JP2020010106A - Sound field reproduction system, sound field reproduction method, and sound field reproduction program - Google Patents

Abstract

To accurately control sound pressure of a plurality of types of sound information so that one of the plurality of types of sound information can be heard independently at each of a plurality of areas.SOLUTION: A sound field reproduction system comprises: a plurality of first speakers and a plurality of second speakers; and an application unit for applying a set of a transfer function for a first filter and a transfer function for a second filter forming a pair. The pair of the transfer function for the first filter and the transfer function for the second filter has a first control point and second control points set for each of a plurality of areas, the first control point targeting a first frequency band, the second control points targeting a second frequency band higher than the first frequency band, the number of the second control points is larger than the number of the first control point; and has values set for controlling sound pressure of a plurality of types of sound information at the first control point and the second control points so that one of the plurality of types of sound information can be heard independently at each of the plurality of areas.SELECTED DRAWING: Figure 8

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 Literature 1 describes a specific configuration of a sound field reproduction system of this type.

  The sound field reproduction system described in Patent Literature 1 controls the sound pressure of a low-frequency portion of sound information using a large-diameter indoor speaker installed in each door and the like, and controls a small sound installed in a headrest or the like of each seat. By controlling the sound pressure in the middle and high frequency portions of the sound information using a speaker near the aperture, a sound field with little deterioration in accuracy is reproduced in all seats in the vehicle cabin over the entire frequency band. .

JP 2007-19940 A

  In a vehicle cabin, for example, while a music piece is being reproduced by an audio device, voice guidance by a navigation device may be superimposed and reproduced. In this case, it is desirable that the driver sitting in the driver's seat can preferentially listen to the voice guidance by the navigation device, and the passenger sitting in the rear seat should preferentially listen to the music by the audio device.

  Therefore, using a sound field reproduction system, a plurality of types of sound information such as music and voice guidance can be independently listened to at each seat in the vehicle cabin. By controlling the sound pressure, for example, it is conceivable to reproduce a sound field in the vehicle cabin such that substantially only the voice guidance can be heard in the driver's seat and substantially only the music can be heard in the rear seat. . However, the sound field reproduction system described in Patent Literature 1 has a configuration specialized in accurately controlling the sound pressure of a single piece of sound information. Therefore, it is difficult for the sound field reproduction system described in Patent Document 1 to accurately control the sound pressures 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 one of a plurality of types of sound information to be independently listened to in each of a plurality of areas. An object of the present invention is to provide a sound field reproduction system, a sound field reproduction method, and a sound field reproduction program that can accurately control sound pressures of a plurality of types of sound information.

  A sound field reproduction system according to an 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, and a plurality of types of sound information that have passed through the first filter. Among a plurality of types of sound information that have passed through the filter, a plurality of first speakers that emit at least the former sound information to a plurality of areas, and a plurality of types that emit the plurality of types of sound information that have passed the second filter to a plurality of areas , A storage unit that stores a plurality of pairs of a transfer function of the first filter and a transfer function of the second filter, and a storage unit that receives an input designating a sound field to be reproduced. An application unit that selects a set of transfer functions according to the input from the stored plurality of sets of transfer functions and applies the set to the first filter and the second filter. The transfer function of the first filter and the transfer function of the second filter, which form a pair, 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. More second control points for the second frequency band are 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. Is set to a value for controlling the sound pressure of a plurality of types of sound information at each of the first control point and each of the second control points. When the set of transfer functions is applied to the first filter and the second filter by the application unit, the sound field reproduction system uses a plurality of types of sound information emitted from each of the first speaker and each of the second speakers to generate a plurality of areas. Are sound fields that allow one of a plurality of types of sound information to be independently listened to, and reproduce the sound field specified by the input.

  Among 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 the number of speakers that contribute to the setting of the first control point.

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

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

  The sound field reproduction system may be configured to further include an equalizer unit that performs equalizer processing on the plurality of types of sound information passed through the first filter and the plurality of types of sound information passed through the second filter using the same parameter value. Good.

  The sound field reproduction system includes a first gain unit that applies a gain to the plurality of types of sound information corresponding to each speaker that has passed through the first filter with the same gain value, and a speaker that has passed through the second filter. A configuration may further include a second gain unit that applies a gain to the corresponding plurality of types of sound information with the same gain value.

  A sound field reproduction method according to an 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, and a plurality of types of sound information that have passed through the first filter. Among a plurality of types of sound information that have passed through the filter, a plurality of first speakers that emit at least the former sound information to a plurality of areas, and a plurality of types that emit the plurality of types of sound information that have passed the second filter to a plurality of areas , A storage unit that stores a plurality of pairs of a transfer function of the first filter and a transfer function of the second filter, and a storage unit that receives an input designating a sound field to be reproduced. Reproducing a sound field using a sound field reproduction system including a transfer function set according to an input selected from a plurality of stored transfer function sets and applied to a first filter and a second filter. Is a way to Applying a set of transfer functions to the first filter and the second filter by the application unit; limiting the plurality of types of sound information to different frequency bands by the first filter and the second filter; From a plurality of first speakers to a plurality of areas, and releasing a plurality of types of sound information passing through the second filter from the plurality of second speakers to a plurality of areas. The transfer function of the first filter and the transfer function of the second filter, which form a pair, 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. More second control points for the second frequency band are 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. Is set to a value for controlling the sound pressure of a plurality of types of sound information at each of the first control point and each of the second control points. In the emitting step, one of the plurality of types of sound information can be 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. A sound field that reproduces the sound field specified by the input.

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

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

It is a block diagram showing the composition of the sound field reproduction system concerning one embodiment of the present invention. FIG. 2A is a diagram showing a plurality of listening areas arranged in a vehicle cabin according to an embodiment of the present invention, and FIG. 2B shows an installation position of each speaker in the vehicle cabin and a position of each control point set in the vehicle cabin. It is a figure (FIG.2 (b)). It is a figure showing the flow chart of the sound field measurement processing performed in the sound field reproduction system concerning one embodiment of the present invention. FIG. 4A shows an impulse response (linear scale) of each speaker picked up by a microphone installed at a first control point in a listening area (driver's seat) in an embodiment of the present invention; FIG. 4B shows the impulse response (decibel scale) of each speaker picked up by the microphone installed at the first control point in the listening area (driver's seat) (FIG. 4B) and in the listening area (driver's seat). FIG. 4C is a diagram illustrating an amplitude characteristic of an impulse response of each speaker picked up by a microphone installed at a first control point (FIG. 4C). In one embodiment of the present invention, a diagram showing an impulse response (linear scale) of each speaker picked up by a microphone installed at one of a pair of second control points in a listening area (driver's seat) (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 a listening area (driver's seat) (FIG. 5 (b)) and FIG. 5C is a diagram illustrating an amplitude characteristic of an impulse response of each speaker picked up by a microphone installed at one of a pair of second control points in a listening area (driver's seat). In one embodiment of the present invention, a diagram showing an impulse response (linear scale) of each speaker picked up by a microphone installed at the other of the pair of second control points in the listening area (driver's seat) (FIG. a)), a diagram showing an impulse response (decibel scale) for each speaker picked up by a microphone installed at the other of the pair of second control points in the listening area (driver's seat) (FIG. 6 (b)) and FIG. 6C is a diagram illustrating an amplitude characteristic of an impulse response of each speaker picked up by a microphone installed at the other of the pair of second control points in the listening area (driver's seat) (FIG. 6C). It is a block diagram showing composition of a signal processor of a sound field reproduction device with which a sound field reproduction system concerning one embodiment of the present invention is provided. FIG. 3 is a block diagram illustrating a configuration of a multipoint sound pressure control unit provided in a signal processing unit according to an embodiment of the present invention. FIG. 9A is 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 cabin according to an embodiment of the present invention. 9 (b)) and a diagram showing the amplitude characteristics thereof (FIGS. 9 (c) and 9 (d)). In one embodiment of the present invention, a diagram showing an impulse response reproduced at one of a pair of second control points in a listening area (driver's seat) when two types of sound information are emitted from a speaker in a vehicle compartment (FIG. 10 (a) and 10 (b)) and a diagram (FIG. 10 (c) and FIG. 10 (d)) showing the amplitude characteristics thereof. FIG. 4 is a diagram showing an impulse response reproduced at the other of the pair of second control points in the listening area (driver's seat) when two types of sound information are emitted from the speaker in the vehicle compartment in one embodiment of the present invention (FIG. 11 (a) and 11 (b)) and diagrams (FIGS. 11 (c) and 11 (d)) showing their amplitude characteristics. FIG. 3 is a diagram illustrating characteristics of audio signals of two types of sound information emitted from a speaker in a vehicle cabin according to an embodiment of the present invention. FIG. 4 is a diagram illustrating acoustic characteristics obtained in a listening area (driver's seat) when two types of sound information are emitted from a speaker in a vehicle cabin according to an embodiment of the present invention. It is a figure which shows the acoustic characteristic obtained in a listening area (right rear seat) when two types of sound information are emitted from the speaker in a vehicle interior in one embodiment of the present 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 compartment will be described as an example.

  FIG. 1 is a block diagram illustrating a configuration of a sound field reproduction system 1 according to an embodiment of the present invention. The sound field reproduction system 1 according to the present embodiment is configured such that sound pressures of a plurality of types of sound information emitted from a plurality of speakers installed in the vehicle cabin have a desired value at each control point in the vehicle cabin. This is a system that controls the sound pressure of an audio signal (signal for reproducing 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. Note that, in FIG. 1, connections between the control unit 102 and other components are omitted as appropriate in order to avoid complicating the drawing.

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

  The sound field reproduced by the sound field reproduction system 1 enables one of a plurality of types of sound information to be independently listened to in each of a plurality of listening areas arranged in a closed space of a vehicle interior. It is a sound field. In the present embodiment, the plurality of listening areas are each seat 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 the voice guidance can be heard substantially in the driver's seat and substantially only the music can be heard in the rear seat.

  Note that various processes in the sound field reproduction system 1 are executed by cooperation of software and hardware provided in the sound field reproduction system 1. At least an OS (Operating System) part of 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 that are pre-installed in the sound field reproduction system 1 or functions that can be added via a network or a recording medium. .

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

FIG. 2A shows a plurality of listening areas (areas surrounded by broken lines, in other words, seats) arranged in the vehicle interior. Driver's seat, the front passenger seat, rear right seat, to each listening area of the left rear seat, the code "C_F _R" each, "C_F _L", "C_R _R", given the "C_R _L".

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 at the driver's seat right side door is denoted by the symbol "S_F _R ", the speaker SP installed at the passenger seat left door portion is denoted by the symbol "S_F _L ", and the right rear denoted by the symbol "S_R _R" to the right speaker SP, which is installed in the door portion of the seat, reference numeral "S_R _L" to the speaker SP, which is installed in the door portion of the left side of the left rear seat.

Thus, the speakers _{S_F R, S_F L, S_R R} , S_R L is a plurality of types of sound in each of the plurality of the listening area in the door is installed in a unit, the sound field reproduction system 1 that is outside the listening area When reproducing a sound field that allows one of the information to be heard independently, low and mid-high frequencies are emitted. In this embodiment, a speaker _{S_F R, S_F L, S_R R} , has established a S_R _L outside the listening area, in another embodiment, a speaker _{S_F R, S_F L, S_R R} , listening area the S_R _L It may be installed in.

Speaker S_F _R, S_F _L, S_R R and S_R _L among the plurality of types of sound information passing through a plurality of types of sound information which has passed through the first filter and the second filter, at least the former of the sound information into a plurality of areas This is a specific example of a plurality of first speakers that emit (described later in detail). Hereinafter referred to as "first speaker group" collectively these speakers S_F _R, S_F _L, S_R _R and S_R _L.

The speaker SP installed at the right side of the driver's seat headrest is denoted by “S_F _Rr ”, and the speaker SP installed at the left side of the driver's headrest is denoted by “S_F _Rl ”. The speaker SP installed at the position on the right side of the headrest is denoted by “S_F _Lr ”, the speaker SP installed on the left side of the headrest at the passenger seat is denoted by “S_F _Ll ”, and the The speaker SP installed at the position on the right of the headrest is denoted by “S_R _Rr ”, the speaker SP installed on the left of the headrest of the right rear seat is denoted by “S_R _Rl ”, and the speaker SP is mounted on the left rear seat. reference numeral "S_R _Lr" the speaker SP installed in the right side position of the head restraint, which is installed to the left of the position of the headrest of the left rear seat scan Denoted by the symbol "S_R _Ll" in over mosquito SP.

Thus, 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 in the headrest outside each listening area, and 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 listened to in each of the plurality of listening areas, a mid-high range is emitted. In this 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.

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 emit a plurality of types of sound information passing through the second filter to a plurality of areas (details will be described later). 2 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 a “second speaker group”.

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

Hereinafter, the driver's seat, passenger seat, rear right seat, the control points set in the respective central positions of the left rear seat, reference numeral "M_F _R" respectively, "M_F _L", "M_R _R", denoted by "M_R _L" . These control points _{M_F R, M_F L, M_R R} , the M_R _L are collectively referred to as "first control point". The first control point is a control point for a low frequency band. At the first control point, when a plurality of types of sound information is emitted from each speaker SP, a desired sound pressure is obtained for a low-frequency portion of the plurality of types of sound information.

  In the present embodiment, low-frequency portions of a plurality of types of sound information are 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 of each listening area.

Also, control points set at positions near the right and left ears of the listener sitting in the driver's seat are denoted by “M_F _Rr ” and “M_F _Rl ”, respectively, and the right and left of the listener sitting in the front passenger's seat are assigned. The control points set at the positions near the ears are denoted by “M_F _Lr ” and “M_F _Ll ”, respectively, and the control set at the positions near the right and left ears of the listener sitting on the right rear seat is shown. The symbols “M_R _Rr ” and “M_R _Rl ” are assigned to the points, respectively, and the symbols “M_R _Lr ” and “M_R” are assigned to the control points set at positions near the right and left ears of the listener sitting on the left rear seat, respectively. _Ll ". 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 a “second control point”. The second control points are control points for the middle and high ranges, and have a larger number than the first control points. At the second control point, when a plurality of types of sound information is emitted from each speaker SP, a desired sound pressure is obtained for the middle and high frequency portions of the plurality of types of sound information.

  In the present embodiment, the middle and high frequency portions of a plurality of types of sound information are 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 of each listening area.

  As described above, the number of the speakers SP that emits the middle and high frequency portions of the plurality of types of sound information is larger than the number of the speakers SP that emits the low range portions of the plurality of types of sound information, and contributes to the setting of the second control point. The number of loudspeakers SP to be set is larger than the number of loudspeakers SP that contribute to the setting of the first control point.

  In this embodiment, only the first loudspeaker group emits low-frequency portions of a plurality of types of sound information, and both the first loudspeaker group and the second loudspeaker group emit mid-high-frequency portions 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 middle-high-frequency portion of a plurality of types of sound information. Also in this case, the number of the speakers SP that emits the middle and high frequency portions of the plurality of types of sound information is larger than the number of the speakers SP that emits the low range portions of the plurality of types of sound information, and also contributes to the setting of the second control point. The number of loudspeakers SP to be set is larger than the number of loudspeakers SP that contribute to the setting of the first control point.

  If a desired sound pressure is obtained at the first control point and the second control point, a desired sound field is reproduced at least in the entire area of each listening area. The control points (in other words, a microphone MIC described later) may be arranged in a layout surrounding 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 a desired sound field in the vehicle interior (in other words, to obtain a desired sound pressure at each control point in the vehicle interior), it is necessary to perform sound field measurement first. When performing a sound field measurement, a microphone MIC is 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 microphones MIC is installed at a predetermined position (second control point) of the headrest of each seat. Since there are four seats, a total of 12 microphones MIC are installed in the vehicle interior.

  The higher the frequency, the greater the phase shift of the sound information heard by the listener when, for example, the listener's head deviates from a position assumed in design. Therefore, in the present embodiment, the accuracy of the sound pressure at the second control point for the middle and high ranges is improved (priority over the accuracy of the sound pressure at the first control point for 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 one 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 receiving a predetermined touch operation on the display unit 104 or a predetermined operation on the operation unit 106, the control unit 102 displays an input screen for sound field measurement conditions on the display unit 104. Thus, the sound field measurement processing shown in the flowchart is started.

  When the user inputs sound field measurement conditions on the input screen displayed on the display unit 102, the input sound field measurement conditions are set (step S11). The sound field measurement condition input here is, for example, the number of channels (or designation of a speaker to be measured). Since the sound field reproduction system 1 according to the present embodiment includes 12 speakers, the maximum number of inputtable channels is “12”. In the present embodiment, description will be made assuming that the number of channels of 12 has been input.

  In order to avoid inconvenience that unnecessary sound information is output 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, a 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 generator 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 a channel selection unit 110, a D / A converter 112, and a power amplifier 114. It is emitted from the SP as sound for sound field measurement.

  The sound field measurement sound emitted from the speaker SP to be measured is collected by all the microphones MIC in the vehicle compartment, and is 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). The impulse response is obtained by, for example, performing a Fourier transform on a reference signal having an inverse characteristic obtained by inverting an input sound field measurement sound and a reference measurement signal (such as a TSP signal) on a time axis, and multiplying the resulting signal on a frequency. It is obtained by performing an inverse Fourier transform on the obtained value.

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

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

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

Figure 4 (a), 4 (b), the listening area C_F the _R (driver's seat) first control point intended for the picked-up speaker (low frequency in the microphones MIC installed in the control point M_F _R of showing first speaker) each impulse response corresponding to the control point M_F _R is (linear scale), the impulse response (decibel scale), respectively. Figure 4 (c), shows the amplitude characteristic of the impulse response of each speaker picked up by the installed microphone MIC to the control point M_F _R (frequency response). The frequency response is obtained, for example, by performing an Fourier transform on the impulse response by an FFT (Fast Fourier transform) unit 124A (described later) of the signal processing unit 124.

In FIG. 4A, the vertical axis indicates the normalized amplitude (Amplitude), and the horizontal axis indicates 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. 4C, the vertical axis represents power (Power (unit: dB)), and the horizontal axis represents frequency (Frequency (unit: Hz)). Power is the square of the amplitude. In addition, human auditory characteristics are logarithmic with respect to frequency. The horizontal axis in FIG. 4C is logarithmic in accordance with human auditory characteristics. 5 (a) to 5 (c) show diagrams similar to FIGS. 4 (a) to 4 (c) for the control point M_F _Rl . 6 (a) to 6 (c) show diagrams similar to FIGS. 4 (a) to 4 (c) for the control point M_F _Rr . In addition, in FIGS. 5A to 5C and FIGS. 6A to 6C, the control point M_F _Rl and the control point M_F, which are the second control points for the middle and high ranges, are shown. ₇ shows an impulse response corresponding to _Rr for each of the first and second speakers and an amplitude characteristic thereof.

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

  Each audio signal of a plurality of types of sound information input from the playback device 200 is converted from the time domain to the frequency domain by the FFT unit 124A, and is output to the multipoint sound pressure control unit 124B. The audio signal in the frequency domain input to the multi-point sound pressure control unit 124B is subjected to filtering that allows one of a plurality of types of sound information to be independently heard in each listening area. The audio signal filtered by the multipoint 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 section 124D is equalized and output to the gain section 126.

  Since filtering is performed by multiplication in the frequency domain in the multipoint sound pressure control unit 124B, the FFT performed by the FFT unit 124A and the IFFT performed by the IFFT unit 124C at the subsequent stage have arithmetic contents in consideration of linear convolution.

  FIG. 8 is a block diagram illustrating a configuration of the multipoint sound pressure control unit 124B. As shown in FIG. 8, the multipoint 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, a non-control band filtering unit 124Be, and a selector unit. 124Bf, a third gain unit 124Bg, a channel connecting unit 124Bh, and an adding 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 non-control band filtering unit 124Be. The first filtering unit 124Ba passes a low-frequency portion of the audio signal, the second filtering unit 124Bc passes a middle-high frequency portion of the audio signal, and the non-control band filtering unit 124Be outputs a non-control band of the audio signal. (A band other than the pass band of the first filtering unit 124Ba and a band other than the pass band of the second filtering unit 124Bc).

  The filter transfer functions of the first filtering unit 124Ba and the second filtering unit 124Bc are calculated by the coefficient calculating unit 122.

The audio signal of the sound information to be reproduced in the reproduction you want to sound field at each control point M _i of the passenger compartment marked "X _{i (ω)",} each control point of the passenger compartment in the actual playback sound field M _{k (k} = 1 to M), the audio signal of the sound information reproduced is referred to as “Y _k (ω)”. When the system introduces a linear phase delay ∠φ (ω) that satisfies causality, the relationship between the audio signal X _i (ω) to be reproduced and the audio signal Y _k (ω) to be reproduced is expressed 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 different from the sound information originally intended to be reproduced. 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 the present embodiment, the latter uniform delay is expressed as "linear phase delay in which the system satisfies causality".

(Equation 1)

It is assumed that the audio signal X _i (ω) is processed by MN filters G _ij (ω) in the reproduction sound field, and between the speaker SP _j (j = 1 to N) and the control point M _k (k = 1 to M). Is defined as 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 delay ∠φ (ω), and the space transfer function H _jk (ω) are all known. Specifically, the audio signal X _i (ω) is a target value at the control point (a signal to be reproduced at the control point). The phase delay Δφ (ω) is, for example, a value determined in advance by a manufacturer such as a manufacturer that provides the sound field reproduction system 1 based on a result of a test or the like. The space transfer function H _jk (ω) is an amplitude characteristic of an impulse response illustrated in FIG. The amplitude characteristics of the spatial transfer function H _{jk (omega)} and the impulse response are different in a strict sense, because there is no harm even substantially equate the present embodiment, the amplitude characteristic spatial transfer function H _jk impulse response ( ω).

Since the audio signal X _i (ω), the phase delay ∠φ (ω), and the space transfer function H _jk (ω) are known, the coefficient calculation unit 122 determines the filter G _ij ( ω) can be calculated. The filter G _ij (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 playback device 200 to the sound field reproduction device 100. Hereinafter, each of the two types of sound information is 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 substantially heard in the driver's seat and the passenger's seat, and substantially only the sound information Src2 can be heard in the right rear seat and the left rear seat is reproduced. I do. In this case, the first control point M_F _R directed to the low frequency, M_F _L, M_R _R, when applying the above equation 2 for M_R _L, 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 at which seat (that is, a sound field to be reproduced).

(Equation 3)
However,

The storage unit 120 stores, for example, a filter G _ij (ω) calculated using Expression 3 above. For convenience, the filter _{G ij} illustrated by Formula 3 (omega), i.e., the first control point M_F _R directed to the low frequency, M_F _L, M_R _R, filter G obtained by calculating the M_R _{L ij} (ω) is referred to as “low-pass filter G _ij (ω)”.

The storage unit 120 also stores a middle-high band filter G _ij (ω) paired with the low band filter G _ij (ω). The “middle-high range filter G _ij (ω)” calculates 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 middle and high range. The obtained filter G _ij (ω). In the present embodiment, the pair of low-pass filter Gij (ω) and the middle-high-pass filter Gij (ω) are applied to the first filtering unit 124Ba and the second filtering unit 124Bc, respectively. In the passenger seat, it is possible to reproduce a sound field in which only the sound information Src1 can be substantially heard, and in the right rear seat and the left rear seat, substantially only the sound information Src2 can be heard.

  The storage unit 120 stores, for each sound field to be reproduced (for example, a sound in which only the sound information Src1 can be substantially heard in the driver's seat and the front passenger seat and a sound in which only the sound information Src2 can be substantially heard in the right rear seat and the left rear seat). Low-pass filter paired with a sound field in which only the sound information Src2 can be heard substantially at the driver's seat, the driver's seat, and the passenger seat, and substantially only the sound information Src1 can be heard at the right rear seat and the left rear seat. A set of Gij (ω) and a middle-high band filter Gij (ω) is stored. Under the control of the control unit 102, a set of a low-pass filter Gij (ω) and a middle-high-pass filter Gij (ω) corresponding to the sound field specified by the operation unit 106 is selected from the plurality of sets. The low-pass filter Gij (ω) and the middle-high-pass filter Gij (ω) thus obtained are applied to the first filtering unit 124Ba and the second filtering unit 124Bc, respectively.

  The first filtering unit 124Ba allows, for example, an audio signal of 30 Hz or more and less than 200 Hz to pass. As an example, the second filtering unit 124Bc allows an audio signal of 200 Hz or more and less than 4000 Hz to pass. The non-control band filtering unit 124Be allows an audio signal of 4000 Hz or more to pass, for example. As described above, since the first filtering unit 124Ba and the second filtering unit 124Bc consider a linear phase delay that satisfies the causality of the system, the audio signal passing through the non-control band filtering unit 124Be is The same delay as the audio signal passing through the first filtering unit 124Ba and the second filtering unit 124Bc is provided.

  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 section 124Bb is provided with four-channel output terminals corresponding to the speakers SP of the first speaker group. The low-frequency audio signals for four channels are input to the channel coupling unit 124Bh.

  The audio signal in the middle and high frequencies 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 section 124Bd is provided with an output terminal of 12 channels corresponding to each speaker SP of the first speaker group and the second speaker group. Therefore, audio signals in the middle and high frequencies for 12 channels are input to the adder 124Bi.

The audio signal in the non-control band that has passed through the non-control band filtering unit 124Be is input to the selector unit 124Bf. The selector unit 124Bf performs channel setting corresponding to each speaker SP. For example, in this embodiment, in order to reproduce the sound field that can listen to substantially only the sound information Src1 in the driver's seat, the selector unit 124Bf a speaker S_F _Rr installed in the listening area C_F the _R (driver's seat), from S_F _Rl The output is selected so that only the sound information Src1 is emitted.

  The audio signal of 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 eight channel output terminals, and each output terminal is connected to each speaker SP of the second speaker group. The audio signal of the non-control band for eight channels is input to the channel coupling unit 124Bh.

  In the channel connecting unit 124Bh, the input from the first gain unit 124Bb (low-frequency audio signal for four channels) and the input from the third gain unit 124Bg (non-control band audio signal for eight channels) are connected. Is done. The concatenated audio signals for 12 channels are input to the adder 124Bi. That is, by the connection processing by the channel connection unit 124Bh, audio signals for 12 channels are input to the addition unit 124Bi, similarly to the input from the second gain unit 124Bd.

  The gain values of the first gain unit 124Bb, the second gain unit 124Bd, and the third gain unit 124Bg may be values determined in advance by a manufacturer or the like that provides the sound field reproduction system 1 based on results of tests and the like. Alternatively, it may be a value appropriately set by the user. The gain values of the first gain section 124Bb, the second gain section 124Bd, and the third gain section 124Bg may be the same value or different values. The coefficient calculator 122 may calculate the coefficients of these gain values.

  The first gain unit 124Bb applies a gain to the low-frequency four-channel audio signal that has passed through the first filtering unit 124Ba with the same gain value. As a result, there is no relative amplitude difference due to gain being applied at different gain values in the low-frequency portion of each channel, so that the volume can be adjusted without deteriorating the sound quality of the low-frequency portion. Becomes

  The second gain section 124Bd applies a gain to the 12-channel audio signal of the middle and high frequency range that has passed through the second filtering section 124Bc with the same gain value. As a result, since a relative amplitude difference does not occur in the middle and high frequency portions of each channel due to gain being applied with different gain values, it is possible to adjust the volume of the middle and high frequency portions without deteriorating sound quality. Becomes

  The third gain unit 124Bg applies a gain to the audio signal of each channel of the non-control band that has passed through the non-control band filtering unit 124Be with the same gain value. This makes it possible to adjust the volume in the non-control band portion of each channel.

  That is, the first gain unit 124Bb applies a gain to the audio signal that has passed through the first filter and includes a plurality of types of sound information (low-frequency parts) corresponding to the respective speakers with the same gain value. Works as The second gain section 124Bd operates as a second gain section that applies a gain with the same gain value to an audio signal that has passed through the second filter and includes a plurality of types of sound information (middle and high frequency portions) corresponding to each speaker. I do.

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

  The EQ unit 124D uses, for example, a PEQ (Parametric Equalizer) to suppress the interference of the audio signal between the multi-point sound pressure control bands (in the present embodiment, between the low band and the middle and high band), or to control the multi-point sound pressure control band. Sound quality adjustment outside (non-control band, 4000 Hz or more in the present embodiment) is performed. In this embodiment, the same parameter values (the center frequency, the gain value, and the Q value; hereinafter, referred to as “PEQ parameter values”) are applied to all the channels (speakers SP) for interference suppression. . By applying the same PEQ parameter value at least between the multi-point sound pressure control bands, it is possible to avoid occurrence of a relative amplitude difference or phase difference between the multi-point sound pressure control bands, and at least from a low band to a high band. The interference of the audio signal between the multi-point sound pressure control bands is suppressed without causing the deterioration of the sound quality over the range.

  In other words, the EQ unit 124D applies the same PEQ to an audio signal containing a plurality of types of sound information (low-frequency part) passed through the first filter and a plurality of types of sound information (middle-high frequency part) 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 determined in advance by a manufacturer or the like that provides the sound field reproduction system 1 based on the results of a test or the like, or may be a value appropriately set by a user. The coefficient calculator 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.

  As described above, the audio signal that has been subjected to the filtering processing in the multipoint sound pressure control unit 124B is emitted from each speaker SP, so that substantially only the sound information Src1 can be heard in the driver's seat and the passenger seat, and In the rear seat and the left rear seat, a sound field in which substantially only the sound information Src2 can be heard is reproduced. In addition, the sound pressures of the sound information Src1 and Src2 are set by setting the number of control points (second control points) for the middle and high ranges in which a phase shift is likely to occur more than the first control points for low frequencies. Since the control can be performed with high accuracy, it is possible to accurately reproduce the above sound field.

FIG. 9 (a) and FIG. 9 (b), the impulse response sound information Src1 and Src2 from the speakers SP is reproduced by the first control point M_F _R of the listening area C_F in _R when released (driver's seat) FIG. 9C and FIG. 9D show the amplitude characteristics (frequency response). FIG. 9 shows an impulse response for each channel (R channel and L channel of sound information Src1 and R channel and L channel of sound information Src2) and their amplitude characteristics.

In FIG. 9A, the vertical axis indicates the normalized amplitude (Amplitude), and the horizontal axis indicates 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. 9C, 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)). Figure 10 (a) ~ FIG 10 (d), shows a similar view to the listening area C_F in _R for the second control point M_F _Rl of (driver's seat) Fig. 9 (a) ~ FIG 9 (d). Figure 11 (a) ~ FIG 11 (d), shows a similar view to the second control point M_F _Rr in the listening area C_F _R (driver's seat) Fig. 9 (a) ~ FIG 9 (d).

  Note that the impulse responses and their amplitude characteristics shown in FIGS. 9 to 11 take into account the gain values of the first gain section 124Bb, the second gain section 124Bd, and the third gain section 124Bg and the PEQ parameter value of the EQ section 124D for convenience. It is not done.

Figure 9 (b) and as seen from FIG. 9 (c), the the first control point M_F _R, mainly, the sound pressure of the low-frequency part of the sound information Src1 is high. On the other hand, the sound pressure of the low frequency part of the sound information Src2 is significantly lower than the sound pressure of the low frequency part of the sound information Src1.

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

Therefore, in the listening area C_F the _R (driver's seat), it is possible to listen to only the substantially sound information Src 1. Note that the second control point M_F _Rr, at the listening area C_F the _R, towards the R channel than L-channel sound information Src1 sound pressure is higher. The second control point M_F _Rl, at the listening area C_F the _R, towards the L channel than R-channel sound information Src1 sound pressure is higher.

  FIG. 12 shows characteristics of audio signals of the sound information Src1 and Src2. Each of the audio signals of the sound information Src1 and Src2 is a signal whose peak appears every ／ octave. The audio signals of the sound information Src1 and Src2 are emitted from the respective speakers SP at timings at which respective peaks alternately appear every 1/3 octave. In FIG. 12A, the vertical axis indicates the normalized amplitude (Amplitude), and the horizontal axis indicates time (Time (unit: s)). In FIG. 12B, the vertical axis represents power (Power (unit: dB)), and the horizontal axis represents frequency (Frequency (unit: Hz)).

13 and 14, respectively, showing an acoustic characteristic obtained by listening area C_F _R (driver's seat), the listening area C_R _R (right rear seat) when the sound information Src1 and Src2 was released. 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_F _R (driver's seat), the sound information Src1 is different from the sound information Src2 in the multipoint sound pressure control band (from low to high, in this embodiment, 30 Hz or more and less than 4000 Hz). Is also larger than 20 dB. Therefore, in the listening area C_F _R, substantially only the sound information Src1 has become audible.

As can be seen from Figure 14, the listening area C_R _R (right rear seat), greater than 20dB than sound information Src2 Gaoto information Src1 in multi Ten'on pressure control band. Therefore, in the listening area C_R _R, substantially only the sound information Src2 has become audible.

In multi Ten'on pressure control band (non-control band), the listening area C_F _R, there is no sound pressure difference between the sound information Src1 and sound information in any of C_R _R Src 2. However, the power is weak in the non-control band of 4000 Hz or more. Therefore, the listening area C_F _R (driver's seat) 4000Hz or more sound information Src2 in that never substantially interfere with the listening of the sound information Src1 by the listener, also more than 4000Hz in the listening area C_R _R (right rear seat) The sound information Src1 does not substantially prevent the listener from 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 are possible within the scope of the technical idea of the present invention. For example, the embodiments of the present application also include examples and the like exemplarily shown in the specification or contents obtained by appropriately combining obvious examples and the like.

  In the above embodiment, the multipoint sound pressure control band is set to be 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 speakers SP and the number of control points to be set, the band in which the sound pressure can be controlled (that is, the multipoint sound pressure control band) can be expanded.

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

  In the above embodiment, the EQ unit 124D is provided at a stage subsequent to the IFFT unit 124C, but in another embodiment, for example, each gain of the first gain unit 124Bb, the second gain unit 124Bd, and the third gain unit 124Bg An EQ section (that is, three EQ sections in total) may be provided before or after the section. In this case, equalization processing using the same PEQ parameter value is performed on the low-frequency four-channel audio signals that have passed through the first filtering unit 124Ba, and the middle and high-frequency 12-channel audio signals that have passed through the second filtering unit 124Bc. An equalizer process using the same PEQ parameter value is performed on the audio signal, and an equalizer process using the same PEQ parameter value on the audio signal of each channel in the non-control band that has passed through the non-control band filtering unit 124Be Is applied. In this embodiment, it is possible to perform an equalizer process using different PEQ parameter values on each of the low-band portion, the middle-high band portion, and the unrestricted 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 a sound field in another specific space, such as in a house.

  Further, in the above embodiment, the single device (sound field reproducing device 100) has the sound field measuring function and the sound field reproducing 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 different devices constituting the system. As an example, a configuration is conceivable in which an information processing terminal such as a smartphone performs a sound field measurement, 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 apparatus 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 microphone amplifier 118 A / D converter 120 storage unit 122 coefficient Operation unit 124 Signal processing unit 124A FFT unit 124B Multipoint sound pressure control unit 124Ba First filtering unit 124Bb First gain unit 124Bc Second filtering unit 124Bd Second gain unit 124Be Non-control band filtering unit 124Bf Selector unit 124Bg Third gain unit 124Bh Channel connection unit 124Bi Addition unit 124C IFFT unit 124D EQ unit 126 Gain unit 200 Playback device

Claims (13)

A first filter and a second filter for limiting a plurality of types of sound information to different frequency bands, respectively;
A plurality of first speakers that emit at least the former sound information to a plurality of areas, among the plurality of kinds of sound information passing through the first filter and the plurality of kinds of sound information passing through the second filter;
A plurality of second speakers that emit the plurality of types of sound information that have passed through the second filter to the plurality of areas;
A storage unit that stores a plurality of pairs of a transfer function of the first filter and a transfer function of the second filter as a pair;
When receiving an input designating a sound field to be reproduced, a set of transfer functions corresponding to the input is selected from a plurality of sets of transfer functions stored in the storage unit, and the first filter and the second filter are selected. An application unit applied to the filter,
With
The transfer function of the first filter and the transfer function of the second filter are at least one first control point for the first frequency band in each of the plurality of areas, and the first frequency band A plurality of second control points targeting a higher second frequency band than the first control point are set, 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 the user can listen to the sound.
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 each of the first speaker and each of the second speakers allow the plurality of sets of sound information to be transmitted. A sound field that allows one of the plurality of types of sound information to be independently listened to 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 that contribute to the setting of the second control point is larger than the number of speakers that contribute 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 includes:
Emitting sound information including at least the second frequency band higher than the first frequency band;
The sound field reproduction system according to claim 2. The first filter includes:
Limiting the plurality of types of sound information to the first frequency band,
The second filter includes:
Limiting the plurality of types of sound information to the second frequency band;
The sound field reproduction system according to claim 1. An equalizer unit that performs equalizer processing on the plurality of types of sound information passing through the first filter and the plurality of types of sound information passing through the second filter using the same parameter value,
The sound field reproduction system according to any one of claims 1 to 4. A first gain unit that applies a gain to the plurality of types of sound information corresponding to each speaker with the same gain value after passing 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 comprising
The sound field reproduction system according to any one of claims 1 to 5. A first filter and a second filter for respectively limiting a plurality of types of sound information to different frequency bands; and a plurality of types of the sound information passing through the first filter and the plurality of types of sound information passing through the second filter. A plurality of first speakers that emit at least 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 have passed through the second filter to the plurality of areas. A storage unit for storing a plurality of sets of the transfer function of the first filter and the transfer function of the second filter, and a plurality of sets stored in the storage unit when receiving an input for designating a sound field to be reproduced. A sound field reproduction system including a transfer function set according to the input selected from among the transfer function sets described above and applied to the first filter and the second filter. A field reproduction method,
Applying the set of transfer functions to the first filter and the second filter by the applying unit;
Limiting the plurality of types of sound information to different frequency bands by the first filter and the second filter,
The at least 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 first filter and the transfer function of the second filter are at least one first control point for the first frequency band in each of the plurality of areas, and the first frequency band A plurality of second control points targeting a higher second frequency band than the first control point are set, 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 the user can listen to the sound.
In the emitting step, one of the plurality of types of sound information is independently listened to in each of the plurality of areas based on the sound information emitted from each of the first speakers and each of the second speakers. A sound field that allows the sound field specified by the input to be reproduced,
Sound field reproduction method. Among 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 is larger than the number of speakers that contribute 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 includes:
Emitting sound information including at least the second frequency band higher than the first frequency band;
The sound field reproduction method according to claim 8. The first filter includes:
Limiting the plurality of types of sound information to the first frequency band,
The second filter includes:
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. The method further includes equalizing the plurality of types of sound information passed through the first filter and the plurality of types of sound information passed through the second filter using the same parameter value.
The sound field reproduction method according to any one of claims 7 to 10. Applying a gain using the same gain value to the plurality of types of sound information corresponding to each speaker that has passed through the first filter;
Applying a gain using the same gain value to the plurality of types of sound information corresponding to each speaker that has passed through the second filter;
Further comprising
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.