JP7061037B2 - Sound field reproduction system, sound field reproduction method and sound field reproduction program - Google Patents

Description

The present invention relates to a sound field reproduction system, a sound field reproduction method, and a sound field reproduction program.

A sound field reproduction system that reproduces a sound field using a plurality of speakers is known. For example, Patent Document 1 describes a specific configuration of this type of sound field reproduction system.

The sound field reproduction system described in Patent Document 1 controls the sound pressure in the low frequency range of sound information by using a large-diameter indoor speaker installed in each door or the like, and also controls a small sound pressure installed in the headrest or the like of each seat. By controlling the sound pressure in the mid-high range of sound information using a speaker in the vicinity of the caliber, it is configured to reproduce a sound field with little deterioration in accuracy over the entire frequency band in each seat in the vehicle interior. ..

Japanese Unexamined Patent Publication No. 2007-19940

In the vehicle interior, for example, voice guidance by a navigation device may be superimposed and played while a song is being played by an audio device. In this case, it is desirable that the driver sitting in the driver's seat preferentially listens to the voice guidance by the navigation device, and it is desirable that the passenger sitting in the back seat preferentially listens to the music by the audio device.

Therefore, using the sound field reproduction system, one of the multiple types of sound information such as music and voice guidance can be independently listened to at each seat in the vehicle interior. By controlling the sound pressure, for example, it is conceivable to reproduce in the vehicle interior a sound field in which only voice guidance can be heard in the driver's seat and only music can be heard in the rear seat. .. However, the sound field reproduction system described in Patent Document 1 has a configuration specialized in controlling the sound pressure of a single sound information with high accuracy. Therefore, in the sound field reproduction system described in Patent Document 1, it is difficult to accurately control the sound pressure of a plurality of types of sound information.

The present invention has been made in view of such circumstances, and an object of the present invention is to enable independent listening to one of a plurality of types of sound information in each of a plurality of areas. It is to provide a sound field reproduction system, a sound field reproduction method, and a sound field reproduction program capable of accurately controlling the sound pressure of a plurality of types of sound information.

The sound field reproduction system according to the embodiment of the present invention includes a first filter and a second filter that limit a plurality of types of sound information to different frequency bands, a plurality of types of sound information that has passed through the first filter, and a second filter. Of the plurality of types of sound information that has passed through the filter, at least a plurality of first speakers that emit the former sound information to a plurality of areas, and a plurality of types that emit a plurality of types of sound information that has passed through the second filter to a plurality of areas. The storage unit stores a plurality of pairs of the transfer function of the first filter and the transfer function of the second filter, and the storage unit receives an input for designating the sound field to be reproduced. It includes an application unit that selects a set of transfer functions according to an input from a plurality of stored sets of transfer functions and applies them to the first filter and the second filter. The transfer function of the paired first filter and the transfer function of the second filter set at least one first control point for the first frequency band in each of the plurality of areas and are higher than the first frequency band. A larger number of second control points for the second frequency band can be set than the first control point, and one of a plurality of types of sound information can be independently listened to in each of the plurality of areas. It is set to a value for controlling the sound pressure of a plurality of types of sound information at each first control point and each second control point. In the sound field reproduction system, when a set of transfer functions is applied to the first filter and the second filter by the application unit, a plurality of areas are provided by a plurality of types of sound information emitted from each first speaker and each second speaker. It is a sound field that enables independent listening to one of a plurality of types of sound information in each of the above, and reproduces the sound field specified by the input.

Of the plurality of first speakers and the plurality of second speakers, the number of speakers that contribute to the setting of the second control point may be larger than that of the speakers that contribute to the setting of the first control point.

The speaker that contributes to the setting of the second control point emits sound information including, for example, a second frequency band higher than at least the first frequency band.

The first filter limits, for example, a plurality of types of sound information to the first frequency band. The second filter limits, for example, a plurality of types of sound information to the second frequency band.

The sound field reproduction system may further include an equalizer unit that performs equalizer processing using the same parameter values for a plurality of types of sound information that has passed through the first filter and a plurality of types of sound information that has passed through the second filter. good.

The sound field reproduction system applies to the first gain section, which applies a gain with the same gain value to a plurality of types of sound information corresponding to each speaker, which has passed the first filter, and to each speaker, which has passed the second filter. A configuration may be further provided in which a second gain unit for applying a gain with the same gain value to the corresponding plurality of types of sound information is further provided.

The sound field reproduction method according to the embodiment of the present invention includes a first filter and a second filter that limit a plurality of types of sound information to different frequency bands, a plurality of types of sound information that has passed through the first filter, and a second. Of the plurality of types of sound information that has passed through the filter, at least a plurality of first speakers that emit the former sound information to a plurality of areas, and a plurality of types that emit a plurality of types of sound information that has passed through the second filter to a plurality of areas. 2nd speaker, a storage unit that stores a plurality of pairs of transmission functions of the 1st filter and a transmission function of the 2nd filter, and an input that specifies the sound field to be reproduced are received in the storage unit. A sound field is reproduced using a sound field reproduction system including a first filter and an application part to be applied to the second filter by selecting a set of transfer functions according to an input from a plurality of stored sets of transfer functions. A step of applying a set of transfer functions to the first filter and a second filter by an application unit, and a step of limiting a plurality of types of sound information to different frequency bands by the first filter and the second filter. At least the former includes a step of emitting sound information from a plurality of first speakers to a plurality of areas and a plurality of types of sound information that has passed through a second filter from a plurality of second speakers to a plurality of areas. The transfer function of the paired first filter and the transfer function of the second filter set at least one first control point for the first frequency band in each of the plurality of areas and are higher than the first frequency band. A larger number of second control points for the second frequency band can be set than the first control point, and one of a plurality of types of sound information can be independently listened to in each of the plurality of areas. It is set to a value for controlling the sound pressure of a plurality of types of sound information at each first control point and each second control point. In the emitting step, the sound information emitted from each first speaker and each second speaker makes it possible to independently listen to one of a plurality of types of sound information in each of the plurality of areas. It is a sound field, and the sound field specified by the input is reproduced.

The sound field reproduction program according to the embodiment of the present invention is a program for causing a computer to execute the above-mentioned sound field reproduction method.

According to one embodiment of the present invention, the sound pressure of a plurality of types of sound information is accurately controlled so that one of the plurality of types of sound information can be independently listened to in each of the plurality of areas. A possible sound field reproduction system, sound field reproduction method and sound field reproduction program are provided.

It is a block diagram which shows the structure of the sound field reproduction system which concerns on one Embodiment of this invention. In one embodiment of the present invention, a diagram showing a plurality of listening areas arranged in the vehicle interior (FIG. 2A), an installation position of each speaker in the vehicle interior, and a position of each control point set in the vehicle interior are shown. It is a figure (FIG. 2 (b)). It is a figure which shows the flowchart of the sound field measurement processing executed in the sound field reproduction system which concerns on one Embodiment of this invention. In one embodiment of the present invention, a diagram showing an impulse response (linear scale) for each speaker picked up by a microphone installed at a first control point in the listening area (driver's seat) (FIG. 4A). The figure (FIG. 4 (b)) showing the impulse response (decibel scale) for each speaker picked up by the microphone installed at the first control point in the listening area (driver's seat) and the inside of the listening area (driver's seat). It is a figure (FIG. 4C) which shows the amplitude characteristic of the impulse response for each speaker picked up by the microphone installed in the 1st control point. In one embodiment of the present invention, a diagram showing an impulse response (linear scale) for each speaker picked up by a microphone installed at one of a pair of second control points in the listening area (driver's seat) (FIG. 5 (FIG. 5). a)), a diagram showing an impulse response (decibel scale) for each speaker picked up by a microphone installed at one of a pair of second control points in the listening area (driver's seat) (FIG. 5 (b)). It is a figure (FIG. 5 (c)) which shows the amplitude characteristic of the impulse response for each speaker picked up by the microphone installed in one of the pair of 2nd control points in a listening area (driver's seat). In one embodiment of the present invention, a diagram showing an impulse response (linear scale) for each speaker picked up by a microphone installed at the other of a pair of second control points in the listening area (driver's seat) (FIG. 6 (FIG. 6). a)), a diagram showing an impulse response (decibel scale) for each speaker picked up by a microphone installed at the other of a pair of second control points in the listening area (driver's seat) (FIG. 6 (b)). It is a figure (FIG. 6 (c)) which shows the amplitude characteristic of the impulse response for each speaker picked up by the microphone installed in the other of the pair of 2nd control points in a listening area (driver's seat). It is a block diagram which shows the structure of the signal processing part of the sound field reproduction apparatus provided in the sound field reproduction system which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of the multi-point sound pressure control part provided in the signal processing part which concerns on one Embodiment of this invention. In one embodiment of the present invention, a diagram showing an impulse response reproduced at a first control point in a listening area (driver's seat) when two types of sound information are emitted from a speaker in a vehicle interior (FIG. 9A). 9 (b) and FIGS. 9 (c) and 9 (d) show the amplitude characteristics thereof. In one embodiment of the present invention, a diagram showing an impulse response reproduced at one of a pair of second control points in the listening area (driver's seat) when two types of sound information are emitted from a speaker in the vehicle interior (FIG.). 10 (a) and 10 (b)) and the figure (FIG. 10 (c) and FIG. 10 (d)) showing the amplitude characteristic thereof. In one embodiment of the present invention, a diagram showing an impulse response reproduced at the other of a pair of second control points in the listening area (driver's seat) when two types of sound information are emitted from a speaker in the vehicle interior (FIG.). 11 (a) and 11 (b)) and a diagram (FIG. 11 (c) and FIG. 11 (d)) showing the amplitude characteristics thereof. It is a figure which shows the characteristic of the audio signal of two kinds of sound information emitted from the speaker in the vehicle interior in one Embodiment of this invention. It is a figure which shows the acoustic characteristic obtained in the listening area (driver's seat) when two kinds of sound information are emitted from the speaker in the vehicle interior in one Embodiment of this invention. It is a figure which shows the acoustic characteristic obtained in the listening area (right rear seat) when two kinds of sound information are emitted from the speaker in the vehicle interior in one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, as an embodiment of the present invention, a sound field reproduction system installed in a vehicle interior will be described as an example.

FIG. 1 is a block diagram showing a configuration of a sound field reproduction system 1 according to an embodiment of the present invention. In the sound field reproduction system 1 according to the present embodiment, each sound pressure of a plurality of types of sound information emitted from a plurality of speakers installed in the vehicle interior is set to a desired value at each control point in the vehicle interior. It is a system that controls the sound pressure of an audio signal (a signal that reproduces sound information) output from a speaker and reproduces a desired sound field in a listening environment such as a vehicle interior.

As shown in FIG. 1, the sound field reproduction system 1 includes a sound field reproduction device 100 and a plurality of speakers SP. The sound field reproduction device 100 includes a control unit 102, a display unit 104, an operation unit 106, a measurement signal generation unit 108, a channel selection unit 110, a D / A converter 112, a power amplifier 114, a microphone amplifier 116, and an A / D converter 118. , A storage unit 120, a coefficient calculation unit 122, a signal processing unit 124, and a gain unit 126. In FIG. 1, the connection between the control unit 102 and other components is appropriately omitted for the sake of avoiding the complexity of the drawing.

The plurality of types of sound information means a plurality of sound information having different sound sources, for example, voice guidance by a navigation device, music by an audio device, radio broadcasting, and an information processing terminal wirelessly connected to a sound field reproduction device 100 ( It includes at least two sound information such as telephone voice from a tablet, smartphone, etc.), voice on the Internet, mixed sound information, and the like. The mixed sound information is a sound source in which a plurality of sound information is mixed (for example, a mixture of voice guidance and music). It should be noted that the sound information of the same type of device but different sound sources, such as the voice of each of the plurality of information processing terminals, is also included in the plurality of types of sound information.

The sound field reproduced by the sound field reproduction system 1 makes it possible to independently listen to one of a plurality of types of sound information in each of a plurality of listening areas arranged in a closed space such as a vehicle interior. It is a sound field. In the present embodiment, the plurality of listening areas are seats in the vehicle interior such as a driver's seat, a passenger seat, and a rear seat. According to the sound field reproduction system 1, for example, it is possible to reproduce a sound field in which only voice guidance can be heard substantially in the driver's seat and only music can be heard in the rear seat.

The various processes in the sound field reproduction system 1 are executed by the cooperation of the software and the hardware provided in the sound field reproduction system 1. At least the OS (Operating System) part of the software provided in the sound field reproduction system 1 is provided as an embedded system, but other parts, for example, a software module for executing sound field measurement and sound field reproduction. May be provided as an application that can be distributed on a network or held on a recording medium such as a memory card. That is, the sound field measurement function and the sound field reproduction function according to the present embodiment may be functions built in advance in the sound field reproduction system 1 or may be functions that can be added via a network or a recording medium. ..

A reproduction device 200 is connected to the sound field reproduction device 100. The playback device 200 is, for example, an information processing terminal such as a navigation device, an audio device, a tablet, or a smartphone. In FIG. 1, the reproduction device 200 is shown as one device, but there may be a plurality of reproduction devices 200. A plurality of types of sound information such as voice guidance, music, telephone voice, radio broadcasting, and voice on the Internet output from the playback device 200 are input to the sound field reproduction device 100.

FIG. 2A shows a plurality of listening areas (areas surrounded by broken lines, in other words, seats) arranged in the vehicle interior. The codes " _{C_FR} ", " _{C_FL} ", " _{C_RR} ", and " _{C_RL} " are added to the listening areas of the driver's seat, passenger seat, right rear seat, and left rear seat, respectively.

FIG. 2B shows the installation position of each speaker SP and the position of each control point set in the vehicle interior. The speaker SP installed on the right door of the driver's seat is given the code " _{S_FR} ", and the speaker SP installed on the left door of the passenger seat is given the code " _{S_FL} ". The code " _{S_RR} " is attached to the speaker SP installed on the right door portion of the seat, and the code " _{S_RR} " is attached to the speaker SP installed on the left door portion of the left rear seat.

In this way, each speaker S_F _R , _{S_FL} , _{S_RR} , _{S_RL} is installed in the door portion outside each listening area, and in the sound field reproduction system 1, a plurality of types of sounds are used in each of the plurality of listening areas. When reproducing a sound field that allows one of the information to be heard independently, the low and mid-high frequencies are emitted. In the present embodiment, the speakers S_F _R , _{S_F L} , _{S_RR} , and _{S_RL} are installed outside the listening area, but in another embodiment, the speakers _{S_FR} , S_F _L , _{S_RR} , and S_RL are installed inside the listening area. It may be installed in.

The speakers S_F _R , S_F _L , _{S_RR} , and _{S_RL} have at least the former sound information in a plurality of areas among the plurality of types of sound information that has passed through the first filter and the plurality of types of sound information that has passed through the second filter. It is a specific example of a plurality of first speakers that emit (details will be described later). Hereinafter, these speakers S_F _R , _{S_FL} , _{S_RR} and _{S_RL} are collectively referred to as a “first speaker group”.

The code "S_F _Rr " is attached to the speaker SP installed on the right side of the headrest of the driver's seat, and the code "S_F _Rl " is attached to the speaker SP installed on the left side of the headrest of the driver's seat. The code "S_F _Lr " is attached to the speaker SP installed on the right side of the headrest of the passenger seat, and the code "S_F _Ll " is attached to the speaker SP installed on the left side of the headrest of the passenger seat. The code "S_R _Rr " is attached to the speaker SP installed on the right side of the headrest, and the code "S_R _Rl " is attached to the speaker SP installed on the left side of the headrest of the right rear seat. The code "S_R _Lr " is attached to the speaker SP installed at the position to the right of the headrest, and the code "S_R _Ll " is attached to the speaker SP installed at the position to the left of the headrest of the left rear seat.

As described above, each speaker S_F _Rr , S_F _Rl , S_F _Lr , S_F _Ll , S_R _Rr , S_R _Rl , S_R _Lr and S_R _Ll are installed in the headrest outside each listening area, and are installed in the sound field reproduction system 1. When reproducing a sound field that enables one of a plurality of types of sound information to be independently heard in each of a plurality of listening areas, the mid-high range is emitted. In the present embodiment, the speakers S_F _Rr , S_F _Rl , S_F _Lr , S_F _Ll , S_R _Rr , S_R _Rl , S_R _Lr and S_R _Ll are installed outside the listening area, but in another embodiment, the speakers S_F _Rr , S_F _Rl , S_F _Lr , S_F _Ll , S_R _Rr , S_R _Rl , S_R _Lr and S_R _Ll may be installed in the listening area.

Speakers S_F _Rr , S_F _Rl , S_F _Lr , S_F _Ll , S_R _Rr , S_R _Rl , S_R _Lr and S_R _Ll emit a plurality of types of sound information that has passed through the second filter to a plurality of areas (details will be described later). This is a specific example of the second speaker. Hereinafter, these speakers S_F _Rr , S_F _Rl , S_F _Lr , S_F _Ll , S_R _Rr , S_R _Rl , S_R _Lr and S_R _Ll are collectively referred to as "second speaker group".

In the sound field reproduction system 1, a total of 12 control points are set, three for each listening area. Specifically, one control point is set at the center position of each listening area, and a pair of control points are set at positions near the left and right ears of the listener sitting in each listening area. The positions of the pair of control points are, for example, positions determined by the designer who designs the sound field reproduction system 1 based on statistical information regarding the human physique and the like.

Hereinafter, the codes " _{M_FR} ", " _{M_FL} ", " _{M_RR} ", and " _{M_RL} " are added to the control points set at the center positions of the driver's seat, the passenger seat, the right rear seat, and the left rear seat, respectively. .. These control points _{M_FR} , _{M_FL} , _{M_RR} , and _{M_RL} are collectively referred to as "first control points". The first control point is a control point for low frequencies. At the first control point, when a plurality of types of sound information are emitted from each speaker SP, a desired sound pressure can be obtained for a low frequency portion of the plurality of types of sound information.

In the present embodiment, the low frequency portion of the plurality of types of sound information is emitted only from the first speaker group. Therefore, of the first speaker group and the second speaker group, only the first speaker group contributes to the setting of the first control point in each listening area.

In addition, the codes "M_F _Rr " and "M_F _Rl " are attached to the control points set near the right and left ears of the listener sitting in the driver's seat, respectively, and the right and left of the listener sitting in the passenger seat. The control points set near each ear are assigned the codes "M_F _Lr " and "M_F _Ll ", respectively, and are set near the right and left ears of the listener sitting in the right rear seat. The codes "M_R _Rr " and "M_R _Rl " are attached to the points, respectively, and the codes "M_R _Lr " and "M_R" are attached to the control points set near the right and left ears of the listener sitting in the left rear seat, respectively. " _Ll " is attached. These control points M_F _Rr , M_F _Rl , M_F _Lr , M_F _Ll , M_R _Rr , M_R _Rl , M_R _Lr and M_R _Ll are collectively referred to as "second control points". The second control point is a control point for the mid-high range, and has a larger number than the first control point. At the second control point, when a plurality of types of sound information are emitted from each speaker SP, a desired sound pressure can be obtained for the mid-high range portion of the plurality of types of sound information.

In the present embodiment, the mid-high range portion of a plurality of types of sound information is emitted from the first speaker group and the second speaker group. Therefore, all of the first speaker group and the second speaker group contribute to the setting of the second control point in each listening area.

In this way, the number of speaker SPs that emit the mid-high range portion of a plurality of types of sound information is larger than that of the speaker SP that emits the low-frequency portion of a plurality of types of sound information, and also contributes to the setting of the second control point. The number of speaker SPs to be used is larger than that of the speaker SPs that contribute to the setting of the first control point.

In the present embodiment, only the first speaker group emits a low frequency portion of a plurality of types of sound information, and both the first speaker group and the second speaker group emit a mid-high frequency portion of a plurality of types of sound information. However, the present invention is not limited to this. As an example, only the first speaker group may emit a low frequency portion of a plurality of types of sound information, and only the second speaker group may emit a mid-high frequency portion of a plurality of types of sound information. In this case as well, the number of speaker SPs that emit the mid-high range portion of a plurality of types of sound information is larger than that of the speaker SP that emits the low-frequency portion of a plurality of types of sound information, and also contributes to the setting of the second control point. The number of speaker SPs to be used is larger than that of the speaker SPs that contribute to the setting of the first control point.

If the desired sound pressure is obtained at the first control point and the second control point, the desired sound field is reproduced at least in the entire listening area. The control points (in other words, the microphone MIC described later) may be arranged in a layout that surrounds each listening area.

By changing the position and number of control points, the position, shape, and size of the listening area can be arbitrarily changed.

In order to reproduce the desired sound field in the vehicle interior (in other words, to obtain the desired sound pressure at each control point in the vehicle interior), it is first necessary to measure the sound field. When measuring the sound field, microphone MICs are installed at each control point in the vehicle interior.

In the present embodiment, one microphone MIC is installed at the center position (first control point) of each seat, and a pair of microphone MICs are installed at a predetermined position (second control point) of the headrest of each seat. Since there are four seats, a total of 12 microphone MICs will be installed in the passenger compartment.

The higher the frequency, the larger the phase shift of the sound information heard by the listener, for example, when the listener's head deviates from the position assumed by design. Therefore, in the present embodiment, in order to improve the accuracy of the sound pressure at the second control point targeting the mid-high range (priority is given to the accuracy of the sound pressure at the first control point targeting the low range). , The second control point is set more than the first control point. Specifically, in the present embodiment, four first control points are set, whereas eight second control points are set.

FIG. 3 is a diagram showing a flowchart of a sound field measurement process executed in the sound field reproduction system 1 according to the embodiment of the present invention. Various processes in the sound field reproduction system 1, including the sound field measurement process shown in this flowchart, are executed under the control of the control unit 102. When the control unit 102 receives a predetermined touch operation on the display unit 104 or a predetermined operation on the operation unit 106, the control unit 102 displays the sound field measurement condition input screen on the display unit 104. As a result, the sound field measurement process shown in this flowchart is started.

When the user inputs the sound field measurement condition to the input screen displayed on the display unit 102, the input sound field measurement condition is set (step S11). The sound field measurement condition input here is, for example, the number of channels (or designation of the speaker to be measured). Since the sound field reproduction system 1 according to the present embodiment is equipped with 12 speakers, the maximum number of channels that can be input is "12". In this embodiment, it is assumed that the number of channels of 12 is input.

In order to avoid the inconvenience of outputting unnecessary sound information from the speaker SP, the output signal from the signal processing unit 124 is muted in the gain unit 126 (step S12).

When the output signal from the signal processing unit 124 is muted, the channel corresponding to the speaker SP to be measured is set in the channel selection unit 110 (step S13).

When the channel corresponding to the speaker SP to be measured is set, a predetermined measurement signal is generated in the measurement signal generation unit 108 (step S14). The measurement signal is, for example, an M-sequence code (Maximal length sequence) or a TSP signal (Time Stretched Pulse), and is a speaker to be measured via the channel selection unit 110, the D / A converter 112, and the power amplifier 114. It is emitted from the SP as a sound for sound field measurement.

The sound for sound field measurement emitted from the speaker SP to be measured is picked up by all microphone MICs in the vehicle interior and input to the storage unit 120 via the microphone amplifier 116 and the A / D converter 118. In the storage unit 120, the impulse response is calculated and stored (step S15). For the impulse response, for example, the input sound field measurement sound and the reference measurement signal (TSP signal, etc.) are reversed on the time axis, and the reference signal having the opposite characteristic is Fourier transformed and multiplied on the frequency to be multiplied. It can be obtained by performing an inverse Fourier transform on the obtained value.

In step S16, it is determined whether or not the impulse response is stored for all the channels (speaker SP). If there is a channel for which the impulse response storage has not been completed (step S16: NO), the process of this flowchart returns to step S13.

The processes of steps S13 to S15 are executed for each channel set in step S13. In this embodiment, since 12 speaker SPs are set, the processes of steps S13 to S15 are repeated 12 times. When the processes of steps S13 to S15 are executed for all channels (step S16: YES), the mute by the gain unit 126 is released (step S17), and the sound field measurement process shown in this flowchart ends.

In another embodiment, the reproduction device 200 may generate a measurement signal. In this case, the measurement signal is output through the signal processing unit 124 and the gain unit 126 without the signal processing unit 124 and the gain unit 126 functioning, and is emitted as the sound field measurement sound from the speaker SP to be measured. ..

4 (a) and 4 (b) show a speaker (first control point for low frequencies) picked up by a microphone MIC installed at the control point _{M_FR} in the listening area _{C_FR} (driver's seat). The impulse response (linear scale) and the impulse response (decibel scale) for each control point _{M_FR} corresponding to the control point M_FR are shown. FIG. 4C shows the amplitude characteristics (frequency response) of the impulse response for each speaker picked up by the microphone MIC installed at the control point _{M_FR} . This frequency response is obtained, for example, by the FFT (Fast Fourier transform) unit 124A (described later) of the signal processing unit 124 performing a Fourier transform of the impulse response.

In FIG. 4 (a), the vertical axis shows the normalized amplitude (Amplitude), and the horizontal axis shows the time (Time (unit: s)). In FIG. 4B, the vertical axis represents power (Power (unit: dB)) and the horizontal axis represents time (Time (unit: s)). In FIG. 4 (c), the vertical axis indicates power (Power (unit: dB)), and the horizontal axis indicates frequency (Frequency (unit: Hz)). Power is the square of the amplitude. Also, human auditory characteristics are logarithmic to frequency. The horizontal axis of FIG. 4C is a logarithmic display according to the human auditory characteristics. 5 (a) to 5 (c) show the same diagram as in FIGS. 4 (a) to 4 (c) for the control point M_F _Rl . 6 (a) to 6 (c) show the same diagram as in FIGS. 4 (a) to 4 (c) for the control point M_F _Rr . In addition, in FIGS. 5 (a) to 5 (c) and FIGS. 6 (a) to 6 (c), the control points M_F _Rl and the control points M_F, which are the second control points for the mid-high range, are added. The impulse response for each first speaker and each second speaker corresponding to _Rr and their amplitude characteristics are shown.

FIG. 7 is a block diagram showing the configuration of the signal processing unit 124. As shown in FIG. 7, the signal processing unit 124 includes an FFT unit 124A, a multi-point sound pressure control unit 124B, an IFFT (Inverse Fast Fourier transform) unit 124C, and an EQ (Equalizer) unit 124D.

The audio signals of the plurality of types of sound information input from the reproduction device 200 are converted from the time domain to the frequency domain by the FFT unit 124A and output to the multipoint sound pressure control unit 124B. The audio signal in the frequency domain input to the multipoint sound pressure control unit 124B is filtered so that one of a plurality of types of sound information can be independently listened to in each listening area. The audio signal filtered by the multi-point sound pressure control unit 124B is converted from the frequency domain to the time domain by the IFFT unit 124C and output to the EQ unit 124D. The audio signal input to the EQ unit 124D is equalized and output to the gain unit 126.

Since the multi-point sound pressure control unit 124B performs filtering by multiplication in the frequency domain, the FFT by the FFT unit 124A and the IFFT by the subsequent IFFT unit 124C are calculated in consideration of linear convolution.

FIG. 8 is a block diagram showing the configuration of the multi-point sound pressure control unit 124B. As shown in FIG. 8, the multi-point sound pressure control unit 124B includes a first filtering unit 124Ba, a first gain unit 124Bb, a second filtering unit 124Bc, a second gain unit 124Bd, an uncontrolled band filtering unit 124Be, and a selector unit. It includes 124Bf, a third gain unit 124Bg, a channel connection unit 124Bh, and an addition unit 124Bi.

The audio signal in the frequency domain output from the FFT unit 124A is input to the first filtering unit 124Ba, the second filtering unit 124Bc, and the uncontrolled band filtering unit 124Be. The first filtering unit 124Ba passes through the low frequency portion of the audio signal, the second filtering unit 124Bc passes through the mid-high frequency region of the audio signal, and the uncontrolled band filtering unit 124Be passes through the uncontrolled band (first) of the audio signal. 1 A band other than the pass band of the filtering unit 124Ba and a band other than the pass band of the second filtering unit 124Bc) is passed.

The filter transfer function of the first filtering unit 124Ba and the second filtering unit 124Bc is calculated by the coefficient calculation unit 122.

The audio signal of the sound information reproduced at each control point Mi in the vehicle interior in the sound field to be reproduced is described as "X _i (ω)", and each control point M _k (k = ₎ in the vehicle interior in the actual reproduced sound field. The audio signal of the sound information reproduced in 1 to M) is described as "Y _k (ω)". When the system introduces a linear phase lag ∠φ (ω) that satisfies the causality, the relationship between the audio signal X _i (ω) to be reproduced and the audio signal Y _k (ω) to be reproduced is shown by the following equation 1. .. The input to the system is output from the system with some delay. When the sound information arrives at each control point with a different delay, the sound information observed at each control point is no longer different from the sound information originally desired to be reproduced, while the sound information is one at each control point. When it arrives with such a delay, the sound information observed at each control point can be regarded as the same as the sound information to be reproduced. In this embodiment, the latter uniform delay is expressed as "a linear phase delay in which the system satisfies causality".

(Equation 1)

It is assumed that the audio signal X _i (ω) is processed by the MN filters G _ij (ω) in the reproduced sound field, and the speaker SP _j (j = 1 to N) and the control point M _k (k = 1 to M). Assuming that the spatial transfer function of is H _jk (ω), the audio signal X _k (ω) ∠φ (ω) of the sound information reproduced at the control point M _k is expressed by the following equation 2.

(Equation 2)

The audio signal X _i (ω), the phase lag ∠φ (ω), and the spatial transfer function H _jk (ω) are all known. Specifically, the audio signal _Xi (ω) is a target value at the control point (a signal to be reproduced at the control point). The phase lag ∠φ (ω) is a value predetermined by a manufacturer such as a manufacturer of the sound field reproduction system 1 based on the results of tests and the like. The spatial transfer function H _jk (ω) is an amplitude characteristic of the impulse response exemplified in FIG. 4 (c) and the like. Strictly speaking, the amplitude characteristics of the spatial transfer function H _jk (ω) and the impulse response are different, but in the present embodiment, there is no problem even if they are identified with each _other . It is regarded as ω).

Since the audio signal X _i (ω), the phase lag ∠φ (ω), and the spatial transfer function H _jk (ω) are known, the coefficient calculation unit 122 can use the filter G _ij (filter transfer function) from Equation 2 above. ω) can be calculated. The filter _Gij (ω) calculated by the coefficient calculation unit 122 is stored in the storage unit 120.

In the present embodiment, audio signals of two types of sound information are input from the reproduction device 200 to the sound field reproduction device 100. Hereinafter, each of the two types of sound information will be referred to as sound information Src1 and Src2. In the present embodiment, as an example, a sound field in which only the sound information Src1 can be heard substantially in the driver's seat and the passenger seat, and the sound field in which only the sound information Src2 can be heard substantially in the right rear seat and the left rear seat is reproduced. do. In this case, when the above equation 2 is applied to the first control points _{M_FR} , _{M_FL} , _{M_RR} , and _{M_RL} targeting the low frequency range, it is as shown in the following equation 3. By operating the operation unit 106, the user can arbitrarily specify which sound information can be independently heard in which seat (that is, the sound field to be reproduced).

但し、

(Equation 3)

however,

In the storage unit 120, for example, the filter _Gij (ω) calculated by using the above equation 3 is stored. Hereinafter, for convenience, the filter G _ij (ω) exemplified by the above equation 3, that is, the filter G obtained by calculating the first control points _{M_FR} , _{M_FL} , _{M_RR} , and _{M_RL} for the low frequency range. _ij (ω) is referred to as “low frequency filter G _ij (ω)”.

The storage unit 120 also stores a mid-high range filter _Gij (ω) paired with a low-pass filter _Gij (ω). The "mid-high range filter G _ij (ω)" is calculated for the second control points M_F _Rr , M_F _Rl , M_F _Lr , M_F _Ll , M_R _Rr , M_R _Rl , M_R _Lr and M_R _Ll for the mid-high range. The obtained filter _Gij (ω). In the present embodiment, the paired low-frequency filter Gij (ω) and mid-high frequency filter Gij (ω) are applied to the first filtering unit 124Ba and the second filtering unit 124Bc, respectively, so that the driver's seat and the driver's seat and the driver's seat and the second filtering unit 124Bc are applied. It is possible to reproduce a sound field in which substantially only the sound information Src1 can be heard in the passenger seat and substantially only the sound information Src2 can be heard in the right rear seat and the left rear seat.

In the storage unit 120, for each sound field to be reproduced (for example, in the driver's seat and the passenger's seat, substantially only the sound information Src1 can be heard, and in the right rear seat and the left rear seat, substantially only the sound information Src2 can be heard. A pair of low-frequency filters for the field, driver's seat, and passenger's seat, where only sound information Src2 can be heard, and in the right rear seat and left rear seat, only sound information Src1 can be heard. A set of Gij (ω) and a mid-high range filter Gij (ω) is stored. Under the control of the control unit 102, a set of a low-frequency filter Gij (ω) and a mid-high frequency filter Gij (ω) corresponding to the sound field specified by the operation unit 106 is selected from a plurality of sets and selected. The low-frequency filter Gij (ω) and the mid-high frequency filter Gij (ω) are applied to the first filtering unit 124Ba and the second filtering unit 124Bc, respectively.

As an example, the first filtering unit 124Ba passes an audio signal of 30 Hz or more and less than 200 Hz. As an example, the second filtering unit 124Bc passes an audio signal of 200 Hz or more and less than 4000 Hz. The uncontrolled band filtering unit 124Be passes an audio signal of 4000 Hz or higher as an example. As described above, since the first filtering unit 124Ba and the second filtering unit 124Bc consider the linear phase delay in which the system satisfies the causality, the audio signal passing through the uncontrolled band filtering unit 124Be is also included in the audio signal. A delay equivalent to that of an audio signal passing through the first filtering unit 124Ba and the second filtering unit 124Bc is given.

The low-frequency audio signal that has passed through the first filtering unit 124Ba is amplified by the first gain unit 124Bb. The first gain unit 124Bb is provided with output ends of four channels corresponding to each speaker SP of the first speaker group. The low-frequency audio signal for four channels is input to the channel connection unit 124Bh.

The mid-high range audio signal that has passed through the second filtering unit 124Bc is amplified by the second gain unit 124Bd and input to the adding unit 124Bi. The second gain unit 124Bd is provided with an output end of 12 channels corresponding to each speaker SP of the first speaker group and the second speaker group. Therefore, audio signals in the mid-high range for 12 channels are input to the addition unit 124Bi.

The audio signal in the uncontrolled band that has passed through the uncontrolled band filtering unit 124Be is input to the selector unit 124Bf. The selector unit 124Bf sets the channel corresponding to each speaker SP. For example, in the present embodiment, in order to reproduce a sound field in which only the sound information Src1 can be heard substantially in the driver's seat, the selector unit 124Bf is provided from the speakers _{S_F Rr} and S_F _Rl installed in the listening area C_FR (driver's seat). The output is selected so that only the sound information Src1 is emitted.

The audio signal in the non-control band output from the selector unit 124Bf is input to the third gain unit 124Bg. The third gain unit 124Bg is provided with output ends of eight channels, and each output end is connected to each speaker SP of the second speaker group. The audio signal in the uncontrolled band for eight channels is input to the channel connecting unit 124Bh.

In the channel connection unit 124Bh, the input from the first gain unit 124Bb (low-frequency audio signal for 4 channels) and the input from the third gain unit 124Bg (audio signal in the non-control band for 8 channels) are connected. Will be done. The audio signals for the 12 connected channels are input to the addition unit 124Bi. That is, by the connection processing by the channel connection unit 124Bh, the audio signals for 12 channels are input to the addition unit 124Bi as in the input from the second gain unit 124Bd.

Even if the gain values of the first gain unit 124Bb, the second gain unit 124Bd, and the third gain unit 124Bg are predetermined values based on the results of tests and the like by a manufacturer or the like that provides the sound field reproduction system 1. Often, it may be a value appropriately set by the user. The gain values of the first gain unit 124Bb, the second gain unit 124Bd, and the third gain unit 124Bg may be the same value or different values. The coefficient calculation unit 122 may calculate the coefficients of these gain values.

The low-frequency 4-channel audio signal that has passed through the first filtering unit 124Ba is gained with the same gain value by the first gain unit 124Bb. As a result, in the low frequency part of each channel, there is no relative amplitude difference due to gain being applied at different gain values, so it is possible to adjust the volume without degrading the sound quality for the low frequency region. It becomes.

The 12-channel audio signal in the mid-high range that has passed through the second filtering unit 124Bc is gained with the same gain value by the second gain unit 124Bd. As a result, in the mid-high range of each channel, there is no relative amplitude difference due to gain being applied at different gain values, so it is possible to adjust the volume for the mid-high range without degrading the sound quality. It becomes.

The audio signal of each channel in the uncontrolled band that has passed through the uncontrolled band filtering unit 124Be is gained at the same gain value by the third gain unit 124Bg. This makes it possible to adjust the volume in the uncontrolled band portion of each channel.

That is, the first gain unit 124Bb is a first gain unit that gains the audio signal including a plurality of types of sound information (low frequency portion) corresponding to each speaker that has passed through the first filter with the same gain value. Works as. The second gain unit 124Bd operates as a second gain unit that gains the audio signal including a plurality of types of sound information (mid-high range portion) corresponding to each speaker that has passed through the second filter with the same gain value. do.

The audio signal of each channel to which the low frequency band, the mid-high frequency band, and the non-control band are added by the addition unit 124Bi is converted from the frequency domain to the time domain by the IFFT unit 124C and input to the EQ unit 124D.

In the EQ unit 124D, for example, PEQ (Parametric Equalizer) is used to suppress interference of audio signals between multipoint sound pressure control bands (between low frequencies and mid-high frequencies in this embodiment), or a multipoint sound pressure control band. Sound quality adjustment outside (uncontrolled band, 4000 Hz or higher in this embodiment) may be performed. In order to suppress interference, in the present embodiment, the same parameter values (center frequency, gain value, Q value, hereinafter referred to as "PEQ parameter value") are applied to all channels (speaker SP). .. By applying the same PEQ parameter value at least between the multi-point sound pressure control bands, the generation of relative amplitude difference and phase difference between the multi-point sound pressure control bands is avoided, and at least low to high frequencies are avoided. Interference of audio signals between multi-point sound pressure control bands is suppressed without causing deterioration of sound quality over the range.

That is, the EQ unit 124D has the same PEQ for an audio signal including a plurality of types of sound information (low frequency portion) that has passed through the first filter and a plurality of types of sound information (mid-high frequency region) that have passed through the second filter. It operates as an equalizer unit that performs equalizer processing using parameter values.

The PEQ parameter value may be a value predetermined by a manufacturer or the like that provides the sound field reproduction system 1 based on the result of a test or the like, or may be a value appropriately set by the user. The coefficient calculation unit 122 may calculate the coefficient of the PEQ parameter value.

The audio signal of each channel output from the EQ unit 124D is emitted as sound information from the speaker SP corresponding to each channel via the gain unit 126, the D / A converter 112, and the power amplifier 114.

In this way, by emitting the audio signal filtered by the multi-point sound pressure control unit 124B from each speaker SP, substantially only the sound information Src1 can be heard in the driver's seat and the passenger's seat, and the right side. In the rear seat and the left rear seat, a sound field in which only the sound information Src2 can be heard is reproduced. As an additional note, by setting more control points (second control points) for the mid-high range where phase shift is likely to occur than for the first control point for the low range, the sound pressure of the sound information Src1 and Src2 can be increased. Since it can be controlled with high accuracy, the above sound field can be reproduced with high accuracy.

9 (a) and 9 (b) show the impulse response reproduced at the first control point _{M_FR} in the listening area _{C_FR} (driver's seat) when the sound information Src1 and Src2 are emitted from each speaker SP. 9 (c) and FIG. 9 (d) show the amplitude characteristics (frequency response). FIG. 9 shows the impulse response and its amplitude characteristics for each channel (R channel and L channel of sound information Src1, R channel and L channel of sound information Src2).

In FIG. 9 (a), the vertical axis shows the normalized amplitude (Amplitude), and the horizontal axis shows the time (Time (unit: s)). In FIG. 9B, the vertical axis represents power (Power (unit: dB)) and the horizontal axis represents time (Time (unit: s)). In FIG. 9 (c), the vertical axis indicates power (Power (unit: dB)), and the horizontal axis indicates frequency (Frequency (unit: Hz)). In FIG. 9D, the vertical axis indicates the number of samples (Sample), and the horizontal axis indicates the frequency (Frequency (unit: Hz)). 10 (a) to 10 (d) show the same diagram as in FIGS. 9 (a) to 9 (d) for the second control point _{M_F Rl in} the listening area C_FR (driver's seat). 11 (a) to 11 (d) show the same diagram as in FIGS. 9 (a) to 9 (d) for the second control point _{M_FRr} in the listening area _{C_FR} (driver's seat).

The impulse response and its amplitude characteristics shown in FIGS. 9 to 11 take into consideration the gain values of the first gain unit 124Bb, the second gain unit 124Bd, and the third gain unit 124Bg, and the PEQ parameter values of the EQ unit 124D for convenience. It has become something that does not.

As can be seen from FIGS. 9 (b) and 9 (c), at the first control point _{M_FR} , the sound pressure in the low frequency portion of the sound information Src1 is mainly high. On the other hand, the sound pressure in the low frequency range of the sound information Src2 is significantly lower than the sound pressure in the low frequency range of the sound information Src1.

As can be seen from FIGS. 10 (b) and 10 (c) and FIGS. 11 (b) and 11 (c), at the second control point M_F _Rl and the second control point M_F _Rr , the sound information Src1 is mainly used. The sound pressure in the mid-high range is high. On the other hand, the sound pressure in the mid-high range portion of the sound information Src2 is significantly lower than the sound pressure in the mid-high range portion of the sound information Src1.

Therefore, in the listening area _{C_FR} (driver's seat), substantially only the sound information Src1 can be heard. The sound pressure of the second control point M_F _Rr is higher in the _R channel than in the L channel of the sound information Src1 in the listening area C_FR. At the second control point M_F _Rl , the sound pressure of the L channel is higher than that of the _R channel of the sound information Src1 in the listening area C_FR.

FIG. 12 shows the characteristics of the audio signals of the sound information Src1 and Src2. The audio signals of the sound information Src1 and Src2 are signals in which peaks appear every 2/3 octave. The audio signals of the sound information Src1 and Src2 are emitted from each speaker SP at the timing when the peaks of each appear alternately every 1/3 octave. In FIG. 12 (a), the vertical axis shows the normalized amplitude (Amplitude), and the horizontal axis shows the time (Time (unit: s)). In FIG. 12B, the vertical axis indicates power (Power (unit: dB)), and the horizontal axis indicates frequency (Frequency (unit: Hz)).

13 and 14 show the acoustic characteristics obtained in the listening area _{C_FR} (driver's seat) and the listening area _{C_RR} (right rear seat) when the sound information Src1 and Src2 are emitted, respectively. The acoustic characteristics shown in FIGS. 13 and 14 have power (Power (unit: dB)) on the vertical axis and frequency (Frequency (unit: Hz)) on the horizontal axis.

As can be seen from FIG. 13, in the listening area _{C_FR} (driver's seat), the sound information Src1 is from the sound information Src2 in the multipoint sound pressure control band (low to high range, 30 Hz or more and less than 4000 Hz in this embodiment). Is also larger than 20 dB. Therefore, in the listening area _{C_FR} , substantially only the sound information Src1 can be heard.

As can be seen from FIG. 14, in the listening area _{C_RR} (right rear seat), the sound information Src2 is 20 dB or more larger than the sound information Src1 in the multipoint sound pressure control band. Therefore, in the listening area _{C_RR} , substantially only the sound information Src2 can be heard.

Outside the multipoint sound pressure control band (non-control band), there is no sound pressure difference between the sound information Src1 and the sound information Src2 in any of the listening areas _{C_FR} and _{C_RR} . However, the power is weak in the uncontrolled band of 4000 Hz or higher. Therefore, the sound information Src2 of 4000 Hz or higher in the listening area _{C_FR} (driver's seat) does not substantially interfere with the listening of the sound information Src1 by the listener, and 4000 Hz or higher in the listening area _{C_RR} (right rear seat). The sound information Src1 does not substantially interfere with the listener's listening to the sound information Src2.

The above is the description of the exemplary embodiment of the present invention. The embodiments of the present invention are not limited to those described above, and various modifications can be made within the scope of the technical idea of the present invention. For example, the embodiment of the present application also includes the content that is appropriately combined with an example or the like exemplarily specified in the specification or a trivial example or the like.

In the above embodiment, the multipoint sound pressure control band is set to 30 Hz or more and less than 4000 Hz, but the multipoint sound pressure control band is not limited to this. For example, by increasing the number of speaker SPs installed and the number of control points set, the band in which the sound pressure can be controlled (that is, the multi-point sound pressure control band) can be expanded.

The configuration of the multi-point sound pressure control unit 124B shown in FIG. 8 may be appropriately changed. For example, in the above embodiment, the multi-point sound pressure control band is set to two in the low range and the mid-high range, but in another embodiment, even if three or more multi-point sound pressure control bands are set. good. As an example, the low range, the mid-high range, and the high range higher than the mid-high range may be set as the multi-point sound pressure control band. In this case, the multi-point sound pressure control unit 124B is provided with a filtering unit and a gain unit corresponding to each of the low range, the mid-high range, and the high range. The configurations of the channel connection unit 124Bh and the addition unit 124Bi are appropriately changed according to the number of installations of the filtering unit and the gain unit, the connection relationship between each gain unit and each speaker SP, and the like. Further, for example, in the EQ unit 124D, a PEQ parameter value corresponding to a high frequency range is added, and a speaker SP corresponding to the high frequency range is installed in the vehicle interior or a control point corresponding to the high frequency range is set.

In the above embodiment, the EQ unit 124D is installed after the IFFT unit 124C, but in another embodiment, for example, the gains of the first gain unit 124Bb, the second gain unit 124Bd, and the third gain unit 124Bg are obtained. An EQ unit (that is, a total of three EQ units) may be installed in the front stage or the rear stage of the unit. In this case, the equalizer processing using the same PEQ parameter value is applied to the audio signal of the low frequency channel 4 that has passed through the first filtering unit 124Ba, and the 12 channels of the mid-high frequency band that have passed through the second filtering unit 124Bc are subjected to equalizer processing. Equalizer processing using the same PEQ parameter value is applied to the audio signal, and equalizer processing using the same PEQ parameter value is applied to the audio signal of each channel in the uncontrolled band that has passed through the uncontrolled band filtering unit 124Be. Is given. In this embodiment, it is possible to perform equalizer processing using different PEQ parameter values for each of the low frequency region portion, the mid-high frequency region portion, and the non-restricted band portion of the audio signal.

In the above embodiment, the sound field reproduction system is configured to reproduce the sound field in the vehicle interior, but the present invention is not limited to this. In another embodiment, the sound field reproduction system may reproduce the sound field in another specific space such as in a house.

Further, in the above embodiment, a single device (sound field reproduction device 100) has a sound field measurement function and a sound field reproduction function, but the present invention is not limited to this. In another embodiment, the sound field reproduction system may be composed of a plurality of devices, and the sound field measurement function and the sound field reproduction function may be provided in separate devices constituting the system. As an example, a configuration is conceivable in which an information processing terminal such as a smartphone measures the sound field, and a device such as an in-vehicle device reproduces the sound field based on the measurement result.

1 Sound field reproduction system 100 Sound field reproduction device 102 Control unit 104 Display unit 106 Operation unit 108 Measurement signal generation unit 110 Channel selection unit 112 D / A converter 114 Power amplifier 116 Mike amplifier 118 A / D converter 120 Storage unit 122 Coefficient Calculation unit 124 Signal processing unit 124A FFT unit 124B Multi-point sound pressure control unit 124B 1st filtering unit 124Bb 1st gain unit 124Bc 2nd filtering unit 124Bd 2nd gain unit 124Be Non-control band filtering unit 124Bf Selector unit 124Bg 3rd gain unit 124Bh Channel connection unit 124Bi Addition unit 124C IFFT unit 124D EQ unit 126 Gain unit 200 Playback device

Claims (13)

The first filter and the second filter that limit multiple types of sound information to different frequency bands,
A plurality of first speakers that emit at least the former sound information to a plurality of areas among the plurality of types of sound information that has passed through the first filter and the plurality of types of sound information that has passed through the second filter.
A plurality of second speakers that emit the plurality of types of sound information that has passed through the second filter to the plurality of areas, and a plurality of second speakers.
A storage unit that stores a plurality of pairs of the transfer function of the first filter and the transfer function of the second filter as a pair.
When an input for designating a sound field to be reproduced is received, a set of transfer functions corresponding to the input is selected from the set of a plurality of transfer functions stored in the storage unit, and the first filter and the second transfer function are selected. The application part to apply to the filter and
Equipped with
The transfer function of the paired first filter and the transfer function of the second filter set at least one first control point for the first frequency band in each of the plurality of areas, and the first frequency band. A larger number of second control points targeting a higher second frequency band are set than the first control point, and one of the plurality of types of sound information is independently set in each of the plurality of areas. It is set to a value that controls the sound pressure of the plurality of types of sound information at each of the first control points and each of the second control points so that it can be heard.
When the set of transfer functions is applied to the first filter and the second filter by the application unit, the plurality of types of sound information emitted from the first speaker and the second speaker are used. A sound field that enables independent listening to one of the plurality of types of sound information in each of the areas, and reproduces the sound field specified by the input.
Sound field reproduction system. Among the plurality of first speakers and the plurality of second speakers, the number of speakers contributing to the setting of the second control point is larger than that of the speakers contributing to the setting of the first control point.
The sound field reproduction system according to claim 1. The speaker that contributes to the setting of the second control point is
Sound information including the second frequency band higher than the first frequency band is emitted.
The sound field reproduction system according to claim 2. The first filter is
The plurality of types of sound information are limited to the first frequency band, and the sound information is limited to the first frequency band.
The second filter is
Limiting the plurality of types of sound information to the second frequency band,
The sound field reproduction system according to any one of claims 1 to 3. Further provided is an equalizer unit for equalizing processing the plurality of types of sound information that has passed through the first filter and the plurality of types of sound information that has passed through the second filter using the same parameter values.
The sound field reproduction system according to any one of claims 1 to 4. A first gain unit that applies a gain with the same gain value to the plurality of types of sound information corresponding to each speaker that has passed through the first filter.
A second gain unit that applies a gain with the same gain value to the plurality of types of sound information corresponding to each speaker that has passed through the second filter.
Further prepare,
The sound field reproduction system according to any one of claims 1 to 5. The first filter and the second filter that limit the plurality of types of sound information to different frequency bands, the plurality of types of sound information that has passed through the first filter, and the plurality of types of sound information that have passed through the second filter. Among them, at least a plurality of first speakers that emit the former sound information to a plurality of areas, and a plurality of second speakers that emit the plurality of types of sound information that has passed through the second filter to the plurality of areas. A storage unit that stores a plurality of sets of the transmission function of the first filter and the transmission function of the second filter, and a plurality of storage units stored in the storage unit when an input for designating a sound field to be reproduced is received. A sound field is reproduced using a sound field reproduction system including a first filter and an application unit applied to the second filter by selecting a set of transmission functions corresponding to the input from the set of transmission functions of. It is a sound field reproduction method,
A step of applying the set of transfer functions to the first filter and the second filter by the application unit, and
A step of limiting the plurality of types of sound information to different frequency bands by the first filter and the second filter, and
At least the former sound information is emitted from the plurality of first speakers to the plurality of areas, and the plurality of types of sound information that has passed through the second filter is emitted from the plurality of second speakers to the plurality of areas. Steps and
Including
The transfer function of the paired first filter and the transfer function of the second filter set at least one first control point for the first frequency band in each of the plurality of areas, and the first frequency band. A larger number of second control points targeting a higher second frequency band are set than the first control point, and one of the plurality of types of sound information is independently set in each of the plurality of areas. It is set to a value that controls the sound pressure of the plurality of types of sound information at each of the first control points and each of the second control points so that it can be heard.
In the emitting step, one of the plurality of types of sound information is independently listened to in each of the plurality of areas by the sound information emitted from each of the first speaker and each of the second speakers. It is a sound field that enables this, and the sound field specified by the input is reproduced.
Sound field reproduction method. Among the plurality of first speakers and the plurality of second speakers, the number of speakers contributing to the setting of the second control point is larger than that of the speakers contributing to the setting of the first control point.
The sound field reproduction method according to claim 7. The speaker that contributes to the setting of the second control point is
Sound information including the second frequency band higher than the first frequency band is emitted.
The sound field reproduction method according to claim 8. The first filter is
The plurality of types of sound information are limited to the first frequency band, and the sound information is limited to the first frequency band.
The second filter is
Limiting the plurality of types of sound information to the second frequency band,
The sound field reproduction method according to any one of claims 7 to 9. Further including a step of equalizing the plurality of types of sound information that has passed through the first filter and the plurality of types of sound information that has passed through the second filter using the same parameter values.
The sound field reproduction method according to any one of claims 7 to 10. A step of applying a gain to the plurality of types of sound information corresponding to each speaker that has passed through the first filter using the same gain value.
A step of applying a gain to the plurality of types of sound information corresponding to each speaker that has passed through the second filter using the same gain value.
Including,
The sound field reproduction method according to any one of claims 7 to 11. A sound field reproduction program for causing a computer to execute the sound field reproduction method according to any one of claims 7 to 12.

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