JP2007081927A - Audio apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an audio apparatus capable of localizing a sound image with high sound quality to a rear side of a listener from speakers located in front of the listener. <P>SOLUTION: The audio apparatus 1 provides a frequency characteristic to an audio signal whereby the listener hears the audio signal localized on the rear side of the listener, direct correction sections 62, 66 and cross correction sections 64, 68 apply crosstalk cancel processing to the audio signal so as to be heard only by one ear of the listener U, and presence speakers 24, 25 located at positions higher than the height of the ears of the listener U output the sound of the resulting audio signal to the listener. When the presence speakers 24, 25 output sound for localizing sound images 26, 27 on the rear side of the listener, DIP caused in a higher frequency band of the audible frequency can be improved by about 5dB to 15dB more than the case with installation of the speakers at the same height as the ears of the listener U, and as the elevation angle increases, the frequency at which the DIP takes place can gradually be increased. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an audio device that localizes a sound image at a position different from a speaker installation position based on a head-related transfer function.

  Recently, multi-channel surround sound is played and reflected sound is generated from the sound of each channel. From the speaker for sound field formation installed at a position higher than the listener's ear on the front and rear sides of the listener. There is a sound field control device that allows a listener to enjoy a realistic sound by reproducing the reflected sound to form a plurality of sound fields (see, for example, Patent Document 1).

  However, in order for a listener to enjoy multichannel surround sound using the sound field control device described in Patent Document 1, a plurality of speakers must be installed around the listener, depending on the living environment. In some cases, it was not possible to install the speakers at the optimum position or to install all the speakers.

Therefore, even if a plurality of speakers are not installed around the listener, sound is emitted from the speakers installed on the front side of the listener, and a sound image is virtually localized around the listener (particularly on the rear side). An invention relating to a virtual speaker amplifier that provides a listener with an environment in which a multi-channel surround sound can be enjoyed has been proposed (see, for example, Patent Document 2).
Japanese Patent No. 2755208 Japanese Patent No. 3521900

  1A is a layout diagram of speakers installed at the height of the listener's ears and 30 degrees to the right of the listener, and FIGS. 1B to 1E are sounds with flat characteristics from the speakers. It is a graph which shows the frequency characteristic of the sound which sounded and was picked up with the dummy head.

  In the virtual speaker amplifier described in Patent Document 2, a characteristic that sounds can be heard from the rear side of the listener based on the head-related transfer function is given to the rear channel audio signal, and a crosstalk cancellation process is performed, so that the front of the listener By outputting this audio signal from the two front speakers installed in the, the sound image can be virtually localized on the rear side of the listener.

  However, when, for example, a flat characteristic sound is emitted from the speaker installed in front of the listener as described above and collected by the dummy head, as shown in FIGS. 1B and 1C, 9 kHz A large dip occurs in the vicinity. Therefore, as shown in FIGS. 1D and 1E, in the inverse filter generated to cancel the crosstalk, it is necessary to lift this dip portion greatly. However, when such a process is performed, a problem that the SN ratio of the middle and low range deteriorates occurs.

  On the other hand, in order to suppress the deterioration of the S / N ratio in the middle and low band, it is necessary to use an inverse filter that does not match the frequency characteristic in the high band. However, when such an inverse filter is used, there arises a problem that the sound quality in the high range is deteriorated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an audio device that can localize a sound image with good sound quality on the rear side of a listener from a speaker installed on the front side of the listener.

  The present invention has the following configuration as means for solving the above problems.

(1) An audio device for supplying a multi-channel audio signal including a rear channel to left and right front channel speakers installed in front of a listener and left and right presence speakers installed above the front channel speakers. ,
The left virtual localization is applied to the audio signal of the rear channel by calculating the frequency characteristic of the audio signal arriving at the listener's left ear from the virtual localization position in the rear direction based on the head-related transfer function and giving the audio signal And
A frequency characteristic for canceling a frequency characteristic of an audio signal arriving at the left ear of the listener from the left presence speaker is added to the audio signal processed by the left virtual localization providing unit based on a head-related transfer function. A left direct correction unit for supplying to the left presence speaker,
A frequency characteristic obtained by inverting the frequency characteristic of the audio signal that circulates from the left presence speaker to the right ear of the listener is added to the audio signal processed by the left virtual localization providing unit based on the head-related transfer function. A left cross correction unit that cancels an audio signal that wraps around the right ear by supplying the presence speaker on the right side;
For the rear channel audio signal, a right virtual localization is obtained by calculating a frequency characteristic of an audio signal arriving at a listener's right ear from a rearward virtual localization position based on a head-related transfer function and giving the audio signal A granting unit;
A frequency characteristic for canceling a frequency characteristic of an audio signal arriving at the right ear of the listener from the right presence speaker is added to the audio signal processed by the right virtual localization providing unit based on a head-related transfer function. Right direct correction unit to supply to the right presence speaker,
A frequency characteristic obtained by inverting the frequency characteristic of the audio signal that circulates from the right presence speaker to the listener's left ear is added to the audio signal processed by the right virtual localization providing unit based on the head-related transfer function. A right cross correction unit that cancels an audio signal that wraps around the left ear by supplying the left presence speaker;
It is provided with.

  When a sound that virtually localizes the sound image at a predetermined position is emitted from a front channel speaker installed in front of the listener, a large dip is generated in the vicinity of 9 kHz. Therefore, a reverse generated to cancel crosstalk is generated. In the filter, it is necessary to lift this dip portion greatly. However, when such processing is performed, the SN ratio in the middle and low range is deteriorated. On the other hand, it is necessary to use an inverse filter that does not match the frequency characteristics of the high band in order to suppress the deterioration of the S / N ratio in the middle and low band. If such an inverse filter is used, the sound quality of the high band deteriorates. To do.

  In this configuration, the audio device gives the audio signal a frequency characteristic that makes it sound as if the audio signal is localized at a predetermined position, and direct correction is performed so that this audio signal can only be heard from one ear of the listener. The crosstalk cancellation processing is performed by the means and the cross correction means, and the audio signal of the rear channel is emitted from the two presence speakers to the listener. Since the two presence speakers are installed above the front channel speakers installed in front of the listener, if the sound that localizes the sound image at a predetermined position is emitted from these presence speakers, Compared to the case where speakers are installed at the same height, the dip generated in the high frequency range of the audible frequency can be improved by about 5 dB to 15 dB, and the frequency at which the dip is generated gradually increases as the elevation angle increases. Can be high. Therefore, even if the crosstalk cancellation processing is performed, a sound image that emits a sound with a good sound quality can be prevented by preventing deterioration in the SN ratio of the mid-low range of the sound image localized at a predetermined position and deterioration of the sound quality of the high range. Can be localized in position. Furthermore, even if a speaker is not installed on the rear side of the listener, a sound image is virtually localized on the front side of the listener from a speaker disposed at a position higher than the listener's ear on the rear side of the listener. Therefore, the listener can enjoy the surround sound even in a living environment where a speaker cannot be installed on the rear side.

  The audio device of the present invention emits a sound for locating a sound image to the rear side from a front speaker installed at a position higher than the listener's ear, thereby generating a dip that occurs in a high frequency characteristic. The dip can be reduced while moving to a higher range of the audible frequency. Therefore, even if the crosstalk cancellation processing is performed, it is possible to prevent the deterioration of the S / N ratio of the mid-low range of the sound image localized at the rear side and the deterioration of the sound quality of the high range, and provide a surround sound with good sound quality.

  FIGS. 2 to 9 are views from the PRch speaker when the elevation angle of the PRch speaker is changed every 10 degrees in a range of 10 degrees to 80 degrees in the direction 30 degrees to the right of the listener U. It is the frequency characteristic graph of the filter set based on the head-related transfer function to a person's ear, and the frequency characteristic graph of the inverse filter. (A) of each figure is the frequency characteristic graph of the filter set based on the head-related transfer function from the PRch speaker to the listener's right ear, and (B) is the left ear of the listener from the PRch speaker. It is the frequency characteristic graph of the filter set based on the head-related transfer function until. (C) is a frequency characteristic graph of a direct correction filter for performing crosstalk cancellation processing, and (D) is a frequency characteristic graph of a cross correction filter for performing crosstalk cancellation processing. FIGS. 2 to 9 show the head transmission from the PRch speaker to the ear of the listener U when the PRch speaker is installed at an elevation angle of 0 degree in the direction 30 degrees to the right of the listener U. A frequency characteristic graph of the filter set based on the function is also shown for comparison.

  The inventors of the present application conducted experiments and studies on a method for suppressing the occurrence of the large dip. As a result, the inventors of the present application installed a loudspeaker that virtually emits a sound for locating the sound image at a position higher than the position of the ears EL and ER of the listener U, so that the above large dip It was discovered that the occurrence of can be suppressed.

  Specifically, as shown in FIGS. 2 to 9, as the elevation angle from the listening position 90 of the listener U to the PRch speaker 25 increases, the result is that the frequency at which the dip is gradually increased. It was. In addition, when the elevation angle was set to 10 degrees to 80 degrees with respect to the case where the elevation angle was 0 degrees, the dip was improved by about 5 dB to 15 dB. However, in the case of the elevation angle of 20 degrees, the frequency at which the dip occurs in the sound propagating from the PRch speaker 25 to the left ear EL is higher than that in the case of the elevation angle of 0 degree, but is deteriorated by about 5 dB.

  Therefore, in the present invention, two speakers are installed at a position higher than the ear of the listener U, preferably such that the angle of elevation from the listener U to the speaker is 30 degrees or more, and the audio device includes two speakers. The sound image is virtually localized at a specific position on the rear side of the listener U based on the inverse function of the head-related transfer function up to the ears EL and ER of the listener U. Thereby, even if the inverse filter of the frequency characteristic as shown in each of (C) and (D) of FIGS. 2 to 9 is used, the SN ratio in the middle and low frequencies is suppressed and the sound quality degradation in the high frequencies is suppressed. Thus, it is possible to localize a sound image that emits sound with good sound quality.

  The audio apparatus according to the present invention is configured based on the above-described experiment and examination results. From the left and right presence speakers installed at an elevation angle of 30 degrees or more above the listener, the rear of the listener U is provided. The sound of the SLch to which the frequency characteristic propagating from the left side to the ear of the listener U is given and the sound of the SRch to which the frequency characteristic propagating from the rear right side of the listener U to the ear of the listener U is given are emitted. As a result, the rear channel (SLch and SRch) sound images can be virtually localized behind the listener U, and the sound quality of the SLch and SRch sounds can be improved.

  FIG. 10 is a block diagram showing the configuration of the audio apparatus according to the embodiment of the present invention. In the following description, as an example, the case where the audio apparatus 1 reproduces 5-channel surround sound will be described. Here, for each of the five surround sound channels, the front left channel is L (Left) ch, the front right channel is R (Right) ch, the center channel is C (Center) ch, and the rear left channel is SL The (Surround Left) ch and the rear right channel are called SR (Surround Right) ch.

  The audio apparatus 1 includes a DSP (Digital Signal Processor) decoder 11, a signal processing unit 12, a D / A converter 13, a low-pass filter 14, an electronic volume 15, a power amplifier 16, a controller 17, a memory 18, an operation unit 19, and a display unit. 20 is provided. The power amplifier 16 of the audio apparatus 1 is connected to an Lch speaker 21, an Rch speaker 22, a Cch speaker 23, a PLch speaker 24, and a PRch speaker 25.

  As shown in FIG. 10, an Lch speaker 21, an Rch speaker 22, and a Cch speaker 23 are arranged in the room 91 as front speakers at the front left, front right, and front center of the listening position 90 of the listener U. ing. Further, it is a presence speaker for sound field control at the upper left front and upper right front (above the speakers 21, 22, 23) of the listener U, ie above the ears EL, ER of the listener U. A PLch speaker 24 and a PRch speaker 25 are arranged. The audio device 1 emits the reflected sound from the PLch speaker 24 and the PRch speaker 25 to give a depth feeling and a three-dimensional feeling in front of the listener U at the listening position 90, and wraps the listener U from the front. A field can be formed.

  A digital audio interface receiver (DIR) 32, an A / D converter 34, and a high definition multimedia interface (HDMI) (registered trademark) receiver 36 are connected to the DSP decoder 11. The DSP decoder 11 is an analog sound signal or digital bit output from an AV device such as the tuner 2 connected via the A / D converter 34 or the DVD player 3 connected via the HDMI (registered trademark) receiver 36. The stream is converted into a 5-channel digital sound signal (PCM signal) of Lch, Rch, Cch, SLch, and SRch and output to the signal processing unit 12. The DSP decoder 11 supports various data formats such as AAC (registered trademark), Dolby Digital (registered trademark), DTS (registered trademark), MPEG-1 / 2, MPEG-2 multi-channel, MP3, and the like. An external input signal is decoded into a 5-channel digital sound signal (PCM signal) by a decoder (not shown). For example, when a 5-channel digital sound signal (PCM signal) is directly input from the DVD player 3, the DSP decoder 11 outputs these signals to the signal processing unit 12 as they are.

  The signal processing unit 12 includes an SLch localization addition unit 42 including filters 42L and 42R, an SRch localization addition unit 46 including filters 46L and 46R, adders 52 and 53, and an Lch direct correction that constitutes a crosstalk cancellation correction unit 60. A unit 62, an Lch cross correction unit 64, an Rch direct correction unit 66, an Rch cross correction unit 68, and adders 72 and 73. Here, the DSP decoder 11 and the signal processing unit 12 may be constituted by one DSP or different DSPs.

  The signal processing unit 12 allows the listener U to hear the SLch sound image 26 localized at a point 26A on the left rear side of the listener U, and the listener U receives the SRch sound image 27 behind the listener U. Signal processing is performed so that the sound is localized at the point 27A on the right side.

  Specifically, each unit of the signal processing unit 12 performs the following operation. The SLch localization adding unit 42 includes the filter 42L and the filter 42R as described above. The filter 42L is set with a filter coefficient and a delay time based on the head-related transfer function from the sound image localized on the left rear side of the listener U to the left ear EL of the listener U, and the filter 42R is set behind the listener U. A filter coefficient based on the head-related transfer function from the sound image localized on the left side to the right ear ER of the listener U and a delay time are set. The SLch localization adding unit 42 has frequency characteristics that the listener U at the listening position 90 can hear in the left ear EL and the right ear ER so that the SLch sound image 26 is localized at a point 26A on the left rear side of the listener U. It is given to the audio signal of SLch.

  In addition, the SRch localization adding unit 46 includes the filter 46L and the filter 46R as described above. The filter 46L is set with a filter coefficient and a delay time based on the head-related transfer function from the sound image localized on the right rear side of the listener U to the left ear EL of the listener U, and the filter 46R is set behind the listener U. A filter coefficient based on a head-related transfer function from the sound image localized on the right side to the right ear ER of the listener U and a delay time are set. The SRch localization adding unit 46 has frequency characteristics that the listener U at the listening position 90 can hear in the left ear EL and the right ear ER so that the SRch sound image 27 is localized at a point 27A on the rear right side of the listener U. This is added to the SRch audio signal.

  The audio signals output from the filters 42L and 46L are added by the adder 52 and output to the Lch direct correction unit 62 and the Lch cross correction unit 64 of the crosstalk cancellation correction unit 60. The audio signals output from the filters 42R and 46R are added by the adder 53 and output to the Rch direct correction unit 66 and the Rch cross correction unit 68 of the crosstalk cancellation correction unit 60.

  Here, when a sound having a flat frequency characteristic is emitted to the listener U from, for example, a PRch speaker 25 installed at an elevation angle of 30 degrees, each frequency component of the sound reaching the right ear ER of the listener U is attenuated. Thus, the frequency characteristics as shown in FIG. Further, the sound that reaches the left ear EL of the listener U from the PRch speaker 25 has frequency characteristics as shown in FIG. Therefore, the listener U can unconsciously judge that the sound is emitted from the speaker 22 because the sound having such frequency characteristics arrives at the ears EL and ER of the listener U with a certain time difference.

  On the other hand, with respect to the SRch audio signal, the frequency characteristics of the sound that is emitted from the sound source localized at the rear right side of the listener U and reaches the ear of the listener U, and the sound that is emitted from the PRch speaker 25 and listened to the listener When a frequency characteristic that cancels the frequency characteristic of the sound that reaches the right ear ER of U is applied based on the head-related transfer function and emitted from the PRch speaker 25, the listener U receives the sound from the rear right side. I feel like I can hear it. At this time, the sound that is emitted from the PRch speaker 25 and is transmitted to the left ear of the listener U so that the sound emitted from the PRch speaker 25 can be heard only by the right ear of the listener U. And the sound is emitted from the PLch speaker 24, the listener U does not perceive that the SRch sound is emitted from the PRch speaker 25.

  Therefore, the crosstalk cancellation correction unit 60 allows the sound emitted from the PRch speaker 25 to be heard from the right of the listener U so that the sound emitted from the PLch speaker 24 can be heard only by the left ear EL of the listener U. A crosstalk cancellation process for generating a sound that cancels the sound heard by the ear on the opposite side so that it can be heard only by the ear ER is performed.

  Specifically, each unit of the crosstalk cancellation correction unit 60 performs the following processing / operation. FIG. 11 is a conceptual diagram for explaining the crosstalk cancellation processing and a block diagram showing details of the crosstalk cancellation correction unit.

  In FIG. 11A, the head-related transfer function of the left ear EL of the listener U from the PLch speaker 24 and the head-related transfer function of the right ear ER of the listener U from the PRch speaker 25 are fd, and the PLch speaker 24 The head transfer function of the right ear ER of the listener U and the head transfer function of the left ear EL of the listener U from the PRch speaker 25 are denoted by fc.

In the Rch direct correction unit 66, a filter coefficient corresponding to the inverse function of the head-related transfer function from the PRch speaker 25 to the right ear ER of the listener U is set. That is, as shown in FIG. 11B, the filter coefficient fd / (fd ² −fc ² ) is set in the Rch direct correction unit 66.

  The Rch direct correction unit 66 performs a process of erasing the characteristic of propagating from the PRch speaker 25 to the right ear ER on the rear channel audio signal output from the adder 53, and the rear channel audio sound is converted to the PRch speaker. It is possible to prevent the listener U from perceiving that the sound is emitted from 25. For example, when the PRch speaker 25 is installed at a position with an elevation angle of 30 degrees with respect to the right ear ER of the listener U, the Rch direct correction unit 66 converts the SRch audio signal into the SRch audio signal output from the PRch speaker 25. On the other hand, the frequency characteristics shown in FIG.

  Therefore, when the rear channel audio sound is emitted from the PRch speaker 25 and propagates to the right ear ER of the listener U, each frequency component is attenuated, but the Rch direct correction unit 66 raises the level by the attenuation amount in advance. The As a result, the rear channel audio signal output from the Rch direct correction unit 66 has a frequency characteristic applied by the localization adding units 42 and 46 and a frequency characteristic that cancels the characteristic of propagation from the PRch speaker 25 to the right ear ER. , Will have.

Further, the Rch cross correction unit 68 includes an inverse function of the head-related transfer function from the PRch speaker 25 to the listener's U right ear ER and the head transfer from the PLch speaker 24 to the listener's U left ear EL. A filter coefficient corresponding to the product of the inverse function and the function is set. That is, as shown in FIG. 11 (B), the filter coefficient fc / (fd ² −fc ² ) is set in the Rch cross correction unit 68.

  The Rch cross correction unit 68 cancels the characteristics of the rear channel audio signal output from the adder 53 from propagating from the PRch speaker 25 to the right ear ER, and propagates from the PLch speaker 24 to the left ear EL. And canceling the characteristic to be performed. For example, when the PRch speaker 25 is installed at a position with an elevation angle of 30 degrees with respect to the right ear E of the listener U, the Rch direct correction unit 66 outputs the rear channel audio output from the PRch speaker 25. A frequency characteristic shown in FIG. 4D is given to the signal. The Rch cross correction unit 68 performs the above processing on the rear channel audio signal output from the adder 53, adds the phase in the buffer 69 by the inversion / adder 72, and emits the sound from the PLch speaker 24. The timing at which the rear-channel audio signal propagates to the left ear EL of the listener U and the rear-channel audio signal processed by the Rch direct correction unit 66 and emitted from the PRch speaker 25 to the left ear EL of the listener U The output timing of the rear channel audio signal is adjusted so that the propagation timing is the same. Therefore, the audio device 1 emits the audio sound from the PRch speaker 25 because the audio sound that is emitted from the PRch speaker 25 and cancels the audio sound that wraps around the left ear EL of the listener U is emitted from the PLch speaker 24. Thus, it is possible to prevent the audio sound that wraps around the left ear EL of the listener U from being heard.

  Similarly to the Rch direct correction unit 66 and the Rch cross correction unit 68, the Lch direct correction unit 62 and the Lch cross correction unit 64 perform signal processing on the rear channel audio signal output from the adder 52.

  Thus, the rear channel audio sound emitted from the PLch speaker 24 can be heard only by the listener U's left ear EL, and the rear channel audio sound emitted from the PRch speaker 25 can be heard from the listener U's right. It becomes audible only to the ear ER. The rear channel audio signal is given a frequency characteristic so that a sound image is virtually localized around the listener U. Further, the rear channel audio sound emitted from the PLch speaker 24 is given a frequency characteristic so as not to perceive that the sound is emitted from the PLch speaker 24, and is emitted from the PRch speaker 25. The rear channel audio sound is given a frequency characteristic so as not to perceive that the sound is emitted from the PRch speaker 25. Accordingly, the listener U can obtain a sense of localization such that the audio sound of the rear channel is emitted from a sound source that is localized at a predetermined position around the listener U.

  The adder 72 adds the audio signal output from the Lch direct correction unit 62 and the audio signal output from the Rch cross correction unit 68 and inverted (multiplied by −1) by the buffer 69 to add D / Output to the A converter 13.

  The adder 73 adds the audio signal output from the Rch direct correction unit 66 and the audio signal output from the Lch cross correction unit 64 and inverted (multiplied by −1) by the buffer 65 to obtain D / Output to the A converter 13.

  The D / A converter 13 converts the digital sound signals of a total of five channels of Lch, Rch, Cch, SLch, and SRch output from the signal processing unit 12 into analog sound signals, respectively.

  The low-pass filter 14 removes aliasing noise in a band of 20 kHz or higher from each analog sound signal.

  The electronic volume 15 adjusts the signal amount of the analog sound signal of each channel based on the control signal output from the controller 17 according to the operation of the operation unit 19.

  The power amplifier 16 amplifies the analog sound signal adjusted by the electronic volume 15 and outputs it to the speakers 21 to 25.

  The speakers 21 to 25 emit sound corresponding to the analog sound signal output from the power amplifier 16. That is, the speaker 21 emits Lch sound, the speaker 22 emits Cch sound, and the speaker 23 emits Rch sound. Further, the speaker 24 emits a sound that virtually positions the SLch sound image at the point 26A, and the speaker 25 emits a sound that virtually positions the SRch sound image at the point 27A.

  The controller 17 controls each unit in accordance with the operation performed on the operation unit 19. For example, when a volume adjustment operation is performed on the operation unit 19, the controller 17 outputs a control signal corresponding to this operation to the electronic volume 15 to change the volume of the sound emitted from each speaker 21 to 25. The controller 17 is preferably a CPU or MPU.

  The memory 18 stores a program executed by the controller 17.

  The operation unit 19 is used by the user to input various operations and settings to the audio apparatus 1.

  The display unit 20 is for displaying items transmitted from the audio device 1 to the user.

  When reproducing the surround sound, the audio apparatus 1 configured as described above emits sound based on the Lch audio signal from the Lch speaker 21 and is based on the Rch audio signal from the Rch speaker 22. The sound is emitted, and the sound based on the Cch audio signal is emitted from the Cch speaker 23. In addition, the audio device 1 allows the listener U to hear the SLch sound image 26 localized at a point 26A on the left rear side of the listener U, and the listener U receives the SRch sound image 27 of the listener U. The sound based on the SLch audio signal and the SRch audio signal is emitted from the PLch speaker 24 and the PRch speaker 25 so that the sound is localized at the point 27A on the right rear side.

  As described above, the audio apparatus 1 is configured so that the listener can listen to the sound image so that the sound image is virtually localized on the rear side of the listener U from the presence speaker installed at an elevation angle of 30 degrees or more with respect to the listener U. Based on the head-related transfer function up to the ear, the audio signal is given a characteristic to emit sound. The sound image to be played can be localized.

  In addition, although the case where the sound image is virtually localized on the rear side of the listener U using the presence speaker installed in front of the listener U has been described, the present invention is not limited to this, and other configurations It may be. For example, a speaker hung from the ceiling or embedded in the ceiling can be used.

  Moreover, although the case where only the sound for virtually locating the sound image is emitted from the presence speaker to the rear side of the listener U has been described, the present invention is not limited to this, and the reflected sound for forming the front sound field At the same time, sound can be emitted from the presence speaker. As a result, a sound field that surrounds the listener U is generated by emitting the reflected sound for forming the front sound field from the presence speaker and the reflected sound for virtually forming the surround sound field. It is also possible to do.

(A) is the height of the listener's ear, the layout of the speaker installed 30 degrees to the right of the listener, and (B) to (E) emitting flat sound from the speaker. 5 is a graph showing frequency characteristics of sound collected by a dummy head. It is the frequency characteristic graph of a filter at the time of installing the speaker for PRch at an elevation angle of 10 degree | times, and the frequency characteristic graph of the reverse filter. It is the frequency characteristic graph of a filter at the time of installing the speaker for PRch at an elevation angle of 20 degree | times, and the frequency characteristic graph of the reverse filter. It is the frequency characteristic graph of the filter at the time of installing the speaker for PRch at an elevation angle of 30 degree | times, and the frequency characteristic graph of the reverse filter. It is the frequency characteristic graph of a filter at the time of installing the speaker for PRch at an elevation angle of 40 degree | times, and the frequency characteristic graph of the reverse filter. It is the frequency characteristic graph of the filter at the time of installing the speaker for PRch at an elevation angle of 50 degree | times, and the frequency characteristic graph of the reverse filter. It is the frequency characteristic graph of the filter at the time of installing the speaker for PRch at an elevation angle of 60 degree | times, and the frequency characteristic graph of the reverse filter. It is the frequency characteristic graph of a filter at the time of installing the speaker for PRch at an elevation angle of 70 degree | times, and the frequency characteristic graph of the reverse filter. It is the frequency characteristic graph of a filter at the time of installing the speaker for PRch at an elevation angle of 80 degree | times, and the frequency characteristic graph of the reverse filter. It is a block diagram which shows the structure of the audio apparatus which concerns on embodiment of this invention. It is the conceptual diagram for demonstrating a crosstalk cancellation process, and the block diagram which shows the detail of a crosstalk cancellation correction | amendment part.

Explanation of symbols

    1-acoustic device, 11-DSP decoder, 12-signal processing unit, 13-D / A converter, 14-low pass filter, 15-electronic volume, 16-power amplifier, 17-controller, 18-memory, 19-operation unit 20-display unit, 21-Lch speaker, 22-Rch speaker, 23-Cch speaker, 24-PLch speaker, 25-PRch speaker, 26, 27-virtual sound image, 42-SLch localization adding unit, 46-SRch localization addition unit, 60-crosstalk cancellation correction unit, 62-Lch direct correction unit, 64-Lch cross correction unit, 66-Rch direct correction unit, 68-Rch cross correction unit, 52, 53, 72, 73 -Adder

Claims (1)

An audio device for supplying a multi-channel audio signal including a rear channel to left and right front channel speakers installed in front of a listener, and left and right presence speakers installed above the front channel speaker,
The left virtual localization is applied to the audio signal of the rear channel by calculating the frequency characteristic of the audio signal arriving at the listener's left ear from the virtual localization position in the rear direction based on the head-related transfer function and giving the audio signal And
A frequency characteristic for canceling a frequency characteristic of an audio signal arriving at the left ear of the listener from the left presence speaker is added to the audio signal processed by the left virtual localization providing unit based on a head-related transfer function. A left direct correction unit for supplying to the left presence speaker,
A frequency characteristic obtained by inverting the frequency characteristic of the audio signal that circulates from the left presence speaker to the right ear of the listener is added to the audio signal processed by the left virtual localization providing unit based on the head-related transfer function. A left cross correction unit that cancels an audio signal that wraps around the right ear by supplying the presence speaker on the right side;
For the rear channel audio signal, a right virtual localization is obtained by calculating a frequency characteristic of an audio signal arriving at a listener's right ear from a rearward virtual localization position based on a head-related transfer function and giving the audio signal A granting unit;
A frequency characteristic for canceling a frequency characteristic of an audio signal arriving at the right ear of the listener from the right presence speaker is added to the audio signal processed by the right virtual localization providing unit based on a head-related transfer function. Right direct correction unit to supply to the right presence speaker,
A frequency characteristic obtained by inverting the frequency characteristic of the audio signal that circulates from the right presence speaker to the listener's left ear is added to the audio signal processed by the right virtual localization providing unit based on the head-related transfer function. A right cross correction unit that cancels an audio signal that wraps around the left ear by supplying the left presence speaker;
An audio device comprising:

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