EP0664660A2 - Audio signal reproducing apparatus - Google Patents
Audio signal reproducing apparatus Download PDFInfo
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- EP0664660A2 EP0664660A2 EP95104929A EP95104929A EP0664660A2 EP 0664660 A2 EP0664660 A2 EP 0664660A2 EP 95104929 A EP95104929 A EP 95104929A EP 95104929 A EP95104929 A EP 95104929A EP 0664660 A2 EP0664660 A2 EP 0664660A2
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- Prior art keywords
- transfer characteristics
- audio signal
- signal
- head
- listener
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R5/00—Stereophonic arrangements
- H04R5/033—Headphones for stereophonic communication
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04S—STEREOPHONIC SYSTEMS
- H04S1/00—Two-channel systems
- H04S1/002—Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution
- H04S1/005—For headphones
Abstract
Description
- The present invention relates to an audio signal binaural reproducing apparatus for reproducing audio signals by means of headphones.
- A binaural reproducing method has heretofore been known as an approach for providing better direction sensation of sound image or outside head localization sensation when audio signals are reproduced by headphones fitted to the head of a listener so that a pair of headphones are located in the vicinity of both ears.
- An audio reproducing system adopting this binaural system preliminarily applies a given signal processing to the audio signals reproduced by headphones as is described in, for example, specification of Japanese Patent Publication Sho 53-283.
- The direction sensation of sound image and outside head localization sensation and the like depend upon the differences in volumes, times and phases of sounds listened by left and right ears.
- The signal processing aims at causing in an audio output reproduced by the headphones, audio effects equivalent to those caused by the difference in distances between sound sources, that is, speaker systems and right and left ears of a listener and reflections and diffractions in the vicinity of the head of the listener when audio reproducing is performed, for example, by speaker systems remote from the listener. Such a signal processing is performed by convolution-integrating left and right ear audio signals with impulse responses corresponding to the above-mentioned audio effects.
- Since the absolute position of the sound image is not changed even if the listener moves or turns his or her head when audio reproducing is performed by speaker systems remote from the listener, the relative direction and position of the sound image that the listener senses are changed. In contrast to this, since the headphones is turned together with the listeners head if the listener turns his or her head when audio reproducing is performed by a binaural method using headphones, the relative direction and position of the sound image which the listener senses are not changed.
- If binaural reproducing is performed by using headphones in such a manner, a sound image is created in the head of a listener due to differences in displacement of the sound image relative to a change in direction of the listener's head. Therefore, it is difficult to locate the sound image in front of the listener. Furthermore, the front sound image has a tendency to lift up.
- Accordingly, an audio signal reproducing system which detects a change in the direction of the listener's head and changes the modes of the signal processing based upon a result of the detection for providing a good front localization sensation in headphones has heretofore been proposed as is disclosed in Japanese Unexamined Patent Publication No. Sho 42-227 and Japanese Examined Patent Publication No. 54-19242. In such an audio signal reproducing system, a direction detecting device such as gyrocompass and magnetic needle is provided on the head of the listener. A level adjusting circuit and a delay circuit and the like for processing the audio signals are controlled based upon a result of detection from the direction detecting device so that a sound image sensation which is similar to that of the audio reproducing using speaker systems remote from the listener is obtained.
- In the prior art binaural reproducing system in which headphones are provided with a direction detecting device comprising a gyrocompass, an excellent sound image can be obtained by controlling the content of the signal processing which is applied to the audio signals depending upon changes in direction of the listener's head.
- In order to control the content of the signal processing applied to the audio signals depending upon a change in direction of the listener's head, it is necessary to preliminarily measure the impulse responses, that is, transfer characteristics corresponding to audio effects given to audio signals of left and right ears for each predetermined rotational angle and to store a great amount of information on the transfer characteristics. The information is read from the storing means depending upon the change in direction of the head. The audio signal will be subjected to a necessary convolution-integration processing in real-time.
- The present invention was made under such circumstances.
- It is an object of the present invention to provide an audio signal reproducing apparatus having a simple structure using storing means having a low storing capacity which is capable of performing a binaural reproduction for providing a very natural localization of a sound image in which the positions of virtual sound sources are not changed by headphones even if a listener moves by reducing the amount of information on transfer characteristics from virtual sound sources necessary for binaural reproduction of audio signals with the headphones to both ears of the listener.
- An audio signal reproducing apparatus of the present invention comprises an audio signal reproducing apparatus, comprising:
means for storing transfer characteristics information representative of the transfer characteristics from virtual sound sources to both ears of a listener for each predetermined rotational angle corresponding to the movement of a head of the listener;
means for detecting the rotational angular position corresponding to the movement of the head of the listener;
interpolation operation means which reads from said storing means information on at least two transfer characteristics in the vicinity of the rotational angular position of the head represented by a detection output of said detecting means for interpolation-processing the read transfer characteristics information in the rotational angular position of the head represented by the detection output of said detecting means; and
audio signal processing means for processing left and right channel audio signals with the transfer characteristics information determined by said interpolation operation means, whereby the audio signals which have been processed by said audio signal processing means are reproduced as sounds by a headphone set. - The present invention will be further described hereinafter with reference to the following description of exemplary embodiments and the accompanying Figures, in which:-
- Fig. 1 is a block diagram schematically showing the structure of an audio signal reproducing apparatus described for reference purposes;
- Fig. 2 is a time chart schematically showing signals supplied to an operation unit of apparatus of Fig. 1;
- Fig. 3 is a schematic diagram illustrating the distance and the angle calculated by the operation unit of the apparatus of Fig. 1;
- Fig. 4 is a view for explaining the information on the transfer characteristics stored in a storing circuit of the operation unit in the apparatus of Fig. 1;
- Fig. 5 is a plan view showing the relative positional relation between virtual sound sources and a listener for explaining the operation of binaural reproducing performed by the apparatus of Fig. 1; and
- Fig. 6 is a block diagram schematically showing the structure of the audio signal reproducing apparatus of the present invention.
- An audio signal reproducing apparatus described for reference comprises a
headphone set 10 which is fitted over the head M of a listener P and a pair ofheadphones - Two
sliders 4L and r$ from which supportarms headphone set 10. A pair ofsignal detectors support arms signal detectors support arms sliders headphones - In the present apparatus the reference signal source 11 comprises an
ultrasonic signal source 12 and anultrasonic speaker 13 for generating an ultrasonic signal from theultrasonic signal source 12 as a reference signal. Each of the pair ofsignal detectors - An ultrasonic wave generated from the
ultrasonic speaker 13, that is, the position detection reference signal is a burst wave in which an ultrasonic wave having a given level is intermittently generated for a given period of time as shown at A in Fig. 2, or an ultrasonic wave, the phase of which may be detected like a so-called level modulated wave, the level of which changes in a given circle. - The pair of
signal detectors ultrasonic speaker 13 and generate respective detection signals shown at B and C in Fig. 2, each having a time lag depending upon the relative positional relation between the listener P and theultrasonic speaker 13. - Since the pair of
signal detectors support arm support arms support arms sliders headphone ultrasonic speaker 13, that is, the position detection reference signal stably and accurately without being located behind the head P of the listener P even if the listener P moves or rotates his head P. The pair of thesignal detectors sliders headphones signal detectors headphones - Each detection signal obtained by these
signal detectors operation unit 14. - The
operation unit 14 comprises first and secondedge detecting circuits signal detectors edge detecting circuit 17 to which an ultrasonic signal from theultrasonic signal sources 12, that is, the position detection reference signal is applied. - The first and second
edge detecting circuits signal detectors edge detecting circuits distance calculating circuit 18 and acircuit 19 for detecting the time difference between both ears. The thirdedge detecting circuit 17 detects the rise-up edge of the ultrasonic signal from theultrasonic signal source 12 and outputs a pulse signal corresponding to the rise-up edge as shown at F in Fig. 2. A pulse signal obtained by the thirdedge detection circuit 17 is supplied to thedistance calculating circuit 18. - The
distance calculating circuit 18 detects the time difference t₁ between pulse signals obtained by the third and firstedge detecting circuits edge detecting circuits ultrasonic speaker 13 and the center of the head M of the listener P represented as ℓ₀ in Fig. 3 based upon the time differences t₁, t₂ and the sound velocity V. - The sound velocity V may be preliminarily preset as a constant in the
distance calculating circuit 18 or alternatively may be changed with changes in atmospheric temperature, humidity and atmospheric pressure and the like. On calculating the distance ℓ, compensation may be conducted for the positional relation between thesignal detector - Signals representative of the distance ℓ₀, time differences t₁ and t₂ are fed to an
angle calculating circuit 20. - The
circuit 19 for detecting the time difference between both ears detects the time difference t₃ between the pulse signals generated by the first and secondedge detecting circuits angle calculating circuit 20. - The
angle calculating circuit 20 calculates an angle representative of the direction of the head M represented by an arrow ϑ₀ in Fig. 3 by using the time differences t₁, t₂, t₃, the distance ℓ₀, the sound velocity V and the radius r of the head M. The angle ϑ₀ can be determined, for example, by the equation 1 as follows:ultrasonic speaker 13 be the reference position of the virtual sound source. - Information on the rotation angle of the head of the listener obtained by the
angle calculating circuit 20 is provided to acontrol circuit 21. - In the audio signal reproducing apparatus of this embodiment, the
operation unit 14 includes astoring circuit 22 in which information on transfer characteristics from the virtual sound source to both ears of the listener in first quadrant of the rotational angular position of the head of the listener, for example, information on the transfer characteristics for each angle ϑ₁₁ to ϑ1n in the first quadrant. - Based upon the current angle position calculated by the
angle calculating circuit 20, thecontrol circuit 21 reads the information on the transfer characteristics corresponding to the current angles ϑ₁₁ to ϑ1n positions from thestoring circuit 22 if the current angle position is in the first quadrant in Fig. 4 and reads the transfer characteristics information in which the current angles ϑ₂₁ to ϑ2n corresponds to the angles ϑ₁₁ to ϑ1n in the first quadrant from thestoring circuit 22 if the current angle position is in the second quadrant in Fig. 4 and read the transfer characteristics information in which the current angles ϑ₃₁ to ϑ3n corresponds to the angles ϑ₁₁ to ϑ1n in the first quadrant from thestoring circuit 22 if the current angle position is in the third quadrant in Fig. 4 and read the transfer characteristics information in which the current angles ϑ₄₁ to ϑ4n correspond to the angles ϑ₁₁ to ϑ1n in the first quadrant from thestoring circuit 22 if the current angle position is in the fourth quadrant in Fig. 4 and supplies the read transfer characteristics information to an audiosignal processing circuit 23 together with a signal representative of the quadrant in which the current angular position is located. - Since the head of the listener is substantially spherical and rotary symmetric, the transfer characteristics from the virtual sound sources to both ears of the listener can be treated as symmetrical in each quadrant.
- Alternatively, in the
control circuit 21, two transfer characteristics in the vicinity of the rotational angular position of the head represented by the angular position information may be read form thestoring circuit 22 and the information on the transfer characteristics in the current head rotational angular position may be operated by, for example, linear interpolation processing, as described later with reference to Fig. 6. - Left and right channel audio signals SL and SR which are outputted from the
audio signal source 22 are supplied to the audiosignal processing circuit 23. - The
audio signal source 24 is an apparatus for outputting given left and right channel audio signals SL and SR, such as recording disc playback apparatus or radio communication receivers and the like. - The audio
signal processing circuit 23 performs a signal processing which provides the left and right channel audio signals SL and SR fed from theaudio signal source 24 with a given transfer characteristics form the virtual sound source to the both ears of the listener. The audiosignal processing circuit 23 comprises first tosixth switches signal processing units - The first to
sixth switches control circuit 21 representative of the quadrant to which the current angular position belongs. - The first and
second switches audio signal source 24 and supply the right channel audio signal SR to the first and secondsignal processing units 28a and 28b and supply the left channel audio signal SL to the third and fourthsignal processing units signal processing unit 28a and 28b and supply the right channel audio signal SR to the third and fourthsignal processing units - The third and
fourth switches signal processing circuit 23 and select as a right channel audio signal ER the output signal of thefirst adder 29R for adding the output signals of the first and thirdsignal processing unit 28a and 28c and select as a left channel audio signal EL the output signal of the second adder 29L for adding the output signals of the second and fourthsignal processing Units first adder 29L and select as a left channel audio signal EL the output signal of thesecond adder 29L when the current angular position is in the second or the fourth quadrant. - The third and fourth switches 26L and 26R perform switching of filters for the left and right channel audio signals EL and ER outputted from the audio
signal processing circuit 23 and output the left and right audio signals EL and ER unswitched when the current angular position is in the second or fourth quadrant and output the audio signals EL and ER from which high frequency components have been removed bylow pass filters - In each of
signal processing units control circuit 21. - In other words, the first signal processing unit 28a presets the impulse response {hRR(t, ϑ)} representative of transfer characteristics of the sound reproduced from the right channel audio signal SR to the right ear. The second
signal processing unit 28b presets the impulse response {hRL(t, ϑ)} representative of the transfer characteristics of the sound reproduced from the right channel audio signal SR to the left ear. The thirdsignal processing unit 28c presets the impulse response {hLR(t, ϑ)} representative of transfer characteristics of the sound reproduced form the left channel audio signal SL to the right ear. The fourthsignal processing unit 28d presents the impulse response {hLL(t, ϑ)} representative of the transfer characteristics of the sound reproduced from the left channel audio signal SL to the left ear. - When the current angular position of the head of the listener is in the first quadrant, the right channel audio signal SR is fed the first and second
signal processing units 28a and 28b. In the first signal processing unit 28a, the right channel audio signal SR is subjected to a signal processing of convolution-integration of the impulse response {hRR(t, ϑ)}. In the secondsignal processing unit 28b, the right channel audio signal SR is subjected to a signal processing of convolution-integration of the impulse response {hRL(t, ϑ)}. - The left channel audio signal SL is fed to the third and fourth
signal processing units signal processing unit 28c, the left channel audio signal SL is subjected to a signal processing of convolution-integration of the impulse response {hLR(t, ϑ)}. In the secondsignal processing unit 28d, the left channel audio signal SL is subjected to a signal processing of convolution-integration of the impulse response {hLL(t, ϑ)}. - The output signals from the first and third
signal processing units 28a and 28c are applied to theright channel adder 29R and are added with each other therein. The output signal of the right channel adder 28R is fed as the right channel studio signal ER via the right channel amplifier 31R to theright channel headphone 2R and reproduced as a sound. The output signals from the second and fourthsignal processing units left channel adder 29L and are added with each other therein. The output signal of the left channel adder 29 is fed as the left channel audio signal EL via the left channel amplifier 31L to theleft channel headphone 2L and reproduced as a sound. - When the current angular position of the head of the listener is in the second quadrant, the left and right channels of inputs and outputs are replaced with each other and a processing which is similar to that of the foregoing first quadrant is performed. Accordingly, a front localization sensation is provided. When the current angular position of the head of the listener is in the third and fourth quadrants a processing which is similar to those of the first and second quadrants is performed. Audio signals EL and ER from which high frequency components have been removed from the
low pass filters - In the audio signal reproducing apparatus described above information on the transfer characteristics in the rotational angular positions corresponding to the movement of the head of the listener calculated by the
angle calculating circuit 20 is formed based upon the information upon the transfer characteristics of the first quadrant stored in the storingcircuit 22. By performing a signal processing of the left and right channel audio signals SL and SR which responds to changes in transfer characteristics in association with the movement of the listener P and the rotation of the head M in real time in the audiosignal processing circuit 23 based upon the transfer characteristics data, good outside head localization sensation and front localization sensation are obtained in which the virtual sound sources are not moved as similarly to the case in which an audio signal is reproduced by a pair of speaker systems SL and SR which faces to the to the listener P and are remote therefrom and with each other as is shown in Figs. 5A, 5B and 5C in which relative positional relations between the virtual sound sources and the listener P are illustrated. - Fig. 5B shows that the listener P has approached to a pair of speaker systems SL and SR, that is, virtual sound sources from a position of Fig. 5A. Fig. 4C shows that the listener P rotates his head M towards the right speaker device SR. By performing a signal processing which can respond in real time to changes in transfer characteristics in association with the movement of the listener and the rotation of the head M as mentioned above, good head outside and front localization sensation in which no virtual sound source is moved can be obtained so that a binaural reproduction which can respond to any conditions of Figs. 5A, 5B and 5C can be performed.
- Since it suffices for the audio signal reproducing apparatus to store in storing means transfer characteristics information representative of the transfer characteristics from virtual sound sources to a listener of the first quadrant of the rotational angular position of the head of the listener, the amount of the information of the transfer characteristics to be stored in the storing means is small and the storing means having a low storing capacity can be used. The audio signal processing means forms the transfer characteristics information in the rotational angular position represented by a detection output from detecting means for detecting the rotational angular position depending upon the movement of the head of the listener in accordance with the transfer characteristics information of the first quadrant stored in the sorting means and processes the left and right channel audio signals for supplying the processed audio signals to the headphone set. Accordingly, a proper binaural reproduction can be performed for providing a very natural sound image localization sensation in which the positions of the virtual sound sources are not moved even if the listener moves.
- An embodiment of an audio signal reproducing apparatus of the present invention will now be described in detail with reference to the drawings.
- The audio signal reproducing apparatus of the present invention shown in Fig. 6 comprises a headphone set 40 which is fitted over the head M of a listener P and a pair of
headphones 42L and 42R are supported by ahead band 41 so that they are located in the vicinity of the left and right ears of the listener P, as is similar to the apparatus shown in Fig. 1. - Two
sliders arms signal detectors reference signal source 51 are provided at the tip ends of thesupport arms signal detectors support arms sliders head band 51 so that they are supported in positions remote from thehead band 51 and the pair ofheadphones 42L and 42R, that is the main body of the headphone set. - Also in this present embodiment, the
reference signal source 51 comprises anultrasonic signal source 52 and anultrasonic speaker 53 for generating an ultrasonic signal from theultrasonic signal source 52 as a reference signal. Each of the pair ofsignal detectors - An ultrasonic wave generated from the
ultrasonic speaker 53, that is, the position detection reference signal is a burst wave in which an ultrasonic wave having a given level is intermittently generated for a given period of time as is similar to the first embodiment, or an ultrasonic wave, the phase of which may be detected like a so-called level modulated wave, the level of which changes in a given circle. - The pair of
signal detectors ultrasonic speaker 53 and generate respective detection signals, each having a time lag depending upon the relative positional relation between the listener P and theultrasonic speaker 53. - Each detection signal obtained by these
signal detectors - The operation unit 54 comprises first and second
edge detecting circuit signal detectors edge detecting circuit 57 to which an ultrasonic signal from theultrasonic signal source 52, that is, the position detection reference signal is applied. - The first and second
edge detecting circuits signal detectors edge detecting circuits distance calculating circuit 58 and acircuit 59 for detecting the time difference between both ears. The thirdedge detecting circuit 57 detects the rise-up edge of the ultrasonic signal from theultrasonic signal source 52 and outputs a pulse signal corresponding to the rise-up edge. A pulse signal obtained by the thirdedge detection circuit 57 is supplied to thedistance calculating circuit 58. - The
distance calculating circuit 58 detects the time difference t₁ between pulse signals obtained by the third and firstedge detecting circuits edge detecting circuits ultrasonic speaker 53 and the center of the head M of the listener based upon the time differences t₁, t₂ and the sound velocity V. - Signals representative of the distance ℓ₀, time differences t₁ and t₂ are fed to an
angle calculating circuit 60. - The
circuit 59 for detecting the time difference between both ears detects the time difference t₃ between the pulse signals generated by the first and secondedge detecting circuits angle calculating circuit 60. - The
angle calculating circuit 60 calculates an angle ϑ₀ representative of the direction of the head M by using the time differences t₁, t₂, t₃, the distance ℓ₀, the sound velocity V and the radius r of the head M similarly to theangle calculating circuit 20 in the first embodiment. - Information on the rotation angular position head of the listener obtained by the
angle calculating circuit 60 is provided to an interpolation operation andprocessing circuit 61. - In the audio signal reproducing apparatus of the present embodiment, the operation unit 54 includes a storing
circuit 62 in which transfer characteristics information representative of the transfer characteristics from the virtual sound sources to both ears of the listener for each predetermined angle, which is larger than that of the angular positional information of the listener calculated by theangle calculating circuit 60. - The interpolation operation and
processing circuit 61 reads the information on two transfer characteristics in the vicinity of the rotational angular position of the head represented the current angular positional information calculated by theangle calculating circuit 60 and operates the transfer characteristics in the current rotational angular position of the head by, for example, a linear interpolation processing. - The interpolation operation and
processing circuit 61 may reads the information on more than two transfer characteristics in the vicinity of the current rotational angular position of the head represented by the angular positional information for performing secondary interpolation processing other than the linear interpolation processing. - The information on the transfer characteristics in the current rotational angular position obtained by the interpolation operation and
processing circuit 61 is supplied to an audiosignal processing circuit 63. - The audio
signal processing circuit 63 is also supplied with left and right channel audio signals SL and SR outputted from anaudio signal source 64. - The
audio signal source 64 is a device for outputting predetermined left and right channel audio signals SL and SR and may includes, for example, various recording disc playback devices, recording the playback device of wireless receivers and the like. - The audio
signal processing circuit 63 performs a signal processing which provides the left and right channel audio signals SL and SR fed from theaudio signal source 64 with a given transfer characteristics from the virtual sound source to the both ears of the listener. The audiosignal processing circuit 63 comprises first through fourthsignal processing units processing circuit 61. In each ofsignal processing units - In other words, the first
signal processing unit 65a presents the impulse response {hRR(t, ϑ)} representative of the transfer characteristics of the sound reproduced form the right channel audio signal SR to the right ear. The secondsignal processing unit 65b presets the impulse response {hRL(t, ϑ)} representative of the transfer characteristics of the sound reproduced from the right channel audio signal SR to the left ear. The thirdsignal processing unit 65c presets the impulse response {hLR(t, ϑ)} representative of the transfer characteristics of the sound reproduced from the left channel audio signal SL to the right ear. The fourthsignal processing unit 65d presets the impulse response {hLL(t, ϑ)} representative of the transfer characteristics of the sound reproduced from the left channel audio signal SL to the left ear. In the audiosignal processing circuit 63, the right channel audio signal SL is fed the first and secondsignal processing units 65a and 65n. In the firstsignal processing unit 65a, the right channel audio signal SL is subjected to a signal processing of convolution-integration of the impulse response {hRR(t, ϑ)}. In the secondsignal processing unit 65b, the right channel audio signal SR is subjected to a signal processing of convolution-integration of the impulse response {hRL(t, ϑ)}. - The left channel audio signal SL is fed to the third and fourth
signal processing units signal processing unit 65c, the left channel audio signal SL is subjected to a signal processing of convolution-integration of the impulse response {hLR(t, ϑ)}. In the secondsignal processing unit 65d, the left channel audio signal S is subjected to a signal processing of convolution-integration of the impulse response {hLL(t, ϑ)}. - The output signals from the first and third
signal processing units right channel adder 66R and are added with each other therein. The output signal of theright channel adder 66R is fed as the right channel audio signal ER via the right channel amplifier 68R to theright channel headphone 4R of theheadphones 40 and reproduced as a sound. The output signals from the second and fourth signal processing units 64b and 64a are applied to theleft channel adder 66L and are added with each other therein. The output signal of theright channel adder 66L is fed as the left channel audio signal ER via the left channel amplifier 68L to the left channel headphone 42L of the headphone set 40 and reproduced as a sound. - In the thus formed audio signal reproducing apparatus information on two transfer characteristics in the vicinity of the rotational angular position represented by the current angular positional information is read from the storing
circuit 62 based upon the current angular positional information calculated by theangle calculating circuit 60. The transfer characteristics information in the current rotational angular position are operated by a linear interpolation processing in theinterpolation operation circuit 61. By performing a signal processing which responds to changes in transfer characteristics in association with the movement of the listener and the rotation of the head M in real time in the audiosignal processing circuit 63 based upon the transfer characteristics data, good outside head localization sensation and front localization sensation are obtained in which the virtual sound sources are not moved as similarly to the case in which an audio signal is reproduced by a pair of speaker systems which faces to the listener and are remote therefrom and with each other. - As mentioned above, in the audio signal reproducing apparatus of the present invention, information on at least two transfer characteristics in the vicinity of the rotational angular position of the head represented by the detection output from detecting means for detecting the rotational angular position of the head of the listener at a solution higher than that of the transfer characteristics information stored in the storing means is read from the storing means. The transfer characteristics information in the rotational angular position of the head represented by the detection output are interpolation-operated by interpolation operation means. Accordingly, the amount of the information on the transfer characteristics stored in the storing means can be reduced. The audio signal processing means processes the left and right channel audio signals based upon the transfer characteristics information determined by the interpolation operation means. The processed audio signals are supplied to the headphones, resulting in that a proper binaural reproduction can be achieved for providing very natural sound image localization sensation in which the positions of the virtual sound sources do not move even if a listener moves.
Claims (5)
- An audio signal reproducing apparatus, comprising:
means (62) for storing transfer characteristics information representative of the transfer characteristics from virtual sound sources to both ears of a listener for each predetermined rotational angle corresponding to the movement of a head of the listener;
means for detecting (45L, R, 51, 55-59) the rotational angular position corresponding to the movement of the head of the listener;
interpolation operation means (61) which reads from said storing means information on at least two transfer characteristics in the vicinity of the rotational angular position of the head represented by a detection output of said detecting means for interpolation-processing the read transfer characteristics information in the rotational angular position of the head represented by the detection output of said detecting means; and
audio signal processing means (63) for processing left and right channel audio signals with the transfer characteristics information determined by said interpolation operation means, whereby the audio signals which have been processed by said audio signal processing means are reproduced as sounds by a headphone set (40). - An apparatus according to claim 1, in which said detecting means includes:
a pair of signal detecting elements (45L, R) for detecting a reference signal transmitted from a reference signal source (53);
means (78) for calculating the distance between said reference signal source and the head of the listener from the phase difference between the detection output signals from said pair of the signal detecting elements and said reference signal; and
means (59) for detecting the time difference between the detection output signals from said pair of signal detecting elements, whereby the rotational angular position of the head of the listener is calculated by using information on the distance obtained from said distance calculating means and on the time difference obtained from said time difference detecting means. - An apparatus according to claim 1 or 2, in which said audio signal processing means includes:
a first signal processor (65a) for applying to the right channel input audio signal (SR) a convolution-integration of the impulse response corresponding to transfer characteristics of a right channel reproduced audio signal of an input audio signal to the right ear;
a second signal processor (65b) for applying to the right channel input audio signal (SR) a convolution-integration of the impulse response corresponding to the transfer characteristics of the right channel reproduced audio signal to the left ear;
a third signal processor (65c) for applying to the left channel input audio signal (SL) a convolution-integration of the impulse response corresponding to the transfer characteristics of the left channel reproduced audio signal of the input audio signal to the right ear;
a fourth signal processor (65d) for applying to the left channel input audio signal (SL) a convolution-integration of the impulse response corresponding to the transfer characteristics of the left channel reproduced audio signal to the left ear;
a first means for adding (66R) the output of said first signal processing unit with the output of the third signal processing unit;
a second means for adding (66L) the output of said second signal processing unit with the output of the fourth signal processing unit, whereby the outputs (ER, EL) of the first and second adding means are supplied to the right and left channel headphones of said headphone set, respectively. - An apparatus according to claim 1, 2 or 3 in which said interpolation operation means (61) reads from said storing means (62) the information on two transfer characteristics in the vicinity of the rotational angular position of the head represented by the detection output from said detecting means for linear interpolation operating the information on the transfer characteristics in the rotational angular position of the head represented by the detection output from said detecting means.
- An apparatus according to claim 1, 2 and 3, in which said interpolation operation means reads from said storing means the information on more than two transfer characteristics in the vicinity of the rotational angular position of the head represented by the detection output from said detecting means for secondary interpolation operating the information on the transfer characteristics in the rotational angular position of the head represented by the detection output from said detecting means.
Applications Claiming Priority (7)
Application Number | Priority Date | Filing Date | Title |
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JP852090 | 1990-01-19 | ||
JP8514/90 | 1990-01-19 | ||
JP2008520A JP2893780B2 (en) | 1990-01-19 | 1990-01-19 | Sound signal reproduction device |
JP2008514A JP2751512B2 (en) | 1990-01-19 | 1990-01-19 | Sound signal reproduction device |
JP851490 | 1990-01-19 | ||
JP8520/90 | 1990-01-19 | ||
EP91902738A EP0464217B1 (en) | 1990-01-19 | 1991-01-18 | Apparatus for reproducing acoustic signals |
Related Parent Applications (2)
Application Number | Title | Priority Date | Filing Date |
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EP91902738.3 Division | 1991-01-18 | ||
EP91902738A Division EP0464217B1 (en) | 1990-01-19 | 1991-01-18 | Apparatus for reproducing acoustic signals |
Publications (3)
Publication Number | Publication Date |
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EP0664660A2 true EP0664660A2 (en) | 1995-07-26 |
EP0664660A3 EP0664660A3 (en) | 1995-08-09 |
EP0664660B1 EP0664660B1 (en) | 2000-09-27 |
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Application Number | Title | Priority Date | Filing Date |
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EP95104929A Expired - Lifetime EP0664660B1 (en) | 1990-01-19 | 1991-01-18 | Audio signal reproducing apparatus |
EP91902738A Expired - Lifetime EP0464217B1 (en) | 1990-01-19 | 1991-01-18 | Apparatus for reproducing acoustic signals |
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Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP91902738A Expired - Lifetime EP0464217B1 (en) | 1990-01-19 | 1991-01-18 | Apparatus for reproducing acoustic signals |
Country Status (5)
Country | Link |
---|---|
EP (2) | EP0664660B1 (en) |
KR (1) | KR920702175A (en) |
CA (1) | CA2048686C (en) |
DE (2) | DE69120150T2 (en) |
WO (1) | WO1991011080A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0762803A2 (en) * | 1995-08-31 | 1997-03-12 | Sony Corporation | Headphone device |
FR2744871A1 (en) * | 1996-02-13 | 1997-08-14 | Sextant Avionique | SOUND SPATIALIZATION SYSTEM, AND PERSONALIZATION METHOD FOR IMPLEMENTING SAME |
EP2005793A2 (en) * | 2006-04-04 | 2008-12-24 | Aalborg Universitet | Binaural technology method with position tracking |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0795698A (en) * | 1993-09-21 | 1995-04-07 | Sony Corp | Audio reproducing device |
DE69632889T2 (en) * | 1995-05-22 | 2005-07-21 | Victor Company of Japan, Ltd., Yokohama | Player with headphones |
EP2288178B1 (en) | 2009-08-17 | 2012-06-06 | Nxp B.V. | A device for and a method of processing audio data |
US9706304B1 (en) * | 2016-03-29 | 2017-07-11 | Lenovo (Singapore) Pte. Ltd. | Systems and methods to control audio output for a particular ear of a user |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS58116900A (en) * | 1982-11-15 | 1983-07-12 | Sony Corp | Stereophonic reproducing device |
WO1989003632A1 (en) * | 1987-10-15 | 1989-04-20 | Cooper Duane H | Head diffraction compensated stereo system |
JPH01121000A (en) * | 1987-11-05 | 1989-05-12 | Sony Corp | Audio reproducing device |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5419242B2 (en) | 1973-06-22 | 1979-07-13 | ||
JPS5165901A (en) * | 1974-12-05 | 1976-06-08 | Sony Corp | |
US4076677A (en) | 1976-06-23 | 1978-02-28 | Desoto, Inc. | Aqueous copolymer dispersions and method of producing the same |
JPS54109401A (en) * | 1978-02-16 | 1979-08-28 | Victor Co Of Japan Ltd | Signal converter |
JP3155592B2 (en) * | 1991-12-11 | 2001-04-09 | 武藤工業株式会社 | Method and apparatus for correcting progressive dimensions |
-
1991
- 1991-01-18 DE DE69120150T patent/DE69120150T2/en not_active Expired - Lifetime
- 1991-01-18 WO PCT/JP1991/000057 patent/WO1991011080A1/en active IP Right Grant
- 1991-01-18 EP EP95104929A patent/EP0664660B1/en not_active Expired - Lifetime
- 1991-01-18 DE DE69132430T patent/DE69132430T2/en not_active Expired - Lifetime
- 1991-01-18 KR KR1019910701121A patent/KR920702175A/en not_active Application Discontinuation
- 1991-01-18 EP EP91902738A patent/EP0464217B1/en not_active Expired - Lifetime
- 1991-01-18 CA CA002048686A patent/CA2048686C/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS58116900A (en) * | 1982-11-15 | 1983-07-12 | Sony Corp | Stereophonic reproducing device |
WO1989003632A1 (en) * | 1987-10-15 | 1989-04-20 | Cooper Duane H | Head diffraction compensated stereo system |
JPH01121000A (en) * | 1987-11-05 | 1989-05-12 | Sony Corp | Audio reproducing device |
Non-Patent Citations (2)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 13 no. 364 (E-805) ,14 August 1989 & JP-A-01 121000 (SONY CORP) 12 May 1989, * |
PATENT ABSTRACTS OF JAPAN vol. 7 no. 226 (E-202) ,7 October 1983 & JP-A-58 116900 (SONY KK) 12 July 1983, * |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0762803A2 (en) * | 1995-08-31 | 1997-03-12 | Sony Corporation | Headphone device |
EP0762803A3 (en) * | 1995-08-31 | 2006-07-26 | Sony Corporation | Headphone device |
FR2744871A1 (en) * | 1996-02-13 | 1997-08-14 | Sextant Avionique | SOUND SPATIALIZATION SYSTEM, AND PERSONALIZATION METHOD FOR IMPLEMENTING SAME |
EP0790753A1 (en) * | 1996-02-13 | 1997-08-20 | Sextant Avionique | System for sound spatial effect and method therefor |
US5987142A (en) * | 1996-02-13 | 1999-11-16 | Sextant Avionique | System of sound spatialization and method personalization for the implementation thereof |
EP2005793A2 (en) * | 2006-04-04 | 2008-12-24 | Aalborg Universitet | Binaural technology method with position tracking |
Also Published As
Publication number | Publication date |
---|---|
DE69132430D1 (en) | 2000-11-02 |
DE69132430T2 (en) | 2001-04-05 |
EP0464217A4 (en) | 1992-06-24 |
DE69120150T2 (en) | 1996-12-12 |
CA2048686C (en) | 2001-01-02 |
EP0464217B1 (en) | 1996-06-12 |
EP0464217A1 (en) | 1992-01-08 |
KR920702175A (en) | 1992-08-12 |
EP0664660B1 (en) | 2000-09-27 |
EP0664660A3 (en) | 1995-08-09 |
CA2048686A1 (en) | 1991-07-20 |
WO1991011080A1 (en) | 1991-07-25 |
DE69120150D1 (en) | 1996-07-18 |
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