Sound processing device and vehicle-mounted audio system

Abstract

Thus, interference sound that can be heard in the first partition can be reduced while the interference effect is maintained. An audio processing device (30) has a first filter bank (FG1) and a second filter bank (FG2). The first filter group (FG1) controls a first interference sound output from a first speaker set (41) disposed in a first section (ZN1). The second filter group (FG2) controls a second interference sound output from a second speaker set (42) disposed in a second section (ZN2) close to the first section (ZN1). The characteristics of the first filter bank (FG1) and the characteristics of the second filter bank (FG2) are set so that the sum of the volume of the first disturbance sound and the volume of the second disturbance sound that can be heard in the second section (ZN2) is greater than the sum of the volume of the first disturbance sound and the volume of the second disturbance sound that can be heard in the first section (ZN1).

Description

Technical Field

[0001] The invention relates to a sound processing device and a vehicle-mounted audio system. Background Art

[0002] Conventionally, there is known a technique for masking a call in order to protect the driver's privacy during a hands-free call made by a driver of a vehicle, etc. For example, Patent Document 1 discloses a voice playback device that plays a received voice signal in a clear voice zone and plays a masking sound that masks the voice in a voice masking zone.

[0003] Patent Document 1: Japanese Patent Application No. 2018-506080

[0004] In the voice playback device described in Patent Document 1, an analysis signal is generated based on the spectrum and / or time characteristics of the received call voice signal. The voice playback device generates a signal representing the masking sound based on the generated analysis signal. The generated signal is output to a speaker configured in a voice masking-zone. The speaker outputs the masking sound. However, the masking sound has a low effect on masking the voice in the low frequency range, so the masking sound needs to be increased, especially in the low frequency range. As a result, the previous voice playback device has the problem of causing discomfort to the driver and fellow passengers. Summary of the invention

[0005] In view of the above circumstances, one embodiment of the present invention aims to obtain a sound processing device that can reduce the interfering sound audible in the first section while maintaining the interfering effect.

[0006] In order to solve the above problems, one embodiment of the present invention involves a sound processing device comprising: a first filter group, which is input with a first sound signal, and includes one or more filters for controlling a first interfering sound output from a first speaker set including one or more speakers arranged in a first partition; and a second filter group, which is input with the first sound signal, and includes one or more filters for controlling a second interfering sound output from a second speaker set including one or more speakers arranged in a second partition close to the first partition, wherein the characteristics of the first filter group and the characteristics of the second filter group are set so that the total volume of the first interfering sound and the volume of the second interfering sound audible in the second partition is greater than the total volume of the first interfering sound and the volume of the second interfering sound audible in the first partition.

[0007] An in-vehicle audio system according to one embodiment of the present invention comprises: a first speaker set arranged in a first partition; a second speaker set arranged in a second partition close to the first partition; and a sound processing device comprising a first filter group for controlling a first interfering sound output from the first speaker set, a second filter group for controlling a second interfering sound output from the second speaker set, a third filter group for controlling a first broadcast sound output from the first speaker set, and a fourth filter group for controlling a second broadcast sound output from the second speaker set, wherein the first filter group The characteristics of the filter group and the characteristics of the second filter group are set so that the total volume of the first interference sound and the volume of the second interference sound audible in the second partition is greater than the total volume of the first interference sound and the volume of the second interference sound audible in the first partition, and the characteristics of the third filter group and the characteristics of the fourth filter group are set so that the total volume of the first broadcast sound and the volume of the second broadcast sound audible in the first partition is greater than the total volume of the first broadcast sound and the volume of the second broadcast sound audible in the second partition. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a block diagram showing an example of a vehicle audio system including the sound processing device according to the first embodiment.

[0009] Figure 2 Yes means Figure 1 A configuration diagram of an example of an in-car audio system.

[0010] Figure 3 It is a front view showing an example of arrangement of the first speaker set and the second speaker set.

[0011] Figure 4 It is a plan view showing an example of arrangement of the first speaker set and the second speaker set.

[0012] Figure 5 This is an explanatory diagram for the speakers and virtual microphones arranged in the first zone and the second zone.

[0013] Figure 6 It is an explanatory diagram for the speakers and virtual microphones arranged in the first section and the second section according to the first modification.

[0014] Figure 7 It is a front view showing an example of arrangement of a first speaker set and a second speaker set according to a second modification.

[0015] Figure 8It is a front view showing an example of arrangement of the first speaker set and the second speaker set according to the third modification. DETAILED DESCRIPTION

[0016] A: First embodiment

[0017] A1: Composition of the sound processing device

[0018] Figure 1 1 is a block diagram showing an example of the in-vehicle audio system 1 including the sound processing device 30 according to the first embodiment. Figure 2 Yes means Figure 1 1 is a diagram showing a configuration of an example of an in-vehicle audio system 1. Figure 3 It is a front view showing an example of the arrangement of the first speaker set 41 and the second speaker set 42 . Figure 4 It is a plan view showing an example of the arrangement of the first speaker set 41 and the second speaker set 42 .

[0019] The in-vehicle audio system 1 is installed in a vehicle such as a car. Figure 1 and Figure 2 As shown, the in-vehicle audio system 1 includes a storage device 10 , a sound generating device 20 , a sound processing device 30 , and a speaker device 40 .

[0020] The storage device 10 is a computer-readable recording medium (for example, a non-transitory recording medium that can be read by a computer). The storage device 10 includes a nonvolatile memory and a volatile memory. Nonvolatile memory is, for example, a ROM (Read Only Memory), an EPROM (Erasable Programmable Read Only Memory), or a volatile memory.

[0021] Memory) and EEPROM (Electrically Erasable Programmable Read Only

[0022] Volatile memory is, for example, RAM (Random Access Memory).

[0023] The storage device 10 stores a program pr1 and various information. The program pr1 defines the operation of the sound generating device 20 and the sound processing device 30. The storage device 10 may store the program pr1 read from a storage device in a server (not shown). In this case, the storage device in the server is an example of a recording medium that can be read by a computer.

[0024] The sound generating device 20 and the sound processing device 30 read the program pr1 from the storage device 10. The sound generating device 20 functions as the interference signal generating unit 21 and the call signal generating unit 22 by executing the program pr1. The sound processing device 30 functions as the interference sound filter unit 31, the call sound filter unit 32, and the mixing unit 33 by executing the program pr1. At least one of the interference signal generating unit 21, the call signal generating unit 22, the interference sound filter unit 31, the call sound filter unit 32, and the mixing unit 33 can be implemented by a circuit such as a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0025] The interference signal generating unit 21 generates the first source signal SO1. The first source signal SO1 is a signal that serves as the basis for interference sound output to the second zone in such a manner that the voice of the person talking in the first zone ZN1 and the voice of the other party of the conversation are not easily heard by the person in the second zone ZN2 adjacent to the first zone ZN1. In the present embodiment, the person talking in the first zone ZN1 is assumed to be the driver of the vehicle 100, and the person in the second zone is assumed to be a fellow passenger of the vehicle 100.

[0026] The call signal generating unit 22 generates the second source signal SO2. The second source signal SO2 is a signal related to the voice of the other party of the driver who is talking in the first zone ZN1.

[0027] The interference sound filter unit 31 includes a first low-pass filter LP1, a first filter group FG1, a second filter group FG2, a first high-pass filter HP1, a first delay device DL1, a first amplifier group AG1, a second amplifier group AG2, a first mixer MX1, a second mixer MX2, a third mixer MX3, and a fourth mixer MX4. The first filter group FG1 and the second filter group FG2 are zoning filters.

[0028] The partition filter is used to control the acoustic characteristics by implementing different acoustic processing for each partition when considering the acoustic space divided into multiple partitions. The higher the frequency, the more difficult it is to adjust the acoustic characteristics. Therefore, for the partition filter, it can be said that the frequency band below 500Hz is generally effective. According to the above, only the signal of the low frequency band that is effective for controlling the acoustic characteristics is filtered, and the signal of the high frequency band is mixed with the filtered signal, thereby reducing the calculation load in the filter without losing the effect of the filter.

[0029] The first low-pass filter LP1 cuts off the high-frequency component of the first source signal SO1 to output a first low-frequency signal SL1. The first low-frequency signal SL1 is an example of a “first sound signal.” The cutoff frequency of the first low-pass filter LP1 is, for example, 500 Hz.

[0030] The first low-frequency signal SL1 is input to the first filter group FG1 and the second filter group FG2. The first low-frequency signal SL1 is a signal from which high-frequency components above the cutoff frequency are removed by the first low-pass filter LP1, thereby reducing the calculation load in the first filter group FG1 and the second filter group FG2 at the subsequent stage.

[0031] The first filter group FG1 includes a first filter FL1 and a second filter FL2. As described later, the phase characteristics and amplitude characteristics of the first filter FL1 and the second filter FL2 are calculated in the frequency domain. In order to accurately express the phase characteristics and amplitude characteristics of the filter calculated in the frequency domain, it is preferably a FIR (Finite Impulse Response) filter. Therefore, in this embodiment, FIR filters are used for the first filter FL1 and the second filter FL2, respectively.

[0032] The second filter group FG2 includes a third filter FL3 and a fourth filter FL4. As with the first filter FL1 and the second filter FL2, the third filter FL3 and the fourth filter FL4 are FIR filters.

[0033] The first high-pass filter HP1 outputs the first high-frequency signal SH1 by cutting off the low-frequency component of the first source signal SO1. The cut-off frequency of the first high-pass filter HP1 is equal to the cut-off frequency of the first low-pass filter LP1. The first delay device DL1 delays the phase of the first high-frequency signal SH1. The delay amount obtained by the first delay device DL1 is determined by considering the respective delay amounts in the first filter group FG1 and the second filter group FG2.

[0034] The first amplifier group AG1 includes a first amplifier AM1 and a second amplifier AM2. The first amplifier group AG1 is a variable gain amplifier. That is, the first amplifier AM1 and the second amplifier AM2 are variable gain amplifiers. The signal whose amplitude of the first high frequency signal SH1 is adjusted by the first amplifier AM1 and the signal output from the first filter FL1 are mixed through the first mixer MX1. The signal whose amplitude of the first high frequency signal SH1 is adjusted by the second amplifier AM2 and the signal output from the second filter FL2 are mixed through the second mixer MX2.

[0035] The second amplifier group AG2 includes a third amplifier AM3 and a fourth amplifier AM4. The second amplifier group AG2 is a variable gain amplifier. That is, the third amplifier AM3 and the fourth amplifier AM4 are variable gain amplifiers. The signal whose amplitude of the first high frequency signal SH1 is adjusted by the third amplifier AM3 and the signal output from the third filter FL3 are mixed through the third mixer MX3. The signal whose amplitude of the first high frequency signal SH1 is adjusted by the fourth amplifier AM4 and the signal output from the fourth filter FL4 are mixed through the fourth mixer MX4.

[0036] The first filter FL1 corresponds to the first speaker SP1 of the first speaker set 41. The second filter FL2 corresponds to the second speaker SP2 of the first speaker set 41. The third filter FL3 corresponds to the third speaker SP3 of the second speaker set 42. The fourth filter FL4 corresponds to the fourth speaker SP4 of the second speaker set 42.

[0037] The call tone filter unit 32 includes a second low-pass filter LP2, a third filter group FG3, a fourth filter group FG4, a second high-pass filter HP2, a second delay device DL2, a third amplifier group AG3, a fourth amplifier group AG4, a fifth mixer MX5, a sixth mixer MX6, a seventh mixer MX7, and an eighth mixer MX8. The third filter group FG3 and the fourth filter group FG4 are partition filters.

[0038] The second low-pass filter LP2 cuts off the high-frequency component of the second source signal SO2 to output a second low-frequency signal SL2. The second low-frequency signal SL2 is an example of a “second sound signal.” The cutoff frequency of the second low-pass filter LP2 is equal to the cutoff frequency of the first low-pass filter LP1.

[0039] The second low-frequency signal SL2 is input to the third filter group FG3 and the fourth filter group FG4. The second low-frequency signal SL2 is a signal obtained by removing high-frequency components above the cutoff frequency through the second low-pass filter LP2, thereby reducing the calculation load in the third filter group FG3 and the fourth filter group FG4 at the subsequent stage.

[0040] The third filter group FG3 includes a fifth filter FL5 and a sixth filter FL6. The fifth filter FL5 and the sixth filter FL6 are FIR filters, similar to the first filter FL1 to the fourth filter FL4.

[0041] The fourth filter group FG4 includes a seventh filter FL7 and an eighth filter FL8. As for the seventh filter FL7 and the eighth filter FL8, similarly to the first filter FL1 to the sixth filter FL6, FIR filters are respectively used.

[0042] The second high-pass filter HP2 outputs the second high-frequency signal SH2 by cutting off the low-frequency component of the second source signal SO2. The cut-off frequency of the second high-pass filter HP2 is equal to the cut-off frequency of the second low-pass filter LP2. The second delay device DL2 delays the phase of the second high-frequency signal SH2. The delay amount obtained by the second delay device DL2 is determined by considering the respective delay amounts in the third filter group FG3 and the fourth filter group FG4.

[0043] The third amplifier group AG3 includes a fifth amplifier AM5 and a sixth amplifier AM6. The third amplifier group AG3 is a variable gain amplifier. That is, the fifth amplifier AM5 and the sixth amplifier AM6 are variable gain amplifiers. The signal whose amplitude of the second high frequency signal SH2 is adjusted by the fifth amplifier AM5 and the signal output from the fifth filter FL5 are mixed through the fifth mixer MX5. The signal whose amplitude of the second high frequency signal SH2 is adjusted by the sixth amplifier AM6 and the signal output from the sixth filter FL6 are mixed through the sixth mixer MX6.

[0044] The fourth amplifier group AG4 includes the seventh amplifier AM7 and the eighth amplifier AM8. The fourth amplifier group AG4 is a variable gain amplifier. That is, the seventh amplifier AM7 and the eighth amplifier AM8 are variable gain amplifiers. The signal whose amplitude of the second high frequency signal SH2 is adjusted by the seventh amplifier AM7 and the signal output from the seventh filter FL7 are mixed through the seventh mixer MX7. The signal whose amplitude of the second high frequency signal SH2 is adjusted by the eighth amplifier AM8 and the signal output from the eighth filter FL8 are mixed through the eighth mixer MX8.

[0045] The fifth filter FL5 corresponds to the first speaker SP1 of the first speaker set 41. The sixth filter FL6 corresponds to the second speaker SP2 of the first speaker set 41. The seventh filter FL7 corresponds to the third speaker SP3 of the second speaker set 42. The eighth filter FL8 corresponds to the fourth speaker SP4 of the second speaker set 42.

[0046] The mixing unit 33 includes an 11th mixer MX11, a 12th mixer MX12, a 13th mixer MX13, and a 14th mixer MX14. The 11th mixer MX11 mixes the signal output from the 1st mixer MX1 ​​and the signal output from the 5th mixer MX5, and outputs the mixed signal to the 1st speaker SP1. The 12th mixer MX12 mixes the signal output from the 2nd mixer MX2 and the signal output from the 6th mixer MX6, and outputs the mixed signal to the 2nd speaker SP2. The 13th mixer MX13 mixes the signal output from the 3rd mixer MX3 and the signal output from the 7th mixer MX7, and outputs the mixed signal to the 3rd speaker SP3. The 14th mixer MX14 mixes the signal output from the 4th mixer MX4 and the signal output from the 8th mixer MX8, and outputs the mixed signal to the 4th speaker SP4.

[0047] The speaker device 40 includes a first speaker set 41 and a second speaker set 42. Figure 3 and Figure 4 As shown, in the vehicle 100, a first seat 90R and a second seat 90L are arranged side by side. The first seat 90R is arranged on the right side of the center of the vehicle 100. The first seat 90R has a headrest 91R, a seat back 92R, and a seat cushion 93R. The second seat 90L is arranged on the left side of the center of the vehicle 100. The second seat 90L has a headrest 91L, a seat back 92L, and a seat cushion 93L.

[0048] The first speaker set 41 is provided on the headrest 91R of the first seat 90R. The first speaker SP1 is provided on the left side of the headrest 91R. The second speaker SP2 is provided on the right side of the headrest 91R. The second speaker set 42 is provided on the headrest 91L of the second seat 90L. The third speaker SP3 is provided on the left side of the headrest 91L. The fourth speaker SP4 is provided on the right side of the headrest 91L.

[0049] The first interference sound is an interference sound output from the first speaker set 41. The second interference sound is an interference sound output from the second speaker set 42. The first call sound is a call sound output from the first speaker set 41. The second call sound is a call sound output from the second speaker set 42. In other words, the first speaker set 41 outputs the first interference sound and the first call sound. The second speaker set 42 outputs the second interference sound and the second call sound.

[0050] The first call tone is an example of the "first playback tone", and the second call tone is an example of the "second playback tone". The playback tone includes music playback tone, video content playback tone, broadcast tone, various notification tones, etc. In this embodiment, the call tone is used as an example for description.

[0051] The first zone ZN1 is a zone that includes the first speaker set 41 and includes the head of the passenger when the passenger sits in the first seat 90R. In other words, the first speaker set 41 is arranged in the first zone ZN1. The second zone ZN2 is a zone that includes the second speaker set 42 and includes the head of the passenger when the passenger sits in the second seat 90L. In other words, the second speaker set 42 is arranged in the second zone ZN2.

[0052] Next, refer to Figure 5 The design procedure of the first filter FL1 to the eighth filter FL8 will be described.

[0053] Figure 5 1 is an explanatory diagram for the speakers and virtual microphones arranged in the first zone ZN1 and the second zone ZN2. Figure 5 As shown, a first speaker set 41 is arranged in the first zone ZN1, and 10 virtual microphones M1 to M10 are arranged. Virtual microphones M1 to M5 are arranged near the first speaker SP1. The power output by virtual microphones M1, M2, M3, M4 and M5 is set to p1, p2, p3, p4 and p5 respectively. Virtual microphones M6 to M10 are arranged near the second speaker SP2. The power output by virtual microphones M6, M7, M8, M9 and M10 is set to p6, p7, p8, p9 and p10 respectively. 10 .

[0054] The second speaker set 42 is arranged in the second zone ZN2, and 10 virtual microphones M11 to M20 are arranged. The virtual microphones M11 to M15 are arranged near the third speaker SP3. The power output by the virtual microphones M11, M12, M13, M14 and M15 is respectively set to p 11 、p 12 、p 13 、p 14 and p 15 The virtual microphones M16 to M20 are arranged near the fourth speaker SP4. The power outputted by the virtual microphones M16, M17, M18, M19 and M20 is respectively represented by p 16 、p 17 、p 18 、p 19 and p 20 .

[0055] The first source signal SO1 is input to the first speaker SP1 via the first filter control circuit FC1. The first filter control circuit FC1 is a circuit including a first low pass filter LP1, a first filter FL1, a first high pass filter HP1, a first delay device DL1, a first amplifier AM1, a first mixer MX1, and an eleventh mixer MX11.

[0056] The first source signal SO1 is input to the second speaker SP2 via the second filter control circuit FC2. The second filter control circuit FC2 is a circuit including a first low pass filter LP1, a second filter FL2, a first high pass filter HP1, a first delay device DL1, a second amplifier AM2, a second mixer MX2, and a twelfth mixer MX12.

[0057] The first source signal SO1 is input to the third speaker SP3 via the third filter control circuit FC3. The third filter control circuit FC3 is a circuit including a first low pass filter LP1, a third filter FL3, a first high pass filter HP1, a first delay device DL1, a third amplifier AM3, a third mixer MX3, and a thirteenth mixer MX13.

[0058] The first source signal SO1 is input to the fourth speaker SP4 via the fourth filter control circuit FC4. The fourth filter control circuit FC4 is a circuit including a first low pass filter LP1, a fourth filter FL4, a first high pass filter HP1, a first delay device DL1, a fourth amplifier AM4, a fourth mixer MX4, and a fourteenth mixer MX14.

[0059] As mentioned above, in Figure 5 In the example shown, it is assumed that the first speaker set 41 and the second speaker set 42 have a total of four speakers, and 20 virtual microphones M1 to M20 are virtually arranged in the entire zone including the first zone ZN1 and the second zone ZN2.

[0060] Below, refer to Figure 3 to Figure 5 In the example shown, a partition filter for interference sound is studied. For example, in a right-hand drive car, the first seat 90R corresponds to the driver's seat, and the second seat 90L corresponds to the front passenger seat. In this case, the person sitting in the first seat 90R is the driver, and the person sitting in the second seat 90L is the passenger. As a premise of this embodiment, when the driver makes or receives a call, a hands-free call is made. In this case, the interference sound is output in a way that the passenger cannot easily hear the call sound.

[0061] The low-frequency interference sound based on the first low-frequency signal SL1 is output from any of the first speaker SP1 , the second speaker SP2 , the third speaker SP3 , and the fourth speaker SP4 .

[0062] The characteristic function representing the characteristics of the first filter group FG1 and the second filter group FG2 is defined as g jammer Here, the characteristic function g used for the interference sound is jammer Since the number of speakers is four, it can be represented by a matrix of four rows and one column as shown in the following formula (1).

[0063] g jammer =[g1 g2 g3 g4] T ···(1)

[0064] The target characteristic of the partition filter for interference sound must at least be such that the total volume of the first interference sound and the second interference sound audible in the second partition ZN2 is greater than the total volume of the first interference sound and the second interference sound audible in the first partition ZN1.

[0065] As the target characteristic of the partition filter for interference sound, the inventors proposed a target function d that satisfies the following conditions based on the results obtained through experiments, simulations, etc. jammer The objective function d for the interference sound jammer Since the number of virtual microphones is 20, it can be represented by a matrix of 20 rows and 1 column as shown in the following formula (2).

[0066] d jammer =[p1 p2…p 20 ] T ···(2)

[0067] The objective function d for the interference sound jammer The conditions that should be satisfied are the following conditions (a) and (b).

[0068] (a) In the virtual microphones M1 to M10, the sound is muted, that is, the power p1 to p2 outputted from the virtual microphones M1 to M10, respectively. 10 is 0.

[0069] (b) The third speaker SP3 and the fourth speaker SP4 provided in the headrest 91L of the front passenger seat output interference sounds in opposite phases, and the virtual microphones M11 to M20 output power p 11 ~p 20 .

[0070] The transfer function representing the transfer characteristics from the input of the first filter group FG1 and the second filter group FG2 to the output of the M virtual microphones M1 to M20 is represented by a transfer function matrix H having 20 rows and 4 columns. 20×4 express.

[0071] The characteristics of the first filter group FG1 and the characteristics of the second filter group FG2 are obtained by calculating the characteristic function g satisfying the following relationship (3): jammer The approximate solution of is calculated.

[0072] H 20×4 *g jammer =d jammer ···(3)

[0073] More specifically, the transfer function matrix H is a 20-row, 4-column matrix and is not regular, so the inverse matrix cannot be found. Therefore, as the characteristic function g jammer The least squares solution of the following equation (4) is obtained by using the approximate solution of .

[0074] g jammer =(H H H 20×4 +λI) －1 H H d jammer ···(4)

[0075] Here, H H is the transfer function matrix H 20×4 The adjoint matrix of H The eigenvalues ​​of , I is the identity matrix.

[0076] At this time, the high-frequency interference sound based on the first high-frequency signal SH1 is controlled to be output from the third speaker SP3 and the fourth speaker SP4, and not output from the first speaker SP1 and the second speaker SP2. More specifically, the gain of the first amplifier AM1 and the gain of the second amplifier AM2 are both set to zero.

[0077] As described above, the characteristics of the first filter group FG1 and the characteristics of the second filter group FG2 are expressed as characteristic functions g jammer . Characteristic function g jammer The setting is made such that the total volume of the first interfering sound and the second interfering sound audible in the second zone ZN2 is larger than the total volume of the first interfering sound and the second interfering sound audible in the first zone ZN1.

[0078] Next, refer to Figure 5 In the example shown, a partition filter for call sounds is studied. The call sounds are output from each speaker. In addition, in this case, Figure 5 The first filter control circuit FC1, the second filter control circuit FC2, the third filter control circuit FC3 and the fourth filter control circuit FC4 are respectively replaced by the fifth filter control circuit FC5, the sixth filter control circuit FC6, the seventh filter control circuit FC7 and the eighth filter control circuit FC8.

[0079] The fifth filter control circuit FC5 is a circuit including a second low-pass filter LP2, a fifth filter FL5, a second high-pass filter HP2, a second delay device DL2, a fifth amplifier AM5, a fifth mixer MX5, and an eleventh mixer MX11.

[0080] The sixth filter control circuit FC6 is a circuit including a second low-pass filter LP2, a sixth filter FL6, a second high-pass filter HP2, a second delay device DL2, a sixth amplifier AM6, a sixth mixer MX6, and a twelfth mixer MX12.

[0081] The seventh filter control circuit FC7 is a circuit including a second low-pass filter LP2, a seventh filter FL7, a second high-pass filter HP2, a second delay device DL2, a seventh amplifier AM7, a seventh mixer MX7, and a thirteenth mixer MX13.

[0082] The eighth filter control circuit FC8 is a circuit including a second low-pass filter LP2, an eighth filter FL8, a second high-pass filter HP2, a second delay device DL2, an eighth amplifier AM8, an eighth mixer MX8, and a fourteenth mixer MX14.

[0083] The low-frequency call sound based on the second low-frequency signal SL2 is output from any of the first speaker SP1 , the second speaker SP2 , the third speaker SP3 , and the fourth speaker SP4 .

[0084] The characteristic function representing the characteristics of each filter in the first filter group FG1 and the characteristics of each filter in the second filter group FG2 is represented by g. Here, the characteristic function g for the call tone is a matrix of 4 rows and 1 column as shown in the following formula (5) because the number of speakers is 4.

[0085] g voice =[g1 g2 g3 g4] T ···(5)

[0086] The target characteristic of the partition filter for call sounds must at least be a characteristic that makes the total volume of the first call sound and the second call sound audible in the first partition ZN1 greater than the total volume of the first call sound and the second call sound audible in the second partition ZN2.

[0087] As the target characteristic of the partition filter for the call tone, the inventors proposed a target function d that satisfies the following conditions based on the results obtained through experiments, simulations, etc. voice The objective function d for the call tone voice Since the number of virtual microphones is 20, it can be represented by a matrix of 20 rows and 1 column as shown in the following formula (6).

[0088] d voice =[p1 p2…p 20 ] T ···(6)

[0089] Objective function d for call tone voice The conditions that should be satisfied are the following conditions (c) and (d).

[0090] (c) In the virtual microphones M1 to M5 and M11 to M20, the sound is muted, that is, the power p1 to p5 and p20 are outputted from the virtual microphones M1 to M5 and M11 to M20, respectively. 11 ~p 20 is 0.

[0091] (d) The second speaker SP2 provided on the headrest 91R of the driver's seat outputs the call sound, and the virtual microphones M6 to M10 output the electric powers p6 to p7. 10 .

[0092] The transfer function representing the transfer characteristics from the input of the third filter group FG3 and the fourth filter group FG4 to the output of the M virtual microphones M1 to M20 is represented by a transfer function matrix H having 20 rows and 4 columns. 20×4 express.

[0093] The characteristics of the third filter group FG3 and the fourth filter group FG4 are obtained by calculating the characteristic function g satisfying the following relationship (7): voice The approximate solution of is calculated.

[0094] H 20×4 *g voice =d voice ···(7)

[0095] As the characteristic function g voice The approximate solution of is used to obtain the least squares solution of the following equation (8).

[0096] g voice =(H H H 20×4 +λI) －1 H H d voice ···(8)

[0097] At this time, the high-frequency call sound based on the second high-frequency signal SH2 is controlled to be output from the first speaker SP1 , the second speaker SP2 , the third speaker SP3 , and the fourth speaker SP4 .

[0098] As described above, the characteristics of the third filter group FG3 and the fourth filter group FG4 are expressed as characteristic functions g voice. Characteristic function g voice The setting is made such that the total volume of the first call sound and the second call sound audible in the first zone ZN1 is larger than the total volume of the first call sound and the second call sound audible in the second zone ZN2.

[0099] A2: Summary of the first embodiment

[0100] As described above, the sound processing device 30 according to the first embodiment includes the first filter group FG1 and the second filter group FG2. The first low-frequency signal SL1 is input to the first filter group FG1. The first filter group FG1 includes the first filter FL1 and the second filter FL2. The first filter FL1 and the second filter FL2 control the first interfering sound output from the first speaker set 41 arranged in the first zone ZN1. The first speaker set 41 includes the first speaker SP1 and the second speaker SP2.

[0101] The first low-frequency signal SL1 is input to the second filter group FG2. The second filter group FG2 includes a third filter FL3 and a fourth filter FL4. The third filter FL3 and the fourth filter FL4 control the second interference sound output from the second speaker set 42 arranged in the second zone ZN2 close to the first zone ZN1. The second speaker set 42 includes a third speaker SP3 and a fourth speaker SP4.

[0102] The characteristics of the first filter group FG1 and the characteristics of the second filter group FG2 are set so that the total volume of the first interference sound and the volume of the second interference sound audible in the second zone ZN2 is greater than the total volume of the first interference sound and the volume of the second interference sound audible in the first zone ZN1.

[0103] According to this method, the interference sound audible in the first zone ZN1 can be reduced by the first filter group FG1 and the second filter group FG2. Therefore, the driver's discomfort can be suppressed. In addition, the interference sound is not easily heard in the first zone ZN1, so the driver can reduce the volume of the call sound.

[0104] In addition, the sound processing device 30 according to the first embodiment further includes a third filter group FG3 and a fourth filter group FG4. The second low-frequency signal SL2 is input to the third filter group FG3. The third filter group FG3 includes a fifth filter FL5 and a sixth filter FL6. The fifth filter FL5 and the sixth filter FL6 control the first call sound output from the first speaker set 41.

[0105] The second low frequency signal SL2 is input to the fourth filter group FG4. The fourth filter group FG4 includes a seventh filter FL7 and an eighth filter FL8. The seventh filter FL7 and the eighth filter FL8 control the second call sound output from the second speaker set 42.

[0106] The characteristics of the third filter group FG3 and the characteristics of the fourth filter group FG4 are set so that the total volume of the first call sound and the volume of the second call sound audible in the first zone ZN1 is greater than the total volume of the first call sound and the volume of the second call sound audible in the second zone ZN2.

[0107] According to this method, the conversation sound audible in the second partition ZN2 can be reduced by the third filter group FG3 and the fourth filter group FG4. Therefore, the discomfort of the fellow passengers can be suppressed. In addition, the conversation sound is not easy to be heard in the second partition ZN2, so the volume of the interference sound can be reduced. In particular, in order to obtain the effect of the interference sound in the frequency band less than 500 Hz, it is necessary to increase the volume of the interference sound, but according to this method, the conversation sound is also partitioned, so the effect of the interference sound in the frequency band less than 500 Hz is supplemented.

[0108] In the sound processing device 30 according to the first embodiment, it is assumed that the first speaker set 41 and the second speaker set 42 have a total of four speakers, and 20 virtual microphones M1 to M20 are virtually arranged in the entire zone including the first zone ZN1 and the second zone ZN2. The characteristics of the first filter group FG1 and the characteristics of the second filter group FG2 are obtained by calculating the transfer function matrix H 20×4 , characteristic function g jammer 、Objective function d jammer Satisfy H 20×4 *g jammer =d jammer The characteristic function g of the relationship jammer The approximate solution of is calculated.

[0109] Transfer function matrix H 20×4 The transfer characteristics from the input of the first filter group FG1 and the second filter group FG2 to the output of the 20 virtual microphones M1 to M20 are represented by a matrix of 20 rows and 4 columns. jammer It is represented by a 4-row 1-column matrix, each component of which represents the characteristics of the first filter FL1 and the second filter FL2 in the first filter group FG1 and the characteristics of the third filter FL3 and the fourth filter FL4 in the second filter group FG2. jammerRepresented by a 20-row, 1-column matrix, each component of the 20-row, 1-column matrix represents a target value of power corresponding to the first interference sound outputted from the 20 virtual microphones M1 to M20 and a target value of power corresponding to the second interference sound outputted from the 20 virtual microphones M1 to M20.

[0110] According to this aspect, it is possible to more easily design the first filter group FG1 and the second filter group FG2 so as to reduce the interfering sound audible in the first zone ZN1.

[0111] In the sound processing device 30 according to the first embodiment, it is assumed that the first speaker set 41 and the second speaker set 42 have a total of four speakers, and 20 virtual microphones M1 to M20 are virtually arranged in the entire zone including the first zone ZN1 and the second zone ZN2. The characteristics of the third filter group FG3 and the characteristics of the fourth filter group FG4 are obtained by calculating the transfer function matrix H 20×4 , characteristic function g voice 、Objective function d voice Satisfy H 20×4 *g voice =d voice The characteristic function g of the relationship voice The approximate solution of is calculated.

[0112] Transfer function matrix H 20×4 The transfer characteristics from the input of the third filter group FG3 and the fourth filter group FG4 to the output of the 20 virtual microphones M1 to M20 are represented by a matrix of 20 rows and 4 columns. jammer It is represented by a matrix of 4 rows and 1 column, and each component of the matrix of 4 rows and 1 column represents the characteristics of the fifth filter FL5 and the sixth filter FL6 in the third filter group FG3 and the characteristics of the seventh filter FL7 and the eighth filter FL8 in the fourth filter group FG4. jammer It is represented by a matrix of 20 rows and 1 column, and each component of the matrix represents the target value of power corresponding to the first call sound outputted from the 20 virtual microphones M1 to M20 and the target value of power corresponding to the second call sound outputted from the 20 virtual microphones M1 to M20.

[0113] According to this aspect, it is possible to more easily design the third filter group FG3 and the fourth filter group FG4 that reduce the conversation sound audible in the second zone ZN2.

[0114] In the sound processing device 30 according to the first embodiment, it is assumed that a first low-pass filter LP1 is provided in the front stage of the first filter group FG1 and the second filter group FG2. The first low-pass filter LP1 outputs a first low-frequency signal SL1 by cutting off the high-frequency component of the first source signal SO1 which is the source signal of the first interfering sound and the second interfering sound.

[0115] The partition filter is effective in the lower frequency region, so there is no problem even if the frequency region processed by the partition filter is limited to the lower frequency region. The amount of calculation of the partition filter can be reduced by limiting the frequency region processed by the partition filter to the region below the specified frequency. Therefore, according to this method, a higher precision calculation can be performed without significantly increasing the processing load of the processor.

[0116] In the sound processing device 30 according to the first embodiment, a second low-pass filter LP2 is provided in the front stage of the third filter group FG3 and the fourth filter group FG4. The second low-pass filter LP2 outputs a second low-frequency signal SL2 by cutting off the high-frequency component of the second source signal SO2 which is the source signal of the first and second call sounds.

[0117] The partition filter is effective in a relatively low frequency region, so there is no problem even if the frequency region processed by the partition filter is limited to a relatively low frequency region. The amount of computation of the partition filter can be reduced by limiting the frequency region processed by the partition filter to a region below a specified frequency. Therefore, according to this method, a more accurate computation can be performed without significantly increasing the processing load of the processor.

[0118] In the sound processing device 30 according to the first embodiment, a first low-pass filter LP1 is provided before the first filter group FG1 and the second filter group FG2. The first low-pass filter LP1 outputs a first low-frequency signal SL1 by cutting off high-frequency components of a first source signal SO1 which is a source signal of the first and second interfering sounds.

[0119] The first source signal SO1 is separated into a first low-frequency signal SL1 and a first high-frequency signal SH1 by passing through a first low-pass filter LP1 and a first high-pass filter HP1 provided in parallel with the first low-pass filter LP1. The signal of the first low-frequency signal SL1 that has passed through the first filter group FG1 is synthesized with a signal of the first high-frequency signal SH1 whose amplitude is adjusted by the first amplifier group AG1 provided at the rear stage of the first high-pass filter HP1, and then input to the first speaker set 41. The signal of the first low-frequency signal SL1 that has passed through the second filter group FG2 is synthesized with a signal of the first high-frequency signal SH1 whose amplitude is adjusted by the second amplifier group AG2 provided at the rear stage of the first high-pass filter HP1, and then input to the second speaker set 42.

[0120] The second source signal SO2 is separated into a second low-frequency signal SL2 and a second high-frequency signal SH2 by passing through a second low-pass filter LP2 and a second high-pass filter HP2 provided in parallel with the second low-pass filter LP2. The signal of the second low-frequency signal SL2 that has passed through the third filter group FG3 is synthesized with a signal of the second high-frequency signal SH2 whose amplitude is adjusted by the third amplifier group AG3 provided at the rear stage of the second high-pass filter HP2, and then input to the first speaker set 41. The signal of the second low-frequency signal SL2 that has passed through the fourth filter group FG4 is synthesized with a signal of the second high-frequency signal SH2 whose amplitude is adjusted by the fourth amplifier group AG4 provided at the rear stage of the second high-pass filter HP2, and then input to the second speaker set 42.

[0121] The cutoff frequency of the first low-pass filter LP1 , the cutoff frequency of the first high-pass filter HP1 , the cutoff frequency of the second low-pass filter LP2 , and the cutoff frequency of the second high-pass filter HP2 are substantially equal to each other.

[0122] According to this embodiment, the frequency bands processed by the first filter group FG1, the second filter group FG2, the third filter group FG3 and the fourth filter group FG4 are consistent, so the design of the first filter group FG1, the second filter group FG2, the third filter group FG3 and the fourth filter group FG4 becomes easier.

[0123] In the sound processing device 30 according to the first embodiment, the first filter group FG1 and the second filter group FG2 are formed of FIR filters.

[0124] According to this aspect, the amplitude and phase of the first interfering sound generated from the first speaker set 41 and the amplitude and phase of the second interfering sound generated from the second speaker set 42 can be precisely controlled. As a result, the volume of the interfering sound can be reduced, and the discomfort of the driver and fellow passengers can be suppressed.

[0125] Furthermore, in the sound processing device 30 according to the first embodiment, the third filter group FG3 and the fourth filter group FG4 are formed of FIR filters.

[0126] According to this aspect, the amplitude and phase of the first call sound generated from the first speaker set 41 and the amplitude and phase of the second call sound generated from the second speaker set 42 can be precisely controlled. As a result, the volume of the interfering sound can be reduced, and the discomfort of the driver and fellow passengers can be suppressed.

[0127] The in-vehicle audio system 1 according to the first embodiment includes a first speaker set 41, a second speaker set 42, and a sound processing device 30. The first speaker set 41 is disposed in the first zone ZN1. The second speaker set 42 is disposed in the second zone ZN2 adjacent to the first zone ZN1.

[0128] The sound processing device 30 includes a second filter group FG2, a third filter group FG3, and a fourth filter group FG4. The first filter group FG1 controls the first interference sound output from the first speaker set 41. The second filter group FG2 controls the second interference sound output from the second speaker set 42. The third filter group FG3 controls the first call sound output from the first speaker set 41. The fourth filter group FG4 controls the second call sound output from the second speaker set 42.

[0129] The characteristics of the first filter group FG1 and the characteristics of the second filter group FG2 are set so that the total volume of the first interference sound and the second interference sound audible in the second zone ZN2 is greater than the total volume of the first interference sound and the second interference sound audible in the first zone ZN1. The characteristics of the third filter group FG3 and the characteristics of the fourth filter group FG4 are set so that the total volume of the first call sound and the second call sound audible in the first zone ZN1 is greater than the total volume of the first call sound and the second call sound audible in the second zone ZN2.

[0130] According to this method, the conversation sound audible in the second zone ZN2 can be reduced by the first filter group FG1 and the second filter group FG2. Therefore, the volume of the interference sound can be reduced in the second zone ZN2. In addition, the interference sound audible in the first zone ZN1 can be reduced by the third filter group FG3 and the fourth filter group FG4. Therefore, the privacy of the driver during the conversation can be easily ensured, and the discomfort of the driver and the passengers can be suppressed.

[0131] In the vehicle audio system 1 according to the first embodiment, the first zone ZN1 corresponds to the first seat 90R, which is the driver's seat of the vehicle 100, and the second zone ZN2 corresponds to the second seat 90L, which is the passenger seat of the vehicle 100. The first speaker set 41 is a headrest speaker set provided on the headrest 91R of the first seat 90R. The second speaker set 42 is a headrest speaker set provided on the headrest 91L of the second seat 90L.

[0132] According to this aspect, the call sound and the interference sound are output using the speaker sets located close to the driver's head and the passenger's head, respectively, so that a more significant partitioning effect is obtained.

[0133] B: Deformation

[0134] The present invention is not limited to the above-mentioned embodiments, and various modifications can be adopted within the scope of the present invention. The following examples illustrate specific modified modes. In addition, two or more modes arbitrarily selected from the following examples can be appropriately combined within the scope that does not contradict each other. In addition, in the following examples, for the elements having the same effects and functions as the above-mentioned embodiments, the reference numerals used in the above description are used and the respective detailed descriptions are appropriately omitted.

[0135] B1: First variant

[0136] In the first embodiment, it is assumed that the first speaker set 41 and the second speaker set 42 have a total of 4 speakers, and 20 virtual microphones are virtually configured in the entire partition including the first partition ZN1 and the second partition ZN2. However, the number of virtual microphones is not limited to 20, and the number of virtual microphones can be any number. It can be imagined that the more virtual microphones there are, the more robust the designed partition filter is, and the easier it is to obtain the effect of the partition filter for unexpected sound signals. However, the number of virtual microphones is preferably a multiple of 4, which is the number of speakers. Below, the number of virtual microphones is set to M and the description continues.

[0137] Figure 6 FIG. 2 is an explanatory diagram of the speakers and virtual microphones arranged in the first zone ZN1 and the second zone ZN2 according to the first modification example. Figure 6 As shown, the first speaker set 41 is arranged in the first zone ZN1, and M / 2 virtual microphones are arranged. The power output from the M / 2 virtual microphones is respectively set to p1, p2, ..., p M / 4 、p M / 4+1 、p M / 4+2 ,…,p M / 2 The second speaker set 42 is arranged in the second zone ZN2, and M / 2 virtual microphones are arranged. The power output by the M / 2 virtual microphones is respectively set to p M / 2+1 、p M / 2+2 ,…,p 3M / 4 、p 3M / 4+1 、p 3M / 4+2 ,…,p M .

[0138] As mentioned above, in Figure 6 In the example shown, it is assumed that the first speaker set 41 and the second speaker set 42 have a total of four speakers, and M virtual microphones are virtually arranged in the entire zone including the first zone ZN1 and the second zone ZN2.

[0139] In addition, the number of speakers is not limited to 4, and the number of speakers can be extended to L. When the number of speakers is L and the number of virtual microphones is M, the characteristics of the first filter group FG1 and the characteristics of the second filter group FG2 are obtained by calculating the transfer function matrix H M×L , characteristic function g jammer And the objective function d jammer satisfy

[0140] H M×L *g jammer =d jammer The characteristic function g of the relationship (9) jammer The approximate solution of is calculated.

[0141] Transfer function matrix H M×L The transfer characteristic from the input of the first filter group FG1 and the second filter group FG2 to the output of the M virtual microphones is represented by a matrix of M rows and L columns. jammer It is represented by a matrix of L rows and 1 column, and each component of the matrix of L rows and 1 column represents the characteristics of the first filter FL1 and the second filter FL2 in the first filter group FG1 and the characteristics of the third filter FL3 and the fourth filter FL4 in the second filter group FG2. jammer It is represented by a matrix of M rows and one column, and each component of the matrix represents the target value of power corresponding to the first interference sound outputted from each of the M virtual microphones and the target value of power corresponding to the second interference sound outputted from each of the M virtual microphones.

[0142] In addition, the characteristics of the third filter group FG3 and the fourth filter group FG4 are obtained by calculating the transfer function matrix H M×L , characteristic function g voice And the objective function d voice satisfy

[0143] H M×L *g voice =d voice The characteristic function g of the relationship (10) voice The approximate solution of is calculated.

[0144] Transfer function matrix H M×L The transfer characteristics from the input of the third filter group FG3 and the fourth filter group FG4 to the output of the M virtual microphones are represented by a matrix of M rows and L columns. voiceIt is represented by a matrix of L rows and 1 column, and each component of the matrix of L rows and 1 column represents the characteristics of the fifth filter FL5 and the sixth filter FL6 in the third filter group FG3 and the characteristics of the seventh filter FL7 and the eighth filter FL8 in the fourth filter group FG4. Objective function d voice It is represented by a matrix of M rows and one column, and each component of the matrix represents the target value of power corresponding to the first call sound outputted from each of the M virtual microphones and the target value of power corresponding to the second call sound outputted from each of the M virtual microphones.

[0145] B2: Second modification

[0146] Figure 7 1 is a front view showing an example of the arrangement of the first speaker set 41 and the second speaker set 42 according to the second modification. In the first embodiment, the first speaker set 41 is provided on the headrest 91R of the first seat 90R, which is the driver's seat, but it may also be provided as follows. Figure 7 As shown, the first speaker set 41 is provided on the seat back 92R of the first seat 90R. In the first embodiment, the second speaker set 42 is provided on the headrest 91L of the second seat 90L, which is the passenger seat, but it may also be provided as Figure 7 The speaker set 41 is provided in the seat back 92L of the second seat 90L. In this modification, the first speaker set 41 is arranged in the first zone ZN1A, and the second speaker set 42 is arranged in the second zone ZN2A.

[0147] As described above, in the in-vehicle audio system 1 according to the second modified example, the first zone ZN1A corresponds to the first seat 90R of the vehicle 100, and the second zone ZN2A corresponds to the second seat 90L of the vehicle 100. The first speaker set 41 is a seat back speaker set provided on the seat back 92R of the first seat 90R. The second speaker set 42 is a seat back speaker set provided on the seat back 92L of the second seat 90L.

[0148] According to this aspect, the call sound and the interference sound are outputted by using the speaker sets located close to the driver's head and the passenger's head, respectively, so that a more significant partitioning effect is obtained.

[0149] B3: The third variant

[0150] Figure 8 1 is a front view showing an example of the arrangement of the first speaker set 41 and the second speaker set 42 according to the third modification. In the first embodiment, the first speaker set 41 is provided on the headrest 91R of the first seat, but it may also be provided as follows. Figure 8As shown, the first speaker set 41 is provided in a position above the first seat 90R in the ceiling 101 of the vehicle 100. In the first embodiment, the second speaker set 42 is provided in the headrest 91L of the second seat 90L, but it may also be provided in a Figure 8 As shown, it is provided at a location above the second seat 90L in the ceiling 101. In this modification, the first speaker set 41 is arranged in the first zone ZN1B, and the second speaker set 42 is arranged in the second zone ZN2B.

[0151] As described above, in the vehicle audio system 1 according to the third modified example, the first zone ZN1B corresponds to the first seat 90R of the vehicle 100, and the second zone ZN2B corresponds to the second seat 90L of the vehicle 100. The first speaker set 41 is a ceiling speaker set provided in a portion above the first seat 90R in the ceiling 101 of the vehicle 100. The second speaker set 42 is a ceiling speaker set provided in a portion above the second seat 90L in the ceiling 101.

[0152] According to this aspect, the call sound and the interference sound are outputted by using the speaker sets located close to the driver's head and the passenger's head, respectively, so that a more significant partitioning effect is obtained.

[0153] B4: 4th variant

[0154] In the first embodiment, the cutoff frequency of the first low-pass filter LP1 is set to 500 Hz, but the cutoff frequency is not limited to 500 Hz. The cutoff frequency may be a frequency within a range of 500 Hz plus or minus K% (for example, 20%).

[0155] B5: The fifth variant

[0156] The first filter FL1 to the eighth filter FL8 are not limited to FIR filters, and other digital filters such as IIR (Infinite Impulse Response) filters can be applied to the first filter FL1 to the eighth filter FL8.

[0157] B6: Sixth variant

[0158] The in-car audio system 1 according to the first embodiment is mounted on a vehicle such as an automobile, but the in-car audio system 1 can also be applied to the fields of home audio and professional audio.

[0159] B7: The seventh variant

[0160] In the first embodiment, the second modification, and the third modification, the first speaker set 41 and the second speaker set 42 are described as being disposed at locations, but the first speaker set 41 and the second speaker set 42 are not limited to being disposed at the headrest, the seat back, and the ceiling. The first speaker set 41 can be disposed at any location in the vehicle 100 as long as the driver's head is included in the first zone ZN1. The second speaker set 42 can be disposed at any location in the vehicle 100 as long as the passenger's head is included in the second zone ZN2.

[0161] C: Appendix

[0162] According to the above-exemplified aspects, for example, the following configurations can be understood.

[0163] A sound processing device according to one embodiment of the present invention (embodiment 1) comprises: a first filter group, to which a first sound signal is input, and includes one or more filters for controlling a first interfering sound output from a first speaker set including one or more speakers arranged in a first partition; and a second filter group, to which the first sound signal is input, and includes one or more filters for controlling a second interfering sound output from a second speaker set including one or more speakers arranged in a second partition close to the first partition, wherein the characteristics of the first filter group and the characteristics of the second filter group are set so that the total volume of the first interfering sound and the volume of the second interfering sound audible in the second partition is greater than the total volume of the first interfering sound and the volume of the second interfering sound audible in the first partition.

[0164] According to this method, the interference sound audible in the first partition can be reduced by the first filter group and the second filter group. Therefore, the driver's discomfort can be suppressed. In addition, the interference sound is not easily heard in the first partition, so the driver can reduce the volume of the call sound.

[0165] The sound processing device involved in one embodiment (embodiment 2) of the present invention further includes: a third filter group, which is input with the second sound signal and includes one or more filters for controlling the first broadcast sound output from the first speaker set; and a fourth filter group, which is input with the second sound signal and includes one or more filters for controlling the second broadcast sound output from the second speaker set, and the characteristics of the third filter group and the characteristics of the fourth filter group are set so that the total volume of the first broadcast sound and the volume of the second broadcast sound that can be heard in the first partition is greater than the total volume of the first broadcast sound and the volume of the second broadcast sound that can be heard in the second partition.

[0166] According to this method, the playback sound audible in the second partition can be reduced by the third filter group and the fourth filter group. Therefore, the discomfort of the fellow passengers can be suppressed. In addition, the playback sound is not easily heard in the second partition, so the volume of the interference sound can be reduced. In particular, in order to obtain the effect of the interference sound in the frequency band less than 500 Hz, it is necessary to increase the volume of the interference sound, but according to this method, the playback sound is also partitioned, so the effect of the interference sound in the frequency band less than 500 Hz is supplemented.

[0167] A method for generating a bass-range emphasis signal according to one embodiment (embodiment 3) of the present invention, wherein the first speaker set and the second speaker set have a total of L speakers, M virtual microphones are virtually arranged in the entire partition including the first partition and the second partition, and the characteristics of the first filter group and the characteristics of the second filter group are obtained by performing a characteristic function g jammer The transfer function matrix H is represented by a matrix of M rows and L columns and represents the transfer characteristics from the input of the first filter group and the second filter group to the output of the M virtual microphones. M×L The characteristic function g is represented by a matrix of L rows and 1 column, and each component of the matrix of L rows and 1 column represents the characteristics of each filter in the first filter group and the characteristics of each filter in the second filter group. jammer , and a target function d represented by a matrix of M rows and 1 column, wherein each component of the matrix of M rows and 1 column represents a target value of the power corresponding to the first interference sound outputted from the M virtual microphones and a target value of the power corresponding to the second interference sound outputted from the M virtual microphones. jammer Satisfy H M×L *g jammer =d jammer relationship.

[0168] According to this aspect, it is possible to more easily design the first filter group and the second filter group that reduce the interfering sound audible in the first section.

[0169] A method for generating a bass-range emphasis signal according to one embodiment of the present invention (embodiment 4) is provided, wherein the first speaker set and the second speaker set have a total of L speakers, M virtual microphones are virtually arranged in the entire partition including the first partition and the second partition, and the characteristics of the third filter group and the characteristics of the fourth filter group are obtained by performing a characteristic function g voice The transfer function matrix H represented by a matrix of M rows and L columns and representing the transfer characteristics from the input of the third filter group and the fourth filter group to the output of the M virtual microphones is obtained by calculating the approximate solution ofM×L The characteristic function g is represented by a matrix of L rows and 1 column, and each component of the matrix of L rows and 1 column represents the characteristics of each filter in the third filter group and the characteristics of each filter in the fourth filter group. voice , and a target function d represented by a matrix of M rows and 1 column, wherein each component of the matrix represents a target value of power corresponding to the first broadcast sound outputted from the M virtual microphones and a target value of power corresponding to the second broadcast sound outputted from the M virtual microphones. voice Satisfy H M×L *g voice =d voice relationship.

[0170] According to this aspect, it is possible to more easily design the third filter group and the fourth filter group that reduce the broadcast sound audible in the second section.

[0171] Regarding a sound processing device involved in one embodiment (embodiment 5) of the present invention, a first low-pass filter is set in the front stage of the first filter group and the second filter group, and the first low-pass filter outputs a first low-frequency signal by cutting off the high-frequency component of the first source signal which is the source signal of the first interference sound and the second interference sound.

[0172] The partition filter is effective in the lower frequency region, so there is no problem even if the frequency region processed by the partition filter is limited to the lower frequency region. By limiting the frequency region processed by the partition filter to the region below the specified frequency, the amount of calculation of the partition filter can be reduced. Therefore, according to this method, a higher precision calculation can be performed without significantly increasing the processing load of the processor.

[0173] Regarding a sound processing device involved in one mode (mode 6) of the present invention, a second low-pass filter is set in the front stage of the third filter group and the fourth filter group, and the second low-pass filter outputs a second low-frequency signal by cutting off the high-frequency component of the source signal of the first broadcast sound and the second broadcast sound, that is, the second source signal.

[0174] The partition filter is effective in a relatively low frequency region, so there is no problem even if the frequency region processed by the partition filter is limited to a relatively low frequency region. By limiting the frequency region processed by the partition filter to a region below a specified frequency, the amount of computation of the partition filter can be reduced. Therefore, according to this method, a more accurate computation can be performed without significantly increasing the processing load of the processor.

[0175] A sound processing device according to one embodiment (embodiment 7) of the present invention includes a first low-pass filter provided at a stage preceding the first filter group and the second filter group, the first low-pass filter outputting a first low-frequency signal as the first sound signal by cutting off a high-frequency component of a first source signal which is a source signal of the first interfering sound and the second interfering sound, the first source signal being separated into the first low-frequency signal and the first high-frequency signal by the first low-pass filter and a first high-pass filter provided in parallel with the first low-pass filter, the signal of the first low-frequency signal after passing through the first filter group being synthesized with a signal of which the amplitude of the first high-frequency signal is adjusted by a first amplifier group provided at a stage following the first high-pass filter, and then being input to the first speaker set, the signal of the first low-frequency signal after passing through the second filter group being synthesized with a signal of which the amplitude of the first high-frequency signal is adjusted by a second amplifier group provided at a stage following the first high-pass filter, and then being input to the first speaker set. The second source signal is input to the second speaker set after being synthesized with a signal of the amplitude of the second signal by the third amplifier group provided at the rear stage of the second high pass filter, the second source signal is separated into the second low-frequency signal and the second high-frequency signal by the second low-pass filter and the second high-pass filter, the signal of the second low-frequency signal after passing through the third filter group is input to the first speaker set after being synthesized with a signal of the amplitude of the second high-frequency signal by the third amplifier group provided at the rear stage of the second high pass filter, and the signal of the second low-frequency signal after passing through the fourth filter group is input to the second speaker set after being synthesized with a signal of the amplitude of the second high-frequency signal by the fourth amplifier group provided at the rear stage of the second high pass filter, and the cut-off frequency of the first low-pass filter, the cut-off frequency of the first high pass filter, the cut-off frequency of the second low-pass filter, and the cut-off frequency of the second high pass filter are substantially equal to each other.

[0176] According to this aspect, the frequency bands processed by the first filter group, the second filter group, the third filter group, and the fourth filter group are identical, so the design of the first filter group, the second filter group, the third filter group, and the fourth filter group becomes easier.

[0177] In the sound processing device according to one aspect (aspect 8) of the present invention, the first filter group and the second filter group are formed of FIR filters.

[0178] According to this aspect, the amplitude and phase of the first interfering sound generated from the first speaker set and the amplitude and phase of the second interfering sound generated from the second speaker set can be finely controlled. As a result, the volume of the interfering sound can be reduced, and the discomfort of the driver and fellow passengers can be suppressed.

[0179] In the sound processing device according to one aspect (aspect 9) of the present invention, the third filter group and the fourth filter group are formed of FIR filters.

[0180] According to this aspect, the amplitude and phase of the first sound emitted from the first speaker set and the amplitude and phase of the second sound emitted from the second speaker set can be finely controlled. As a result, the volume of the interfering sound can be reduced, and the discomfort of the driver and fellow passengers can be suppressed.

[0181] An in-vehicle audio system according to one embodiment of the present invention (embodiment 10) comprises: a first speaker set arranged in a first partition; a second speaker set arranged in a second partition close to the first partition; and a sound processing device comprising a first filter group for controlling a first interference sound output from the first speaker set, a second filter group for controlling a second interference sound output from the second speaker set, a third filter group for controlling a first broadcast sound output from the first speaker set, and a fourth filter group for controlling a second broadcast sound output from the second speaker set, wherein the first filter group The characteristics of the first filter group and the characteristics of the second filter group are set so that the total volume of the first interference sound and the volume of the second interference sound audible in the second partition is greater than the total volume of the first interference sound and the volume of the second interference sound audible in the first partition, and the characteristics of the third filter group and the characteristics of the fourth filter group are set so that the total volume of the first broadcast sound and the volume of the second broadcast sound audible in the first partition is greater than the total volume of the first broadcast sound and the volume of the second broadcast sound audible in the second partition.

[0182] According to this method, the playback sound audible in the second partition can be reduced by the first filter group and the second filter group. Therefore, the volume of the interfering sound in the second partition can be reduced. In addition, the interfering sound audible in the first partition can be reduced by the third filter group and the fourth filter group. Therefore, the privacy of the driver during the call can be easily ensured, and the discomfort of the driver and the passengers can be suppressed.

[0183] Regarding a vehicle audio system involved in one embodiment (embodiment 11) of the present invention, wherein the first partition corresponds to a driver's seat of a vehicle, the second partition corresponds to a front passenger seat of the vehicle, the first speaker set is a headrest speaker set arranged on the headrest of the driver's seat, and the second speaker set is a headrest speaker set arranged on the headrest of the front passenger seat.

[0184] According to this aspect, the broadcast sound and the disturbance sound are outputted using the speaker sets located close to the driver's head and the passenger's head, respectively, so that a more significant partitioning effect is obtained.

[0185] Regarding a vehicle audio system involved in one embodiment (embodiment 12) of the present invention, wherein the first partition corresponds to a driver's seat of a vehicle, the second partition corresponds to a front passenger seat of the vehicle, the first speaker set is a seat back speaker set arranged on the seat back of the driver's seat, and the second speaker set is a seat back speaker set arranged on the seat back of the front passenger seat.

[0186] According to this aspect, the broadcast sound and the disturbance sound are outputted using the speaker sets located close to the driver's head and the passenger's head, respectively, so that a more significant partitioning effect is obtained.

[0187] Regarding a vehicle audio system involved in one embodiment (embodiment 13) of the present invention, wherein the first partition corresponds to a driver's seat of a vehicle, the second partition corresponds to a front passenger seat of the vehicle, the first speaker set is a ceiling speaker set arranged in a portion of the ceiling of the vehicle above the driver's seat, and the second speaker set is a ceiling speaker set arranged in a portion of the ceiling above the front passenger seat.

[0188] According to this aspect, the broadcast sound and the disturbance sound are outputted using the speaker sets located close to the driver's head and the passenger's head, respectively, so that a more significant partitioning effect is obtained.

[0189] Description of the label

[0190] 1…In-car audio system, 30…Sound processing device, 41…1st speaker set, 42…2nd speaker set, 90R…1st seat (driver's seat), 90L…2nd seat (passenger seat), 91L, 91R…Headrest, 92L, 92R…Seat back, 100…Vehicle, 101…Ceiling, AG1…1st amplifier set, AG2…2nd amplifier set, AG3…3rd amplifier set, AG4…4th amplifier set, FG1…1st filter set, FG2…2nd filter set, FG3…3rd filter set Filter group, FG4…4th filter group, HP1…1st high-pass filter, HP2…2nd high-pass filter, LP1…1st low-pass filter, LP2…2nd low-pass filter, M1~M20…virtual microphone, SH1…1st high-frequency signal, SH2…2nd high-frequency signal, SL1…1st low-frequency signal, SL2…2nd low-frequency signal, SO1…1st source signal, SO2…2nd source signal, ZN1, ZN1A, ZN1B…1st partition, ZN2, ZN2A, ZN2B…2nd partition.

Claims

1. A sound processing device, comprising: a first filter group to which the first sound signal is input, and includes one or more filters for controlling a first interfering sound output from a first speaker set including one or more speakers arranged in a first zone; and a second filter group, to which the first sound signal is input, including one or more filters for controlling a second interfering sound output from a second speaker set including one or more speakers arranged in a second partition close to the first partition, The characteristics of the first filter group and the characteristics of the second filter group are set so that the total volume of the first interference sound and the volume of the second interference sound audible in the second partition is greater than the total volume of the first interference sound and the volume of the second interference sound audible in the first partition.

2. The sound processing device according to claim 1, wherein: Also features: a third filter group to which the second sound signal is input, and includes one or more filters for controlling the first playback sound output from the first speaker set; and a fourth filter group to which the second sound signal is input, and includes one or more filters for controlling the second broadcast sound output from the second speaker set, The characteristics of the third filter group and the characteristics of the fourth filter group are set so that the total volume of the first broadcast sound and the volume of the second broadcast sound audible in the first partition is greater than the total volume of the first broadcast sound and the volume of the second broadcast sound audible in the second partition.

3. The sound processing device according to claim 1, wherein: The first speaker set and the second speaker set have a total of L speakers. Assume that M virtual microphones are virtually arranged in the entire partition including the first partition and the second partition, The characteristics of the first filter group and the characteristics of the second filter group are obtained by calculating the characteristic function g jammer The approximate solution of is calculated, where A transfer function matrix H represented by a matrix of M rows and L columns and representing the transfer characteristics from the input of the first filter group and the second filter group to the output of the M virtual microphones M×L , The characteristic function g is represented by a matrix of L rows and 1 column, and each component of the matrix of L rows and 1 column represents the characteristics of each filter in the first filter group and the characteristics of each filter in the second filter group. jammer ,and The objective function d is represented by a matrix of M rows and 1 column, and each component of the matrix of M rows and 1 column represents the target value of the power corresponding to the first interference sound outputted from the M virtual microphones and the target value of the power corresponding to the second interference sound outputted from the M virtual microphones. jammer , Satisfy H M×L *g jammer =d jammer relationship.

4. The sound processing device according to claim 2, wherein: The first speaker set and the second speaker set have a total of L speakers. Assume that M virtual microphones are virtually arranged in the entire partition including the first partition and the second partition, The characteristics of the third filter group and the characteristics of the fourth filter group are obtained by calculating the characteristic function g voice The approximate solution of is calculated, where A transfer function matrix H represented by a matrix of M rows and L columns and representing the transfer characteristics from the input of the third filter group and the fourth filter group to the output of the M virtual microphones M×L , The characteristic function g is represented by a matrix of L rows and 1 column, and each component of the matrix of L rows and 1 column represents the characteristics of each filter in the third filter group and the characteristics of each filter in the fourth filter group. voice ,and The objective function d is represented by a matrix of M rows and 1 column, and each component of the matrix of M rows and 1 column represents the target value of the power corresponding to the first broadcast sound outputted from the M virtual microphones and the target value of the power corresponding to the second broadcast sound outputted from the M virtual microphones. voice , Satisfy H M×L *g voice =d voice relationship.

5. The sound processing device according to claim 1, wherein: A first low-pass filter is provided before the first filter group and the second filter group. The first low-pass filter outputs a first low-frequency signal by cutting off a high-frequency component of a first source signal which is a source signal of the first and second interfering sounds.

6. The sound processing device according to claim 2, wherein: A second low-pass filter is provided before the third filter group and the fourth filter group. The second low-pass filter outputs a second low-frequency signal by cutting off high-frequency components of a second source signal which is a source signal of the first and second broadcast sounds.

7. The sound processing device according to claim 6, wherein: A first low-pass filter is provided at the front stage of the first filter group and the second filter group, and the first low-pass filter outputs a first low-frequency signal as the first sound signal by cutting off the high-frequency component of the first source signal which is the source signal of the first interfering sound and the second interfering sound, The first source signal is separated into the first low-frequency signal and the first high-frequency signal by passing through the first low-pass filter and the first high-pass filter provided in parallel with the first low-pass filter. The signal of the first low-frequency signal that has passed through the first filter group is synthesized with a signal whose amplitude of the first high-frequency signal is adjusted by the first amplifier group provided at the rear stage of the first high-pass filter, and then input to the first speaker set. The signal of the first low-frequency signal that has passed through the second filter group is synthesized with a signal whose amplitude of the first high-frequency signal is adjusted by the second amplifier group provided at the rear stage of the first high-pass filter, and then input to the second speaker set. The second source signal is separated into the second low-frequency signal and the second high-frequency signal by passing through the second low-pass filter and a second high-pass filter provided in parallel with the second low-pass filter. The signal of the second low-frequency signal after passing through the third filter group is synthesized with the signal of the second high-frequency signal whose amplitude is adjusted by the third amplifier group provided at the rear stage of the second high-pass filter, and then input to the first speaker set. The signal of the second low-frequency signal after passing through the fourth filter group is synthesized with the signal of the second high-frequency signal whose amplitude is adjusted by the fourth amplifier group provided at the rear stage of the second high-pass filter, and then input to the second speaker set. A cutoff frequency of the first low-pass filter, a cutoff frequency of the first high-pass filter, a cutoff frequency of the second low-pass filter, and a cutoff frequency of the second high-pass filter are substantially equal to each other.

8. The sound processing device according to claim 1, wherein: The first filter group and the second filter group are formed of FIR filters.

9. The sound processing device according to claim 2, wherein: The third filter group and the fourth filter group are formed of FIR filters.

10. A vehicle audio system, comprising: The first speaker set is arranged in the first zone; a second speaker set disposed in a second partition adjacent to the first partition; and A sound processing device comprising a first filter group for controlling a first interfering sound output from the first speaker set, a second filter group for controlling a second interfering sound output from the second speaker set, a third filter group for controlling a first broadcast sound output from the first speaker set, and a fourth filter group for controlling a second broadcast sound output from the second speaker set, The characteristics of the first filter group and the characteristics of the second filter group are set so that the total volume of the first interfering sound and the volume of the second interfering sound audible in the second partition is greater than the total volume of the first interfering sound and the volume of the second interfering sound audible in the first partition, The characteristics of the third filter group and the characteristics of the fourth filter group are set so that the total volume of the first broadcast sound and the volume of the second broadcast sound audible in the first partition is greater than the total volume of the first broadcast sound and the volume of the second broadcast sound audible in the second partition.

11. The in-vehicle audio system according to claim 10, wherein: The first partition corresponds to a driver's seat of the vehicle, and the second partition corresponds to a passenger seat of the vehicle. The first speaker set is a headrest speaker set provided on the headrest of the driver's seat, The second speaker set is a headrest speaker set provided on the headrest of the passenger seat.

12. The in-vehicle audio system according to claim 10, wherein: The first partition corresponds to a driver's seat of the vehicle, and the second partition corresponds to a passenger seat of the vehicle. The first speaker set is a seat back speaker set provided on the seat back of the driver's seat, The second speaker set is a seat back speaker set provided on a seat back of the passenger seat.

13. The in-vehicle audio system according to claim 10, wherein: The first partition corresponds to a driver's seat of the vehicle, and the second partition corresponds to a passenger seat of the vehicle. The first speaker set is a ceiling speaker set provided in a portion above the driver's seat in the ceiling of the vehicle. The second speaker set is a ceiling speaker set provided in a portion of the ceiling above the passenger seat.

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