Speaker with microphones and sound source direction detector

Abstract

To provide a speaker with microphones and a sound source direction detector which allow a sound source direction detection system to be equipped in a vehicle without requiring a troublesome setting work.SOLUTION: The speaker with microphones includes: a speaker for outputting voice for a voice signal received through a speaker cable; first to N-th (N is an integer of at least 2) microphones set in the speaker; and a microphone voice overlapping unit for overlapping first to N-th microphone sound reception signals obtained by receiving voice by the first to N-th microphones on the speaker cable.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a speaker with a microphone and a sound source direction detection device included in a sound source direction detection system that detects the direction of a sound source. [Background technology]

[0002] In recent years, a sound source detection system has been proposed for use in vehicle driving assistance, etc., that detects the direction of a sound source from within the vehicle itself, such as the siren of an emergency vehicle or the horn of another vehicle (see, for example, Patent Document 1). In this sound source detection system, multiple microphones (hereinafter referred to as "mics") are installed on the exterior surface of the vehicle, and the direction of the sound source is detected based on multiple sound signals obtained by collecting sounds with the multiple microphones. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-67381 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned sound source detection system, the accuracy of detecting the direction of the sound source increases when the distance between the microphones is increased, but in this case, the direction of the sound source cannot be detected correctly unless the installation position (three-dimensional coordinates) of each microphone is taken into consideration. Therefore, it is necessary to set the installation position of each microphone in the system beforehand.

[0005] However, in order to perform such settings, the user or the installer must measure the installation position of each microphone and input the measurement results into the system, which is a cumbersome task.

[0006] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide a speaker with microphone and a sound source direction detection device that enable a sound source detection system to be mounted in a vehicle without requiring troublesome setting work. [Means for solving the problem]

[0007] The invention described in claim 1 comprises a speaker that outputs audio corresponding to an audio signal input via a speaker cable, first to Nth microphones (N is an integer equal to or greater than 2) installed on the speaker, and a microphone sound superimposition unit that superimposes first to Nth microphone audio signals obtained by receiving audio with the first to Nth microphones onto the speaker cable.

[0008] The invention described in claim 4 is a sound source direction detection device that detects the direction of a sound source, and includes a connection unit to which speakers on which 1st to Nth microphones (N is an integer equal to or greater than 2) are installed are electrically connected, an amplifier that amplifies an audio signal and supplies the amplified audio signal to the connection unit as a speaker drive signal, an extraction unit that extracts 1st to Nth microphone received signals from the electrical signals obtained by receiving sound from the 1st to Nth microphones respectively and supplied to the connection unit, and a direction detection circuit that detects the direction of the sound source based on the 1st to Nth microphone received signals extracted by the extraction unit. [Brief description of the drawings]

[0009] [Figure 1] 1 is a block diagram showing a configuration of a sound source direction detection system 100 mounted on a vehicle. [Diagram 2] 1 is a perspective view showing a schematic arrangement of the positions of a car audio device 10, speaker sets 20a to 20d, and a sound source direction detection section 30 as viewed from above a vehicle 200. FIG. [Diagram 3] FIG. 13 is a diagram showing the positional relationship between microphones M1 to M4 installed on speakers SP of speaker sets 20a to 20d when installed on speaker fixing parts MPa to MPd, respectively. [Figure 4] 1 is a block diagram showing an example of the internal configuration of a microphone sound superimposing unit MSP included in a speaker set 20a. [Diagram 5] 2 is a block diagram showing an example of the configuration of a sound source direction detection unit 30. FIG. [Figure 6]FIG. 2 is a diagram showing an example of the contents stored in a memory 306a. [Figure 7] FIG. 13 is a diagram showing the positional relationship when one microphone M1 is installed on each speaker SP of speaker sets 20a to 20d in a state where the speakers are installed on speaker fixing parts MPa to MPd, respectively. [Figure 8] FIG. 13 is a diagram showing the positional relationship when two microphones M1 are installed on the speakers SP of each of the speaker sets 20a to 20d in a state where the speakers are installed on the speaker fixing parts MPa to MPd, respectively. [Figure 9] 1 is a diagram showing the positional relationship between microphones M1 to M4 installed on a speaker SP having a frame fm whose surface is composed of a concave (or convex) area AR1 and a convex (or concave) area AR2. [Figure 10A] 10 is a diagram showing the shape of the surface of the frame fm of the speaker SP when the area AR1 of the frame fm is convex and the area AR2 is concave, as viewed from the direction of the white arrow in FIG. [Figure 10B] 10 is a diagram showing the shape of the surface of the frame fm of the speaker SP when the area AR1 of the frame fm is concave and the area AR2 is convex, as viewed from the direction of the white arrow in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Preferred embodiments of the present invention will now be described in detail.

[0011] FIG. 1 is a block diagram showing the configuration of a sound source direction detection system 100 mounted on a vehicle.

[0012] The sound source direction detection system 100 includes a car audio device 10, speaker sets 20a to 20d with microphones, and a sound source direction detection unit 30.

[0013] The car audio device 10 includes a playback device that plays back music signals from a CD, DVD, Blu-ray disc, hard disk, semiconductor, etc., and an FM / AM receiver (none of which are shown in the figures).The car audio device 10 further includes BTL connection amplifiers 10a-10d that individually amplify four-channel audio signals output from the playback device or FM / AM receiver as described above and output them as BTL (Bridged Transformer Less).

[0014] The BTL connection amplifiers 10a to 10d generate four-channel amplified audio signals as speaker driving signals by amplifying the four-channel audio signals individually, and supply the amplified audio signals to the connectors CN1 to CN4 as BTL output audio signals, respectively.

[0015] 1, one end of each of the speaker cables SC1 to SC4 is connected to the connectors CN1 to CN4, and the other end of each of the speaker cables SC1 to SC4 is connected to a speaker set 20a to 20d. Each of the speaker cables SC1 to SC4 actually includes two signal lines, each of which is made up of at least a positive core wire and a negative core wire.

[0016] Therefore, the BTL output audio signals output from the BTL connection amplifiers 10a to 10d are supplied to the speaker sets 20a to 20d via the connectors CN1 to CN4 and the speaker cables SC1 to SC4.

[0017] Each of the speaker sets 20a to 20d has the same internal configuration, that is, a connector CN to which a speaker cable is connected, a speaker SP, and a microphone sound superimposing unit MSP. The speaker SP of each of the speaker sets 20a to 20d has a structure that allows it to be attached to speaker fixing parts provided at four predetermined locations in the vehicle cabin.

[0018] FIG. 2 is a schematic perspective view showing an example of the installation positions of the car audio device 10, speaker sets 20a to 20d, and sound source direction detection section 30, as viewed from above the vehicle 200. As shown in FIG.

[0019] As shown in Fig. 2, the car audio device 10 and the sound source direction detection unit 30 are housed in an instrument panel of the vehicle 200. According to the example shown in Fig. 2, the driver's side door FR of the front doors of the vehicle 200 is provided with a speaker fixing part MPa to which the speaker SP of the speaker set 20a can be attached. The passenger's side door FL of the front doors of the vehicle 200 is provided with a speaker fixing part MPb to which the speaker SP of the speaker set 20b can be attached. The rear right door RR of the rear doors of the vehicle 200 is provided with a speaker fixing part MPc to which the speaker SP of the speaker set 20c can be attached. Furthermore, the rear left door RL of the rear doors of the vehicle 200 is provided with a speaker fixing part MPd to which the speaker SP of the speaker set 20d can be attached. Therefore, in the interior of the vehicle 200, the speakers SP of the speaker sets 20a to 20d are attached to the speaker fixing parts MPa to MPd, respectively.

[0020] Here, the speakers SP of each of the speaker sets 20a to 20d attached to the speaker fixing parts MPa to MPd, respectively, output sound based on the BTL output audio signal received via the speaker cable and the connector CN.

[0021] Each of the speakers SP of the speaker sets 20a to 20d is a speaker with microphones, in which four microphones M1 to M4 are installed.

[0022] FIG. 3 is a diagram showing the positional relationship between the microphones M1 to M4 installed on the speakers SP of the speaker sets 20a to 20d when installed on the speaker fixing parts MPa to MPd, respectively.

[0023] As shown in FIG. 3, microphones M1 to M4 (indicated by ●) are installed on the surface of a frame fm that supports the edge of a vibrating body dp of a speaker SP, with each sound-receiving vibrating body exposed to the interior of the vehicle.

[0024] As shown in FIG. 3, the microphones M1 to M4 are installed on the surface of the frame fm at positions different in height from the floor inside the vehicle cabin, with the speaker SP attached to the speaker fixing portion.

[0025] This makes it possible to make at least three of the distances in the height direction from each of the microphones M1 to M4 to the sound source different, thereby improving the accuracy of detecting the direction of the sound source.

[0026] In order to improve the accuracy of detecting the direction of the sound source, it is desirable to set the distance between the microphones as wide as possible. Therefore, in the example shown in Fig. 3, two of the microphones M1 to M4, M1 and M3, are placed on diagonal lines sandwiching the vibrating body dp.

[0027] The microphones M1 to M4 supply microphone reception signals s1 to s4 obtained by receiving sounds respectively to a microphone sound superimposing section MSP.

[0028] The microphone sound superimposing unit MSP superimposes the serial transmission signal ms, which is a serialization of the digital signals based on the microphone received signals s1 to s4 in the form of a differential signal with a frequency higher than the audible band (for example, 20 Hz to 20 KHz), onto the speaker cable via the connector CN. The microphone sound superimposing unit MSP is constructed, for example, in a semiconductor IC provided on a printed circuit board installed on the magnet of the speaker SP or on a frame part supporting the magnet.

[0029] FIG. 4 is a block diagram showing an example of the internal configuration of the microphone sound superimposing unit MSP included in the speaker set 20a out of the speaker sets 20a to 20d.

[0030] In the example shown in Fig. 4, the microphone sound superimposing section MSP includes a low-pass filter 51, a constant voltage circuit 52, a microphone driver 53, AD converters 54a to 54d, a serial conversion circuit 55, a differential signal conversion circuit 56, and a high-pass filter 57. The high-pass filter may be abbreviated as HPF hereinafter. In Fig. 4, the speaker cable SC1 connected to the speaker set 20a includes a positive core wire L1 and a negative core wire L2.

[0031] The low-pass filter 51 extracts a DC or low-frequency voltage close to DC from the negative core wire L2 and supplies it to the constant voltage circuit 52. That is, while the BTL connection amplifier (10a) is outputting a BTL output audio signal representing silence, a predetermined DC voltage (e.g., 7 volts) is superimposed on the BTL output audio signal. Therefore, the low-pass filter 51 extracts this DC voltage from the negative core wire L2. Hereinafter, the low-pass filter may also be abbreviated to LPF. The constant voltage circuit 52 may also include a rectifier circuit composed of a diode, a capacitor, etc., so as to be able to generate a DC voltage even while the BTL connection amplifier (10a) is outputting a low-frequency audio signal superimposed on a predetermined DC voltage.

[0032] The constant voltage circuit 52 receives the voltage supplied from the LPF 51, and generates a power supply voltage with a constant voltage value for operating the microphone driver 53, the AD converters 54a to 54d, the serial conversion circuit 55, the differential signal conversion circuit 56, and the HPF 57 based on this voltage.

[0033] That is, the LPF 51 and the constant voltage circuit 52 function as a power supply circuit that generates a power supply voltage based on the BTL output audio signal transmitted through the speaker cable.

[0034] The microphone driver 53, the AD converters 54a to 54d, the serial conversion circuit 55, the differential signal conversion circuit 56, and the HPF 57 receive the power supply voltage supplied from the constant voltage circuit 52 and perform the following operations.

[0035] The microphone driver 53 amplifies the microphone reception signals s1 to s4 supplied from the microphones M1 to M4 individually and supplies the amplified signals to the AD converters 54a to 54d.

[0036] The AD converters 54a to 54d convert the analog microphone reception signals s1 to s4 into digital reception signals d1 to d4 in digital signal form, respectively, and supply the digital reception signals to the serial conversion circuit 55.

[0037] The serial conversion circuit 55 receives a clock signal CLK having a frequency higher than the audible band, for example, 100 KHz, and generates a multiplexed serial signal sd by sequentially connecting the digital received audio signals d1 to d4 in a serial form in accordance with the clock signal CLK, and supplies the multiplexed serial signal sd to a differential signal conversion circuit 56.

[0038] The differential signal conversion circuit 56 converts the serial signal sd into a differential signal format to obtain serial transmission signals md1 and md2, which are then supplied to the HPF 57.

[0039] HPF57 passes frequency components higher than the audible range from each of serial transmission signals md1 and md2, and supplies the serial transmission signal md1 to the connector CN to which the positive core wire L1 of the speaker cable SC1 is connected, and supplies the serial transmission signal ms2 to the connector CN to which the negative core wire L2 of the speaker cable SC1 is connected.

[0040] Therefore, with the configuration shown in FIG. 4, the microphone sound superimposing unit MSP superimposes the serial transmission signals ms1 and ms2 in the form of differential signals representing the microphone received sound signals s1 to s4 onto the speaker cable SC1 via the connector CN.

[0041] The sound source direction detector 30 is connected to the connectors CN1 to CN4, and receives the electrical signals flowing through the speaker cables SC1 to SC4 via the connectors CN1 to CN4. The sound source direction detector 30 detects the direction of the sound source of the sound generated outside or inside the vehicle 200 based on the serial transmission signals flowing through the speaker cables SC1 to SC4, and outputs a sound source direction signal SSD indicating the direction of the sound source.

[0042] FIG. 5 is a block diagram showing an example of the configuration of the sound source direction detection unit 30. As shown in FIG.

[0043] In the example shown in FIG. 5, the sound source direction detection unit 30 includes HPFs 301a to 301d, digital conversion circuits 302a to 302d, separation circuits 303a to 303d, a direction detection circuit 304, an operation unit 305, and an installation position acquisition unit 306.

[0044] The HPF 301a is connected to the core wires L1 and L2 of the speaker cable SC1, extracts signals of frequencies higher than the audible band from the electric signals flowing through the core wires L1 and L2, and supplies each of them to the digital conversion circuit 302a. Note that the core wires L1 and L2 of the speaker cable SC1 carry the BTL output audio signal in the audible band output from the BTL connection amplifier 10a, and the serial transmission signals ms1 and ms2 in the inaudible band output from the microphone sound superimposing unit MSP of the speaker set 20a. Therefore, the HPF 301a extracts the serial transmission signals ms1 and ms2 sent from the microphone sound superimposing unit MSP of the speaker set 20a from the core wires L1 and L2 of the speaker cable SC1, and supplies each of them to the digital conversion circuit 302a.

[0045] The HPF 301b is connected to the core wires L1 and L2 of the speaker cable SC2, extracts signals of frequencies higher than the audible band from the electric signals flowing through the core wires L1 and L2, and supplies each of them to the digital conversion circuit 302b. Note that the core wires L1 and L2 of the speaker cable SC2 carry the BTL output audio signal in the audible band output from the BTL connection amplifier 10b, and the serial transmission signals ms1 and ms2 in the inaudible band output from the microphone sound superimposing unit MSP of the speaker set 20b. Therefore, the HPF 301b extracts the serial transmission signals ms1 and ms2 sent from the microphone sound superimposing unit MSP of the speaker set 20b from the core wires L1 and L2 of the speaker cable SC2, and supplies each of them to the digital conversion circuit 302b.

[0046] The HPF 301c is connected to the core wires L1 and L2 of the speaker cable SC3, extracts signals of frequencies higher than the audible band from the electric signals flowing through the core wires L1 and L2, and supplies each of them to the digital conversion circuit 302c. Note that the core wires L1 and L2 of the speaker cable SC3 carry the BTL output audio signal in the audible band output from the BTL connection amplifier 10c, and the serial transmission signals ms1 and ms2 in the inaudible band output from the microphone sound superimposing unit MSP of the speaker set 20c. Therefore, the HPF 301c extracts the serial transmission signals ms1 and ms2 sent from the microphone sound superimposing unit MSP of the speaker set 20c from the core wires L1 and L2 of the speaker cable SC3, and supplies each of them to the digital conversion circuit 302c.

[0047] The HPF 301d is connected to the core wires L1 and L2 of the speaker cable SC4, extracts signals of frequencies higher than the audible band from the electric signals flowing through the core wires L1 and L2, and supplies each of them to the digital conversion circuit 302d. Note that the core wires L1 and L2 of the speaker cable SC4 carry the BTL output audio signal in the audible band output from the BTL connection amplifier 10d, and the serial transmission signals ms1 and ms2 in the inaudible band output from the microphone sound superimposing unit MSP of the speaker set 20d. Therefore, the HPF 301d extracts the serial transmission signals ms1 and ms2 sent from the microphone sound superimposing unit MSP of the speaker set 20d from the core wires L1 and L2 of the speaker cable SC4, and supplies each of them to the digital conversion circuit 302d.

[0048] The digital conversion circuit 302a converts the signal based on the differential voltage of the serial transmission signals ms1 and ms2 supplied from the HPF 301a, and restores the serial signal sda before being converted by the differential signal conversion circuit 56. The digital conversion circuit 302a restores the serial signal sda representing the digital received signals d1 to d4 obtained by the microphones M1 to M4 of the speaker set 20a through the conversion process, and supplies the serial signal sda to the separation circuit 303a. The digital conversion circuit 302b performs the above-mentioned conversion process on the serial transmission signals ms1 and ms2 supplied from the HPF 301b, thereby restoring the serial signal sdb representing the digital received signals d1 to d4 obtained by the microphones M1 to M4 of the speaker set 20b. The digital conversion circuit 302b supplies the restored serial signal sdb to the separation circuit 303b. The digital conversion circuit 302c performs the above-mentioned conversion process on the serial transmission signals ms1 and ms2 supplied from the HPF 301c to restore a serial signal sdc representing the digital received sound signals d1 to d4 obtained by the microphones M1 to M4 of the speaker set 20c. The digital conversion circuit 302c supplies the restored serial signal sdc to the separation circuit 303c. The digital conversion circuit 302d performs the above-mentioned conversion process on the serial transmission signals ms1 and ms2 supplied from the HPF 301d to restore a differential serial signal sdd representing the digital received sound signals d1 to d4 obtained by the microphones M1 to M4 of the speaker set 20d. The digital conversion circuit 302d supplies the restored serial signal sdd to the separation circuit 303d.

[0049] The separation circuit 303a separates and extracts the digital received signals d1 to d4 acquired by the microphones M1 to M4 of the speaker set 20a from the serial signal sda supplied from the digital conversion circuit 302a, and supplies them as microphone received signals Sa1 to Sa4 to the direction detection circuit 304. The separation circuit 303b separates and extracts the digital received signals d1 to d4 acquired by the microphones M1 to M4 of the speaker set 20b from the serial signal sdb supplied from the digital conversion circuit 302b, and supplies them as microphone received signals Sb1 to Sb4 to the direction detection circuit 304. The separation circuit 303c separates and extracts the digital received signals d1 to d4 acquired by the microphones M1 to M4 of the speaker set 20c from the serial signal sdc supplied from the digital conversion circuit 302c, and supplies them as microphone received signals Sc1 to Sc4 to the direction detection circuit 304. The separation circuit 303d separates and extracts the digital received signals d1 to d4 acquired by the microphones M1 to M4 of the speaker set 20d from the serial signal sdd supplied from the digital conversion circuit 302d, and supplies them to the direction detection circuit 304 as microphone received signals Sd1 to Sd4, respectively.

[0050] In this manner, in the sound source direction detection unit 30, an extraction unit composed of the HPFs 301a to 301d, the digital conversion circuits 302a to 302d, and the separation circuits 303a to 303d extracts 16 microphone signals obtained by receiving sound at the microphones M1 to M4 of each of the speaker sets 20a to 20d from the electrical signals flowing through each of the connectors CN1 to CN4.

[0051] The operation unit 305 accepts an operation by the user to specify the model of the vehicle 200 , and supplies the installation position acquisition unit 306 with model information indicating the model (type) of the vehicle 200 .

[0052] The installation position acquisition unit 306 includes a memory 306a and a microphone position identification unit 306b.

[0053] 6, the memory 306a stores information expressing the installation position of each of the speaker fixing parts MPa to MPd in ​​the vehicle for each type of vehicle in three-dimensional coordinates (X, Y, Z). Here, the installation position of each of the speaker fixing parts MPa to MPd indicates a relative position with respect to a predetermined reference position (for example, the position of the driver's seat) in the interior of the vehicle 200.

[0054] The installation position acquisition unit 306 reads out from the memory 306a information indicating the installation position of each of the speaker fixing parts (MPa to MPd) corresponding to the vehicle model indicated by the vehicle model information supplied from the operation unit 305. The microphone position identification unit 306b identifies the installation position (three-dimensional coordinates) of each of the microphones M1 to M4 shown in FIG. 3 that are installed on the speaker SP of each of the speaker sets 20a to 20d, based on the installation position information of the speaker fixing parts read out from the memory 306a. The installation position acquisition unit 306 supplies the direction detection circuit 304 with microphone installation position information indicating the installation position of each of the 16 microphones, consisting of the microphones M1 to M4 included in each of the speaker sets 20a to 20d, identified by the microphone position identification unit 306b.

[0055] The direction detection circuit 304 first detects the amplitude difference and phase difference (difference in arrival time of sound from the sound source) between the microphone reception signals Sa1-Sa4, Sb1-Sb4, Sc1-Sc4, and Sd1-Sd4. Next, the direction detection circuit 304 identifies the direction of the sound source generated inside or outside the vehicle based on the detected amplitude difference and phase difference between the microphone reception signals and the installation positions of each of the 16 microphones indicated by the microphone installation position information. The direction detection circuit 304 may determine whether the sound source is inside or outside the vehicle based on the microphone reception signals (Sa1-Sa4, Sb1-Sb4, Sc1-Sc4, Sd1-Sd4), and identify the sound source direction using an algorithm optimal for identifying the sound source direction inside the vehicle or an algorithm optimal for identifying the sound source direction outside the vehicle according to the determination result. The direction detection circuit 304 may also detect the direction of the sound source based on the microphone reception signals and microphone installation position information described above in accordance with a whitening cross-correlation (cross-power spectrum phase analysis) method.

[0056] The direction detection circuit 304 outputs a sound source direction signal SSD indicating the sound source direction identified as described above.

[0057] As described above in detail, the sound source direction detecting system 100 employs the speaker SP, on which the four microphones M1 to M4 are installed, as an in-vehicle speaker.

[0058] Here, the in-vehicle speaker is provided, for example, on the interior surface of the vehicle door, and is attached to a speaker fixing part whose installation position is predetermined for each vehicle model. Therefore, based on the position of the speaker fixing part, the installation positions of the microphones M1 to M4 installed on the speaker SP can be known.

[0059] Therefore, in the sound source direction detection system 100, information indicating the installation position (three-dimensional coordinates) of each of the speaker fixing parts MPa to MPd is registered in advance in the memory 306a of the installation position acquisition unit 306 in association with each vehicle model as shown in FIG. 6. Here, the installation position acquisition unit 306 first reads out the installation position (three-dimensional coordinates) of each of the speaker fixing parts MPa to MPd corresponding to the vehicle model of the vehicle (200) from the memory 306a. Then, the microphone position identification unit 306b of the installation position acquisition unit 306 identifies the installation positions (three-dimensional coordinates) of each of the microphones M1 to M4 installed on the speaker SP attached thereto from the installation positions of each of the speaker fixing parts MPa to MPd. That is, in a state where the microphones M1 to M4 are fixed to the speaker fixing parts, the relative positions of each of the microphones M1 to M4 on the frame fm surface of each speaker SP are known. Therefore, if the installation position of the speaker mounting part is known from the registered contents of the memory 306a, it is possible to specify the installation positions of each speaker installed on the speaker SP attached to that speaker mounting part.

[0060] In this way, in the sound source direction detection system 100, the microphones M1 to MP4 for detecting the sound source direction are installed and integrated into the vehicle speaker SP, making it possible to obtain information indicating the installation position of each microphone without the need to measure the installation position (three-dimensional coordinates) of each microphone and input the measurement results.

[0061] Therefore, by using the acquired information indicating the installation position of each microphone, the sound source direction detection unit 30 can perform highly accurate sound source direction detection based on the microphone reception signals obtained by receiving sound with multiple microphones installed at a distance from each other.

[0062] Furthermore, in the sound source direction detection system 100, microphone reception signals s1 to s4 obtained by receiving sounds with microphones M1 to M4 installed in a speaker SP that generates sounds corresponding to audio signals input via a speaker cable (for example, SC1) are superimposed on the speaker cable and transmitted to the sound source direction detection unit 30. Specifically, a microphone sound superimposition unit MSP installed in the speaker SP serializes the microphone reception signals s1 to s4 in the form of differential signals with frequencies higher than the audible band, and superimposes the serial transmission signals on the speaker cable.

[0063] This eliminates the need for dedicated wiring for transmitting the microphone pickup signals. Furthermore, by attaching the speaker SP to the speaker fixing portion, the installation of multiple microphones can be completed at the same time, eliminating the need for the installation of the dedicated cables and microphones in the vehicle 200.

[0064] Therefore, the installation work for introducing the sound source direction detection system 100 into the vehicle 100 can be simplified, and the cost can be reduced by the amount of dedicated wiring not required. In the above embodiment, the installation position of each microphone is acquired based on the installation position information of each speaker fixing part (MPa to MPd) for each vehicle type registered in advance in the memory 306a. However, there is a case where the vehicle type corresponding to the actual vehicle 200 is not registered in the memory 306a. In this case, when the vehicle type indicated by the vehicle type information supplied from the operation unit 305 is not registered in the memory 306a, the installation position acquisition unit 306 may output the test sound to each speaker SP of the speaker sets 20a to 20d in sequence, and identify the installation position of each microphone M1 to M4 based on a comparison between the phase or amplitude of each microphone reception signal (Sa1 to Sa4, Sb1 to Sb4, Sc1 to Sc4, Sd1 to Sd4) obtained by receiving the sound with the microphones M1 to M4 installed in each speaker SP and the original signal of the test sound.

[0065] In addition, in an example of a sound source direction detection system 100 shown in Figures 1 and 2, the sound source direction is detected based on 16 microphone signals obtained by receiving sound using a total of 16 microphones consisting of four microphones M1 to M4 installed on each of the four speakers SP.

[0066] However, the number of such speakers with microphones SP is not limited to four, and may be four or more, or may be one to three.

[0067] Furthermore, as long as at least four microphones are installed on the multiple speakers SP in the sound source direction detection system 100, the multiple speakers SP may include a speaker SP without a microphone. That is, at least four microphones may be installed on one or more speakers SP. In other words, at least four microphones may be installed in the vehicle. In this case, the sound source direction detection unit 30 detects the sound source direction based on a group of microphone reception signals obtained by receiving sound with at least four microphones and the installation positions of each microphone.

[0068] Furthermore, when four or more speakers SP are employed as the sound source direction detection system 100, at least one microphone should be provided for each speaker SP of the speaker sets 20a to 20d.

[0069] For example, as shown in Fig. 7, only a single microphone M1 is installed on the frame fm of each speaker SP of the speaker sets 20a to 20d. In this case, it is preferable that the microphone M1 is installed on the frame fm of the speaker SP so that the height positions of the microphones M1 from the floor of the vehicle interior are different when each speaker SP is attached to the corresponding speaker fixing parts MPa to MPd. For example, as shown in Fig. 7, the height positions of the microphones M1 installed on the speakers SP of each speaker set 20a to 20d from the floor of the vehicle interior are as follows: 20a M1:h1 20b M1:h2 20c M1:h3 Let's say M1:h4 in 20d.

[0070] That is, when the distances from three of the four microphones (M1) installed on the speaker sets 20a to 20d to the sound source are the same, two directions that are normal directions of the virtual plane that includes the three microphones can be candidates for the direction of the sound source, but by installing one of the four microphones so that the installation point of one microphone is not included in the virtual plane defined by the installation points of the other three microphones, the distances from the three microphones included in the virtual plane to the sound source and the distance from the other microphone that does not exist on the virtual plane to the sound source will necessarily be different, so it is possible to determine which of the two sound source direction candidates is the correct sound source direction. Therefore, it is possible to improve the detection accuracy of the sound source direction.

[0071] In other words, in order to further improve the accuracy of detecting the direction of the sound source, the installation point on the three-dimensional coordinate system of, for example, one microphone M1 out of the four microphones M1 to M4 installed on each of four or more speakers SP may be set to a position that is not included on the plane defined by the installation points of the other microphones M2 to M4.

[0072] Also, for example, as shown in FIG. 8, only two microphones M1 and M3 may be installed on the frame fm of the speaker SP of each of the speaker sets 20a to 20d. In this case, the microphones M1 and M3 are installed on the surface of the frame fm of each speaker SP, diagonally across the vibrating body dp. Furthermore, the microphones M1 and M3 are installed on the frame fm of the speaker SP such that the height positions of the pair of microphones (M1, M3) from the floor of the vehicle cabin are different when the pair of microphones (M1, M3) are attached to the respective speaker fixing parts MPa to MPd. For example, as shown in FIG. 8, the height positions of the pair of microphones (M1, M3) installed on the speaker SP of each of the speaker sets 20a to 20d from the floor of the vehicle cabin are 20a M1, M3:h1, h8 20b M1, M3:h2, h7 20c M1, M3:h3, h6 20d M1, M3:h4, h5 Let us assume that.

[0073] In the above embodiment, no mention is made of the surface shape of the frame fm of the speaker SP on which each microphone (M1 to M4) is mounted, but the surface area of ​​the frame fm on which at least one of the multiple microphones is mounted may be concave or convex.

[0074] For example, as a speaker SP, as shown in FIG. 9, a surface of an area AR1 in a frame fm in which a microphone M1 is installed has one of a concave and a convex shape, and a surface of an area AR2 in which microphones M2 to M4 are installed has the other of a concave and a convex shape.

[0075] Fig. 10A is a diagram showing the shape of the surface of frame fm of speaker SP shown in Fig. 9 when region AR1 of frame fm is convex and region AR2 is concave, as viewed from the direction of the white arrow in Fig. 9. Also, Fig. 10B is a diagram showing the shape of the surface of frame fm of speaker SP when region AR1 of frame fm is concave and region AR2 is convex, as viewed from the direction of the white arrow in Fig. 9.

[0076] As shown in Fig. 10A, when the surface of area AR2 is convex and the surface of area AR1 is concave, the position of the sound receiving surface (vibrator) of each of microphones M2 to M4 is closer to the sound source than microphone M1. On the other hand, as shown in Fig. 10B, when the surface of area AR2 is concave and the surface of area AR1 is convex, the position of the sound receiving surface of each of microphones M2 to M4 is farther from the sound source than microphone M1.

[0077] In other words, by installing the microphones M1 to M4 on the speaker SP in the form shown in Figure 9, Figure 10A or Figure 10B, the installation point (three-dimensional coordinates) of one of the four microphones M1 to M4, microphone M1, is not included in the plane defined by the installation points of the other three microphones M2 to M4.

[0078] As a result, even if the distance from the sound source to the sound receiving surface of each of the three microphones M2 to M4 is the same, it is possible to make this distance different from the distance from the sound source to microphone M1, thereby improving the accuracy of detecting the direction of the sound source.

[0079] In short, the sound source direction detection system 100 for detecting the direction of a sound source inside or outside the vehicle may include a speaker group including at least one speaker (SP) each of which can be attached to a speaker fixing part (e.g., MPa to MPd) inside the vehicle and has a plurality of microphones (e.g., M1 to M4) installed thereon, and a microphone installation position acquisition part and a direction detection part described below. The microphone installation position acquisition part (306) identifies the installation positions of the microphones based on the installation positions of the speaker fixing parts, and acquires microphone installation position information indicating the installation positions of the microphones. The direction detection part (30) detects the direction of the sound source based on microphone reception signals (e.g., Sa1 to Sa4, Sb1 to Sb4, Sc1 to Sc4, Sd1 to Sd4) obtained by receiving sound with each of the plurality of microphones, and the installation positions of the microphones indicated by the microphone installation position information described above.

[0080] Furthermore, the speaker with microphone used in the sound source direction detection system 100 may include a speaker (SP) that outputs sound corresponding to an audio signal received via a speaker cable (e.g., SC1), first to Nth (N is an integer equal to or greater than 2) microphones (e.g., M1 to M4) installed on the speaker, and a microphone sound superimposition unit (MSP) that superimposes the first to Nth microphone sound signals (e.g., s1 to s4) obtained by receiving sound with the first to Nth microphones onto the speaker cable. [Explanation of symbols]

[0081] 10 Audio Equipment 20a~20d Speaker set 30 Sound source direction detection unit 304 Direction Detection Circuit 305 Operation section 306 Installation position acquisition part M1~M4 Microphones MSP microphone sound superimposition section SP Speaker

Claims

1. a speaker that outputs sound corresponding to an audio signal input via a speaker cable; First to Nth microphones (N is an integer of 2 or more) installed on the speaker; a microphone sound superimposing unit that superimposes first to Nth microphone sound signals obtained by receiving sounds with the first to Nth microphones onto the speaker cable.

2. The speaker with microphone described in claim 1, characterized in that the microphone sound superimposition unit digitizes each of the first to Nth microphone received signals and further serializes them in the form of a differential signal at a frequency higher than the audible range to generate a serial transmission signal, which is superimposed on the speaker cable.

3. The audio signal is a signal output from a BTL amplifier, 3. The speaker with microphone according to claim 1, wherein the microphone sound superimposing unit includes a power supply circuit that generates a power supply voltage for operating the microphone sound superimposing unit from a voltage applied to the speaker cable by the BTL amplifier.

4. A sound source direction detection device for detecting the direction of a sound source, a connection section to which a speaker on which first to Nth microphones (N is an integer of 2 or more) are installed is electrically connected; an amplifier that amplifies an audio signal and supplies the amplified audio signal to the connection portion as a speaker drive signal; an extracting unit that extracts first to Nth microphone pickup signals from the electrical signals obtained by pickup with the first to Nth microphones and supplied to the connection unit; a direction detection circuit for detecting the direction of the sound source based on the first to Nth microphone signals extracted by the extraction unit.

5. The sound source direction detection device according to claim 4, characterized in that the electrical signal is a serial transmission signal in which the digitized first to Nth microphone pickup signals are serialized in the form of a differential signal having a frequency higher than the audible band.

6. 6. The sound source direction detecting device according to claim 4, wherein the audio signal is a signal output from a BTL amplifier.

7. the extraction unit is a high-pass filter that extracts a serial transmission signal having a frequency component higher than an audible band from the electrical signal supplied to the connection unit; 7. The sound source direction detection device according to claim 5, further comprising a demodulation circuit that performs demodulation processing on the extracted serial transmission signal to restore the first to Nth received sound signals.

8. 3. The speaker with microphone according to claim 2, wherein the frequency higher than the audible band is a frequency higher than 100 KHz.

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