JP2007143008A - Sound pickup switching apparatus and sound pickup switching method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a binaural sound listening apparatus for reproducing a reproduction sound of an audio apparatus and an environmental sound at the outside of a mobile body listenable to be in a way of not susceptible to the effect of differences from listening characteristics of each listener by using a speaker inside the mobile body. <P>SOLUTION: A first cylindrical structure 1 mounted with microphones 12a, 12b is arranged to the outside of the mobile body 100, and a crosstalk canceller 2 for allowing speakers 5a, 5b to sound binaural signals after canceling crosstalk signals is provided to the inside of the mobile body. The crosstalk canceller 2 includes filters 21a, 21b, 21c, 21d, 23a, 23b for storing a head transfer function in advance, and the head transfer function is configured to be a function obtained on the basis of the crosstalk cancel signals with respect to external sounds picked up by a pair of microphones 74a, 74b mounted to a second cylindrical structure 74 prepared in advance so as to realize the binaural sound listening apparatus. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a stereo sound reproducing device and an on-vehicle acoustic device provided with a microphone outside the vehicle, and in particular, outdoor environmental sound subjected to crosstalk cancellation processing with a window closed, and reproduced sound of a stereo audio device. The present invention relates to a sound collection switching device and a sound collection switching method that allow a driver to listen to the sound.

  2. Description of the Related Art Conventionally, there has been an in-vehicle acoustic device that drives a speaker disposed in a vehicle interior by a signal from a microphone disposed outside the vehicle in order to recognize an emergency vehicle or the like. It is preferable to allow the driver to listen to the surrounding sound of the vehicle in the sound-insulated vehicle and to drive the vehicle appropriately while avoiding danger.

In Patent Document 1, a plurality of microphones are arranged at the four corners outside the vehicle, a plurality of speakers are arranged at the four corners of the vehicle interior, and each microphone is associated with each speaker so that sounds outside the vehicle have a sense of direction. The vehicle-mounted acoustic device is disclosed in which the position of the emergency vehicle or the like is recognized in the closed vehicle by reproducing the sound.
JP-A-8-33085

  However, in the in-vehicle acoustic device disclosed in Patent Document 1, it is necessary to install a plurality of microphones and corresponding speakers. Therefore, in order to generate a three-dimensional sound field, the microphones are at least in four directions outside the vehicle. In addition, it is necessary to install speakers in four directions in the car corresponding to these microphones. Although it is possible for the experimental vehicle to arrange microphones in four directions outside the vehicle, it is not preferable in terms of safe driving to arrange microphones having protrusions at the four corners of the vehicle. In addition, it is not preferable to arrange speakers in four directions in a limited vehicle in terms of effective use of the vehicle interior space.

  Therefore, the present invention has been made to solve the above-described problems, and environmental sounds outside the moving body collected by using one binaural microphone arranged outside the moving body are insulated. Stereo sound that is reproduced using two speakers in the moving body, and that makes it difficult for listeners with different listening characteristics to be affected by the difference in listening characteristics and properly recognize the situation outside the moving body. A sound collection switching device and a sound collection switching method for reproducing and reproducing the sound of a stereo audio device and enabling environmentally sound outside the vehicle to be played safely while being switched with the reproduction sound of the audio device. The purpose is to provide.

  According to a first aspect of the present invention, a binaural sound generated by converting an external sound picked up by a pair of microphones attached to the outside of a sealed space by a head transfer function of a listener and the sealed sound In a sound collection switching device for switching and outputting stereo sound emitted from a sound source mounted in a space, a first cylinder having a diameter substantially the same as a listener's head shape and fitted with the pair of microphones A cross-talk canceller that cancels a crosstalk signal generated when the binaural sound is output, and the crosstalk canceller includes a filter that stores a head-related transfer function obtained in advance, The head-related transfer function is a crosstalk for the external sound picked up by a pair of microphones mounted on a second cylindrical structure prepared in advance. Providing sound pickup switching apparatus which is a function obtained based on Yanseru signal.

  According to a second aspect of the present invention, a binaural sound generated by converting an external sound picked up by a pair of microphones attached to the outside of a sealed space by a head transfer function of a listener and the inside of the sealed space In the sound collecting switching method for switching and outputting stereo sound emitted from a sound source attached to the sound source, the first cylindrical structure is provided in the sealed space and has a diameter substantially the same as the head shape of the listener. A crosstalk signal generated when the pair of microphones is attached to the body and the binaural sound is output by a crosstalk canceller is cancelled, and a processing of a crosstalk signal generated when the binaural signal is output is prepared in advance. Using the head-related transfer function obtained by using a two-cylindrical structure, the chrominance for the external sound collected by a pair of microphones is used. It provides a sound pickup switching method and performing seeking talk cancellation signal.

  According to the present invention, the first cylindrical structure having a diameter substantially the same as the listener's head shape and fitted with a pair of microphones, and the crosstalk signal generated when binaural sound is output are canceled out. A crosstalk canceller, the crosstalk canceller has a filter storing a head-related transfer function obtained in advance, and the head-related transfer function is attached to a second cylindrical structure prepared in advance. Since there is a special configuration that is a function obtained based on a crosstalk cancellation signal with respect to external sound collected by a microphone, the external sound of the mobile object that is collected using one binaural microphone arranged outside the mobile object Environmental sound is reproduced using two speakers in a sound-isolated moving body, and even listeners with different listening characteristics are affected by the difference in listening characteristics. It is difficult to reproduce environmental sounds that properly recognize the situation outside the moving body and drive the moving body safely. It is possible to switch between listening to the reproduction sound of the stereo audio device and the environmental sound outside the vehicle. A sound collection switching device and a sound collection switching method can be realized.

A sound collection switching device according to an embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is a perspective view of a vehicle equipped with a sound collection switching device according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration example of the sound collection switching device according to the embodiment of the present invention.
FIG. 3 is a diagram showing a cylindrical structure to which a pair of microphones of the sound collection switching device main part according to the embodiment of the present invention is attached.

FIG. 4 is a block diagram showing a configuration example of a crosstalk canceller of the main part of the sound collection switching device according to the embodiment of the present invention.
FIG. 5 is a diagram showing a configuration of a filter characteristic measuring apparatus mounted on the crosstalk canceller according to the embodiment of the present invention.

FIG. 6 is a diagram showing a cylindrical structure to which a pair of microphones used in the characteristic measuring apparatus according to the embodiment of the present invention is attached.
FIG. 7 is a diagram showing an impulse response characteristic measured by the characteristic measuring apparatus according to the embodiment of the present invention.

FIG. 8 is a diagram of the frequency characteristics of the impulse response measured by the characteristic measuring apparatus according to the embodiment of the present invention.
FIG. 9 is a diagram showing the structure of a binaural microphone.

FIG. 10 is a diagram showing an impulse response characteristic measured using a binaural microphone.
FIG. 11 is a diagram of frequency characteristics of an impulse response measured using a binaural microphone.

FIG. 12 is a diagram showing an application example of a vehicle equipped with a sound collection switching device according to an embodiment of the present invention.
The sound collection switching device generates environmental sounds outside the moving body using one binaural microphone arranged outside the moving body, using two speakers in the sound-isolated moving body, and receives the listening characteristics. Receiving environmental sounds that are not easily affected by differences in listening characteristics and properly recognizing the situation outside the mobile body, while switching to the playback sound of the stereo audio device, A first cylindrical structure that is provided outside the mobile body, has a diameter substantially the same as the listener's head shape, and is equipped with a pair of microphones. A crosstalk canceller for processing the binaural signal so as to cancel a crosstalk signal generated when the binaural signal is produced by a speaker. The talk canceller has a filter storing a head-related transfer function obtained in advance, and the head-related transfer function corresponds to the external sound picked up by a pair of microphones mounted on a second cylindrical structure prepared in advance. The function was obtained as a crosstalk cancellation signal.

The configuration of the sound collection switching device will be described.
A car 100 equipped with the sound collection switching device shown in FIG. 1 has a cylindrical structure 1 installed on the roof of the car, and speakers 5a and 5b arranged in the car.

  A sound collection switching device 10 shown in FIG. 2 includes a cylindrical structure 1, a pair of microphones 12a and 12b, a crosstalk canceller 2, a car audio 3, a changeover switch SW1, an amplifier 4, and speakers 5a and 5b. The sound generated from the speakers 5 a and 5 b is received by the listener 6.

  The cylindrical structure 1 which is a main part of the sound collection switching device 10 shown in FIG. 3B is provided with ear canals 13a and 13b, and microphones 12a and 12b are arranged at the entrance portions of the ear canals. The microphones 12a and 12b are covered with windshields 11a and 11b.

  The crosstalk canceller 2 shown in FIG. 4 includes filters 21a, 21b, 21c, and 21d, adders 22a and 22b, and filters 23a and 23b. The amplifier 4 includes a left amplifier 41a and a right amplifier 41b.

The operation of the sound collection switching device will be described with reference to FIGS.
First, the microphones 12a and 12b attached to the cylindrical structure 1 arranged on the roof of the car collect binaural sound and obtain a binaural sound signal. The crosstalk canceller 2 generates a binaural reproduction signal to which a signal for canceling the crosstalk component generated in the listening space is added when the binaural audio signal is generated from the speakers 5a and 5b. The changeover switch SW1 is turned on to the a side, and a binaural reproduction signal is input to the amplifier 4. The binaural reproduction signal amplified by the amplifier 4 is produced from the speakers 5a and 5b. A signal collected by the microphone 12a is received by the left ear of the listener 6 and a signal collected by the microphone 12b is received by the right ear of the listener 6, so that the listener blocks the environmental sound outside the vehicle. Can be heard in the car.

  Here, when the signals collected by the microphones 12a and 12b are produced from the speakers 5a and 5b without performing the crosstalk component cancellation processing, the signal produced from the left speaker 5a is the left side of the listener 6. And the crosstalk sound is heard with the right ear. The crosstalk sound of the signal generated from the right speaker 5 b is heard by the left ear of the listener 6. The listener 6 cannot listen to the environmental sound having a predetermined localization due to the crosstalk sound. Since the binaural signal picked up by the microphones 12a and 12b is used to cancel the crosstalk component generated between the speakers 5a and 5b and the ears 6 of the listener 6 in advance by using the crosstalk canceller 2, the listener 6 Listen to environmental sounds outside the car.

The windshields 11a and 11b attached to the microphones 12a and 12b are windshields for attenuating wind noise generated during traveling.
The car audio 3 is a normally used car audio device. The changeover switch SW1 is operated by the listener to switch between car audio and environmental sound outside the vehicle. Further, as an application example, a siren sound detection device (not shown) is built in the sound collection switching device 10 and when a siren sound is detected in binaural sound received by the microphones 12a and 12b, the switch SW1 is set by a control unit (not shown). You may provide the function thrown into a side. The siren sound is an acoustic signal containing a lot of sine wave components and can be easily detected by frequency analysis of binaural sound.

The crosstalk canceller 2 will be described with reference to FIG.
First, the binaural signals binaural signals P _L (t) and P _R (t) of the left and right channels are input to the input terminals. The left channel binaural signal is input to the filters 21a and 21b. The filter 21a convolves the head-related transfer function h _RS (t) with the input signal, and the filter 21b convolves the head-related transfer function h _LO (t) to generate a signal having a characteristic with the polarity reversed. The input signal of the right channel convolves the head-related transfer function h _RO (t) with the filter 21c, and then generates a signal having a characteristic with the polarity reversed. The filter 21d convolves the head-related transfer function h _LS (t). Generate a signal with a characteristic.

  The signals generated by the filters 21a and 21c are added by the adder 22a, and then the characteristic of d (t) is given by the filter 23a to generate the left channel binaural reproduction signal. The signals generated by the filters 21b and 21d are added by the adder 22b, and then the characteristic of d (t) is given by the filter 23b to generate a right channel binaural reproduction signal. The binaural reproduction signals of the left and right channels are amplified by the left amplifier 41a and the right amplifier 41b of the amplifier 4, and are generated by the left and right speakers 5a and 5b.

  By using the crosstalk canceller 2, the binaural signal collected by the microphones 12a and 12b is generated as a binaural reproduction signal that cancels out the crosstalk component generated between the speakers 5a and 5b and the ears 6 of the listener 6 in advance. The binaural reproduction signal is generated from the speakers 5a and 5b, and the listener 6 can listen to environmental sounds outside the vehicle with a sense of reality.

  Here, the characteristics of the crosstalk signal generated between both ears of the speakers 5a and 5b and the listener 6 are different for each listener. In many cases, the canceling characteristic of the crosstalk component suitable for a certain listener does not effectively act on other listeners. When the crosstalk cancellation signal generated by the crosstalk canceller 2 does not cancel the listener's crosstalk, the crosstalk cancellation signal included in the binaural reproduction signal is received as a signal having a reverse phase component that does not exist in nature. The characteristics of the filters 21a, 21b, 21c, and 21d must be characteristics that make up a binaural reproduction signal that has a low sense of reverse phase for listeners with different listening characteristics.

  With reference to FIG. 5, the configuration and operation of the acoustic signal transfer characteristic measuring device 7 for obtaining the head-related transfer functions stored in the filters 21a, 21b, 21c, and 21d will be described. The acoustic signal transfer characteristic measuring device 7 is a device for obtaining characteristics for generating a crosstalk cancellation signal in which the signal component for canceling the crosstalk is not easily heard by the listener 6 as a reverse phase signal.

  The acoustic signal transfer characteristic measuring device 7 includes a personal computer 71, an amplifier 72, a speaker 73, a cylindrical structure 74 to which left and right microphones 74a and 74b are attached, and amplifiers 75a and 75b.

First, a measurement signal such as an impulse sound or white noise is generated by the personal computer 71. The measurement signal is amplified by the amplifier 72 and applied to the speaker 73. The measurement signal generated from the speaker 73 is received by the left and right microphones 74 a and 74 b attached to the cylindrical structure 74. The received signal is amplified by the amplifiers 75a and 75b, and the signal obtained by the amplification is input to the personal computer 71. The personal computer 71 compares the generated measurement signal with the input signal to obtain head-related transfer functions h _ls (t) and h _lo (t) from the speaker 73 to the left and right microphones 74a and 74b. Similarly, the speaker 73 is placed on the right side opposite to the cylindrical structure 74 and measured, and the head-related transfer functions h _ro (t) and h _rs (t) are obtained.

  FIG. 6A is a top view of a cylindrical structure 74 to which left and right microphones 74a and 74b are attached, and FIG. 6B is a perspective view. Compared to the dummy head type microphone, it has no pinna or ear canal. The position where the diaphragm (not shown) built in the microphones 74a and 74b is arranged is not the position of the eardrum in the so-called dummy head type microphone, but the position of the surface of the cylindrical structure 74. Due to their characteristic shape and arrangement, when the acoustic signal transfer characteristic measuring device 7 obtains the crosstalk canceling characteristics, the filters 21a, 21b for generating a crosstalk canceling signal that is difficult to be heard as a reverse phase signal, The characteristics of 21c and 21d are obtained.

With reference to FIG. 7, the signal waveform obtained by measuring with the acoustic signal transfer characteristic measuring apparatus 7 will be described. The measurement signal is a waveform related to the head-related transfer function obtained using the raised cosine impulse signal. The horizontal axis is time, and the vertical axis is a voltage value normalized between the respective waveforms. (A) to (D) are waveforms corresponding to the head-related transfer functions h _1S (t), h _lo (t), h _rS (t), and h _ro (t) in this order. A waveform relating to the characteristic of d (t) shown in (E) is given by the following equation.

d (t) = {h _lS (t) * h _rS (t) −h _lO (t) * h _rO (t)} ⁻¹
Note that * is a symbol indicating multiplication.
The frequency characteristics of these characteristics will be described with reference to FIG.

This figure shows the characteristics obtained by Fourier expansion of the impulse response waveform shown in FIG. The horizontal axis is frequency, and the vertical axis is response signal level. The frequency positions of 100 Hz, 1 kHz, and 10 kHz are indicated by broken lines. The gain difference between the broken line and the broken line in the response characteristic is 10 dB. (A) to (E) are frequency characteristics related to the head-related transfer functions h _1S (t), h _lo (t), h _rS (t), h _ro (t), and d (t) in this order.

Similar characteristics obtained when using a dummy head microphone are shown for comparison.
FIG. 9 shows the structure of a dummy head microphone 80 used for characteristic comparison. The dummy head microphone 80 is provided with pinna 84a and 84b and ear canals 83a and 83b on an artificial head 81, and the microphones 82a and 82b are arranged at the position of the eardrum in the back of the ear canals 83a and 83b. The dummy head microphone 80 having the same shape as that of the listener is supposed to obtain a listening signal having a characteristic close to the sound heard by the listener.

  FIG. 10 shows a waveform of an impulse response measured using a dummy head microphone 80 instead of using the microphones 74 a and 74 b attached to the cylindrical structure 74. Other measurement conditions are the same as those shown in FIG.

  FIG. 11 shows frequency characteristics obtained by Fourier expansion of the characteristics obtained in FIG. The conditions other than using the dummy head microphone 80 are the same as the characteristics obtained in FIG.

  The characteristic shown in the figure is that the negative crest value is smaller than the characteristic crest value shown in FIG. 7 obtained by using the microphones 74 a and 74 b attached to the cylindrical structure 74, and the dummy head microphone 80. In the characteristic of FIG. 10 obtained by using, a signal having a negative peak value (absolute value) similar to the positive peak value is obtained. The characteristic shown in FIG. 7 is closer to the raised cosine waveform than the characteristic shown in FIG. Further, in the vibration attenuation waveform, a signal having a high peak value is generated a plurality of times in the characteristic shown in FIG. FIG. 7 is closer to the input signal (raised cosine) at the time of measurement.

  The frequency characteristics shown in FIG. 8 are less disturbed in frequency characteristics (unevenness in response characteristics) than those shown in FIG. The characteristics obtained with the microphones 74 a and 74 b attached to the cylindrical structure 74 are flatter than the characteristics obtained with the dummy head microphone 80. When the crosstalk is canceled using the dummy head microphone 80, the crosstalk cancellation signal may be larger than the crosstalk component to be canceled. The signal component is heard as a reverse phase signal. The crosstalk canceller 2 that uses the characteristics of the head-related transfer functions shown in FIGS. 7 and 8 for the filters 21a, 21b, 21c, 21d, 23a, and 23b is generated between the speakers 5a and 5b and the ears of the listener 6. Since a crosstalk cancellation signal having a level larger than that of the crosstalk component is not generated, the degree to which the listener hears the crosstalk cancellation signal as a signal having a reverse phase feeling is small.

  The characteristics necessary for the filters 21a, 21b, 21c, and 21d used to reproduce the binaurally recorded sound signal are as follows. Sound waves generated from the speakers 5a and 5b are shielded by the head of the listener 6, and This is a characteristic for canceling the crosstalk sound that diffracts and arrives at the ear on the opposite side. A characteristic that a part of the sound wave generated from the speakers 5a and 5b is reflected by the auricle, and the reflected sound wave and the directly arriving sound wave are synthesized in the same phase and enhanced, or synthesized in the opposite phase and attenuated. In addition, it is not necessary to correct a characteristic generated by being enhanced or attenuated at a specific frequency caused by resonance or anti-resonance of the ear canal. The characteristics measured using the microphones 74a and 74b attached to the cylindrical structure 74 shown in FIG. 6 are the filters 21a, 21b, 21c, 21d, 23a, and 23b of the crosstalk canceller 2 shown in FIG. As a result, it is possible to perform suitable crosstalk cancellation for a plurality of listeners whose listening characteristics are different from each other.

An application example of the sound collection switching device will be described with reference to FIG.
The vehicle 100a equipped with the sound collection switching device 10 shown in FIG. 1 is installed in the trunk in comparison with the car 100 equipped with the sound collection switching device 10 shown in FIG. Is different in that. The single cylindrical structure 1 to which the microphones 12a and 12b are attached can collect ambient environmental sounds, so it can be installed in any place that does not block the driver's field of view, and collects ambient sounds similar to those described above. be able to. In FIG. 1, the speakers 5a and 5b are arranged at the upper part of the driver's seat, but in FIG. 12, the speakers 5a and 5b are arranged at the front of the driver's seat. The speakers 5a and 5b can be arranged at arbitrary positions within a range in which the crosstalk component generated in the listening space is canceled.

  As described above, according to the sound collection switching device 10 shown in the present embodiment, the pair of microphones 12a is provided outside the moving body 100, has the same diameter as the head shape of the listener 6, and has a pair of microphones 12a. , 12b and a crosstalk canceller 2 for canceling a crosstalk signal generated when a binaural sound is produced by the speakers 5a, 5b. A pair of microphones having filters 21a, 21b, 21c, 21d, 23a, and 23b that store the obtained head-related transfer functions, the head-related transfer functions being mounted on a second cylindrical structure 74 prepared in advance. Since there is a special configuration which is a function obtained based on the crosstalk cancellation signal for the external sound collected by 74a and 74b, it is arranged outside the mobile body. The environmental sound outside the moving body picked up by using one binaural microphone is reproduced using the two speakers 5a and 5b in the sound-blocking moving body, and for listeners with different listening characteristics, Stereo audio device playback sound and environmental sound outside the vehicle that can be safely operated by playing environmental sounds that make it difficult to be affected by differences in listening characteristics and properly recognize the situation outside the mobile body Sound collection switching device and sound collection switching method can be realized.

  The present invention can be applied to a sound collection switching device for listening to an outdoor environmental sound while the window is closed while switching between an environmental sound to be heard by the driver by performing a crosstalk cancellation process and a reproduction sound of the stereo audio device.

1 is a perspective view of a vehicle equipped with a sound collection switching device according to an embodiment of the present invention. It is a block diagram which shows the structural example of the sound collection switching apparatus which concerns on implementation of this invention. It is a figure which shows the cylindrical structure to which a pair of microphone of the sound collection switching apparatus principal part which concerns on implementation of this invention is attached | subjected. It is a block diagram which shows the structural example of the crosstalk canceller of the sound collection switching apparatus principal part which concerns on implementation of this invention. It is a figure which shows the structure of the characteristic measurement apparatus of the filter mounted in the crosstalk canceller which concerns on implementation of this invention. It is a figure which shows the cylindrical structure to which a pair of microphone used with the characteristic measuring apparatus which concerns on implementation of this invention is attached | subjected. It is a figure which shows the impulse response characteristic measured with the characteristic measuring apparatus based on implementation of this invention. It is a figure of the frequency characteristic of the impulse response measured with the characteristic measuring apparatus based on implementation of this invention. It is a figure which shows the structure of a binaural microphone. It is a figure which shows the impulse response characteristic measured using the binaural microphone. It is a figure of the frequency characteristic of the impulse response measured using the binaural microphone. It is the figure which showed the application example of the vehicle carrying the sound collection switching apparatus which concerns on implementation of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylindrical structure 2 Crosstalk canceller 3 Car audio 4 Amplifier 5a, 5b Speaker 6 Listener 7 Acoustic signal transfer characteristic measuring device 10 Sound collection switching device 11a, 11b Windshield 12a, 12b Microphones 13a, 13b Ear canals 21a, 21b, 21c, 21d Filters 22a, 22b Adders 23a, 23b Filter 41a Left amplifier 41b Right amplifier 71 Personal computer 72 Amplifier 73 Speakers 74a, 74b Left and right microphones 74 Cylindrical structures 75a, 75b Amplifier 100 Car SW1 Changeover switch

Claims (2)

From binaural sounds generated by converting external sounds picked up by a pair of microphones attached to the outside of the sealed space by the head-related transfer function of the listener and sound sources attached to the inside of the sealed space In a sound collection switching device that switches and outputs stereo sound to be emitted,
A first cylindrical structure having a diameter substantially the same as a listener's head shape and mounted with the pair of microphones;
A crosstalk canceller that cancels a crosstalk signal generated when the binaural sound is output,
The crosstalk canceller has a filter storing a head-related transfer function obtained in advance, and the head-related transfer function picks up the external sound picked up by a pair of microphones attached to a second cylindrical structure prepared in advance. A sound collection switching device, which is a function obtained based on a crosstalk cancellation signal for sound. From binaural sounds generated by converting external sounds picked up by a pair of microphones attached to the outside of the sealed space by the head-related transfer function of the listener and sound sources attached to the inside of the sealed space In the sound collection switching method of switching and outputting stereo sound to be emitted,
Provided in the sealed space, having the same diameter as the listener's head shape, and mounting the pair of microphones on the first cylindrical structure;
Cancel the crosstalk signal that occurs when the binaural sound is output by the crosstalk canceller,
The external sound picked up by a pair of microphones using the head-related transfer function obtained using a second cylindrical structure prepared in advance for processing of a crotalk signal generated when the binaural signal is output. A sound pickup switching method characterized by obtaining a crosstalk cancellation signal for

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