corporation Method for improving spatial perception in virtual surround
US20060068908A1 (en) * 2004-09-30 2006-03-30 Pryzby Eric M Crosstalk cancellation in a wagering game system
US20080070685A1 (en) * 2004-09-30 2008-03-20 Pryzby Eric M Audio Object Location in a Computerized Wagering Game
US20060068909A1 (en) * 2004-09-30 2006-03-30 Pryzby Eric M Environmental audio effects in a computerized wagering game system
US7634092B2 (en) 2004-10-14 2009-12-15 Dolby Laboratories Licensing Corporation Head related transfer functions for panned stereo audio content
US20060083394A1 (en) * 2004-10-14 2006-04-20 Mcgrath David S Head related transfer functions for panned stereo audio content
WO2006054270A1 (en) * 2004-11-22 2006-05-26 Bang & Olufsen A/S A method and apparatus for multichannel upmixing and downmixing
US20090150163A1 (en) * 2004-11-22 2009-06-11 Geoffrey Glen Martin Method and apparatus for multichannel upmixing and downmixing
US7813933B2 (en) 2004-11-22 2010-10-12 Bang & Olufsen A/S Method and apparatus for multichannel upmixing and downmixing
US7991176B2 (en) 2004-11-29 2011-08-02 Nokia Corporation Stereo widening network for two loudspeakers
US20060115090A1 (en) * 2004-11-29 2006-06-01 Ole Kirkeby Stereo widening network for two loudspeakers
US8243967B2 (en) 2005-11-14 2012-08-14 Nokia Corporation Hand-held electronic device
US20070110265A1 (en) * 2005-11-14 2007-05-17 Ole Kirkeby Hand-held electronic device
DE102007026219A1 (en) 2007-06-05 2008-12-18 Carl Von Ossietzky Universität Oldenburg Audiological measuring device for generating acoustic test signals for audiological measurements
US20090086982A1 (en) * 2007-09-28 2009-04-02 Qualcomm Incorporated Crosstalk cancellation for closely spaced speakers
US20090262947A1 (en) * 2008-04-16 2009-10-22 Erlendur Karlsson Apparatus and Method for Producing 3D Audio in Systems with Closely Spaced Speakers
US8295498B2 (en) 2008-04-16 2012-10-23 Telefonaktiebolaget Lm Ericsson (Publ) Apparatus and method for producing 3D audio in systems with closely spaced speakers
US20090324002A1 (en) * 2008-06-27 2009-12-31 Nokia Corporation Method and Apparatus with Display and Speaker
US9485600B2 (en) * 2010-12-16 2016-11-01 Sony Corporation Audio system, audio signal processing device and method, and program
US20120155681A1 (en) * 2010-12-16 2012-06-21 Kenji Nakano Audio system, audio signal processing device and method, and program
EP2737724A4 (en) * 2011-07-28 2015-05-06 Aliphcom Speaker with multiple independent audio streams
US9560442B2 (en) 2013-03-15 2017-01-31 Richard O'Polka Portable sound system
US9084047B2 (en) 2013-03-15 2015-07-14 Richard O'Polka Portable sound system
US20150036826A1 (en) * 2013-05-08 2015-02-05 Max Sound Corporation Stereo expander method
US20150036828A1 (en) * 2013-05-08 2015-02-05 Max Sound Corporation Internet audio software method
US20140362996A1 (en) * 2013-05-08 2014-12-11 Max Sound Corporation Stereo soundfield expander
USD740784S1 (en) 2014-03-14 2015-10-13 Richard O'Polka Portable sound device
US10149058B2 (en) 2016-12-21 2018-12-04 Richard O'Polka Portable sound system

Similar Documents

Publication Publication Date Title
US3632886A (en) Quadrasonic sound system
Xie Head-related transfer function and virtual auditory display
US4219696A (en) Sound image localization control system
US7043031B2 (en) Acoustic correction apparatus
US6449368B1 (en) Multidirectional audio decoding
US5043970A (en) Sound system with source material and surround timbre response correction, specified front and surround loudspeaker directionality, and multi-loudspeaker surround
Koenig Subjective effects in binaural hearing
US3046337A (en) Stereophonic sound
US4393270A (en) Controlling perceived sound source direction
US5555306A (en) Audio signal processor providing simulated source distance control
US5970152A (en) Audio enhancement system for use in a surround sound environment
US6385320B1 (en) Surround signal processing apparatus and method
US6363155B1 (en) Process and device for mixing sound signals
US4594730A (en) Apparatus and method for enhancing the perceived sound image of a sound signal by source localization
US5708719A (en) In-home theater surround sound speaker system
US4308423A (en) Stereo image separation and perimeter enhancement
Lipshitz Stereo microphone techniques: Are the purists wrong?
US6931123B1 (en) Echo cancellation
US5822440A (en) Enhanced concert audio process utilizing a synchronized headgear system
US4893342A (en) Head diffraction compensated stereo system
US5095507A (en) Method and apparatus for generating incoherent multiples of a monaural input signal for sound image placement
US20070286427A1 (en) Front surround system and method of reproducing sound using psychoacoustic models
US20060115091A1 (en) Apparatus and method of processing multi-channel audio input signals to produce at least two channel output signals therefrom, and computer readable medium containing executable code to perform the method
US2137032A (en) Sound reproducing system
US5136651A (en) Head diffraction compensated stereo system