Audio system
By using an audio system combining microphones and speakers and employing crosstalk and noise detection components to calculate gain adjustment, the problem of noise environment degradation when users in different seats in a car listen to different music is solved, achieving the effect of each person listening to music independently.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ALPS ALPINE CO LTD
- Filing Date
- 2025-11-11
- Publication Date
- 2026-05-19
AI Technical Summary
When the driver and passenger in a car are listening to different music, existing technology requires outputting pseudo-noise to mask the other's music, but this leads to a deterioration of the noise environment.
By employing a combination of microphone and speaker, and through crosstalk and noise detection components, the gain adjustment is calculated to reduce crosstalk and noise signals, ensuring that one user cannot hear the other's music while maintaining a good noise environment.
This allows the driver and front passenger to listen to their own music without compromising the noise environment, thus avoiding noise pollution.
Smart Images
Figure CN122069459A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to an audio system. Background Technology
[0002] As a technique for controlling the sound field so that the sound that is the object of a user’s listening can only be heard by that user, the following technique is known: outputting the object of a listening from a loudspeaker to a first area where the user is located, while simultaneously outputting pseudo-noise from the loudspeaker to a second area, such as an area where other people are located, to suppress the listening of the object of a listening (e.g., Patent Document 1).
[0003] Existing technical documents: Patent documents: Patent Document 1: Japanese Patent Application Publication No. 2019-83408 Summary of the Invention
[0004] The problem that the invention aims to solve: In a car, where the driver and front passenger are listening to different music, the goal is to ensure that one user can hear the music they are listening to while preventing the other user from hearing it.
[0005] Therefore, consider outputting pseudo-noise to one user to mask the music being listened to by the other user.
[0006] However, since this pseudo-noise is noise that does not actually exist, it degrades the noise environment for one user to listen to music.
[0007] Therefore, the objective of this invention is to output music to each user in a manner that prevents that user from hearing the music being listened to by the other user without deteriorating the noise environment in which the user is listening to the music.
[0008] Methods used to solve problems: To achieve the aforementioned objective, the present invention comprises: a first seat speaker disposed near a first seat in a vehicle; a microphone disposed near the head of a user sitting in the first seat; a second seat speaker disposed near a second seat in the vehicle; a first seat sound source outputting a first audio signal from the first seat speaker; a second seat sound source outputting a second audio signal; a gain adjustment unit that adjusts the gain of the second audio signal and outputs it to the second seat speaker; a crosstalk detection unit that extracts a component of the microphone output that includes the output sound of the second seat speaker as a crosstalk signal; a noise detection unit that extracts a component of the microphone output that excludes both the output sound of the first and second seat speakers as a noise signal; and a gain calculation unit that calculates the gain adjustment amount of the second audio signal in the gain adjustment unit such that the crosstalk signal is lower than the noise signal by a predetermined level. Here, the gain adjustment unit adjusts the gain of the second audio signal using the gain adjustment amount calculated by the gain calculation unit and then outputs it to the second seat speaker.
[0009] Alternatively, in this audio system, the crosstalk detection unit can remove the noise signal component and the output sound component of the first seat speaker from the output of the microphone to generate the crosstalk signal, and the noise detection unit can remove the output sound component of the first seat speaker and the output sound component of the second seat speaker from the output of the microphone to generate the noise signal.
[0010] In the audio system described above, the gain calculation unit may calculate the gain adjustment amount of the second audio signal in the gain adjustment unit according to each specified frequency band, in a manner that makes the crosstalk signal lower than the noise signal by a specified level. The gain adjustment unit adjusts the gain of the second audio signal according to each frequency band by a gain adjustment amount calculated by the gain calculation unit for that frequency band.
[0011] Alternatively, in the above audio system, one of the first seat and the second seat can be the driver's seat, and the other can be the front passenger seat.
[0012] According to such an audio system, the gain of the second audio signal directed to the second seat can be adjusted to a level that the user in the first seat cannot hear, while suppressing the adjustment amount with noise to a level that makes the user in the first seat unable to hear the second audio signal, thus minimizing any obstruction to the user in the second seat's ability to hear the second audio signal.
[0013] Invention effects: As described above, according to the present invention, music can be output to each user in a manner that prevents the user of one side from hearing the music being listened to by the user of the other side without deteriorating the noise environment in which the user of one side is listening to the music. Attached Figure Description
[0014] Figure 1 This is a diagram illustrating the configuration of an audio system according to an embodiment of the present invention.
[0015] Figure 2 This is a diagram illustrating an example of the configuration of a microphone and a speaker according to an embodiment of the present invention.
[0016] Figure 3 This is a diagram illustrating the configuration of the crosstalk detection unit according to an embodiment of the present invention.
[0017] Figure 4 This is a diagram showing the configuration of the noise detection unit according to an embodiment of the present invention.
[0018] Figure 5 This diagram illustrates the configuration of the gain calculation unit and the gain adjustment unit per frequency band according to an embodiment of the present invention.
[0019] Explanation of reference numerals in the attached figures: 1… Crosstalk detection unit, 2… Noise detection unit, 3… Gain calculation unit, 4… Gain adjustment unit per frequency band, 11… First adaptive filter, 12… First adder, 13… Second adaptive filter, 14… Second adder, 21… Third adaptive filter, 22… Third adder, 23… Fourth adaptive filter, 24… Fourth adder, 31… Noise band segmentation unit, 32… Noise power calculation unit, 33… Crosstalk band segmentation unit, 34… Crosstalk power calculation unit, 35… Gain calculation unit, 41… Band segmentation unit, 42… Gain adjustment unit, 44… Band synthesis unit. Detailed Implementation
[0020] The embodiments of the present invention will be described below.
[0021] Figure 1 This describes the configuration of the audio system in this embodiment.
[0022] This audio system is a car-mounted system, as shown in the figure, which includes a microphone MC_P for the passenger seat, a speaker SP_P for the passenger seat, and a speaker SP_D for the driver's seat.
[0023] Here, as Figure 2As shown, the microphone MC_P for the passenger seat and the speaker SP_P for the passenger seat are positioned near the head of the user sitting in the passenger seat, such as in the headrest of the passenger seat, while the speaker SP_D for the driver's seat is positioned near the head of the user sitting in the driver's seat, such as in the headrest of the driver's seat.
[0024] return Figure 1 The audio system has a sound source AS_P for the passenger seat and a sound source AS_D for the driver's seat. The audio signal of the sound source AS_P for the passenger seat is output from the speaker SP_P for the passenger seat, and the audio signal of the sound source AS_D for the driver's seat is output from the speaker SP_D for the driver's seat.
[0025] Furthermore, in this embodiment, the output of the speaker SP_D for the driver's seat is adjusted to a level that prevents the user sitting in the passenger seat from hearing the audio signal of the sound source AS_D for the driver's seat.
[0026] In addition, the audio system includes a crosstalk detection unit 1, a noise detection unit 2, a gain calculation unit 3, and a gain adjustment unit per frequency band 4.
[0027] The gain adjustment unit 4 per frequency band is a so-called equalizer. According to the gain control signal G output by the gain calculation unit 3, it adjusts the gain of the audio signal of the sound source AS_D for the driver's seat and outputs it to the speaker SP_D for the driver's seat for each frequency band of 1 / 3 octave band.
[0028] The crosstalk detection unit 1 takes the output of the microphone MC_P used in the passenger seat as the microphone input signal Min, and the output of the speaker SP_D used in the driver's seat as SP_OUT_D. It extracts the component of the speaker SP_D output SP_OUT_D in the microphone input signal Min as the crosstalk signal CT.
[0029] The noise detection unit 2 takes the output of the speaker SP_P used in the passenger seat as SP_OUT_P, and extracts the components in the microphone input signal Min other than the components of the speaker SP_D output SP_OUT_D and the components of the speaker SP_P output SP_OUT_P as the noise signal NZ.
[0030] Here, the noise signal NZ includes components of environmental noise, such as road noise, which are unrelated to the audio system, as the main components.
[0031] The gain calculation unit 3 calculates the gain of the per-band gain adjustment unit 4 for each frequency band of the audio signal attenuation crosstalk signal CT of the sound source AS_D for the driver's seat according to the amount of excess relative to the level of the noise signal NZ, and outputs a gain control signal G for controlling the gain of the per-band gain adjustment unit 4 to the calculated gain.
[0032] then, Figure 3 The configuration of the crosstalk detection unit 1 is shown.
[0033] As shown in the figure, the crosstalk detection unit 1 includes a first adaptive filter 11, a first adder 12, a second adaptive filter 13, and a second adder 14.
[0034] The first adaptive filter 11 is an adaptive filter that takes the noise signal NZ as input. The first adder 12 outputs the signal after subtracting the output of the first adaptive filter 11 from the microphone input signal Min.
[0035] Furthermore, the first adaptive filter 11 sets its own transfer function (filter coefficients) in a way that minimizes the output of the first adder 12.
[0036] Therefore, the output of the first adder 12 becomes the signal after removing the noise signal NZ from the microphone input signal Min.
[0037] Next, the second adaptive filter 13 is an adaptive filter that takes the output SP_OUT_P of the speaker SP_P for the passenger seat as input, and the second adder 14 outputs the result after subtracting the output of the second adaptive filter 13 from the first adder 12.
[0038] Furthermore, the second adaptive filter 13 sets its own transfer function (filter coefficients) in a way that minimizes the output of the second adder 14.
[0039] Therefore, the output of the second adder 14 becomes the signal after removing the components of the noise signal NZ and the components of the output signal SP_OUT_P (the output component of the speaker SP_P for the passenger seat) from the microphone input signal Min. That is, it becomes the signal of the surround component (crosstalk) in the microphone input signal Min that represents the output of the speaker SP_D for the driver's seat, and this signal is output as the crosstalk signal CT.
[0040] then, Figure 4 This indicates the configuration of the noise detection unit 2.
[0041] As shown in the figure, the noise detection unit 2 includes a third adaptive filter 21, a third adder 22, a fourth adaptive filter 23, and a fourth adder 24.
[0042] The third adaptive filter 21 is an adaptive filter that takes the output SP_OUT_P of the speaker SP_P used in the passenger seat as its input. The third adder 22 outputs the signal after subtracting the output of the third adaptive filter 21 from the microphone input signal Min.
[0043] Furthermore, the third adaptive filter 21 sets its own transfer function (filter coefficients) in a way that minimizes the output of the third adder 22.
[0044] Therefore, the output of the third adder 22 becomes the signal after removing the component of the output SP_OUT_P of the speaker SP_P for the passenger seat from the microphone input signal Min.
[0045] Next, the fourth adaptive filter 23 is an adaptive filter that takes the output SP_OUT_D of the driver's seat speaker SP_D as input, and the fourth adder 24 outputs the result after subtracting the output of the fourth adaptive filter 23 from the third adder 22.
[0046] Furthermore, the fourth adaptive filter 23 sets its own transfer function (filter coefficients) in a way that minimizes the output of the fourth adder 24.
[0047] Therefore, the output of the fourth adder 24 becomes the signal after removing the components of the output signal SP_OUT_P (the output component of the speaker SP_P for the passenger seat) and the surround component (crosstalk) of the output of the speaker SP_D for the driver's seat from the microphone input signal Min. That is, it becomes the signal representing the noise component in the microphone input signal Min, which is output as the noise signal NZ.
[0048] then, Figure 5 This indicates the configuration of the gain calculation unit 3 and the gain adjustment unit per frequency band 4.
[0049] As shown in the figure, the gain calculation unit 3 includes a noise frequency band segmentation unit 31, a noise power calculation unit 32, a crosstalk frequency band segmentation unit 33, a crosstalk power calculation unit 34, and a gain calculation unit 35.
[0050] The noise band segmentation unit 31 segments the noise signal NZ into 1 / 3 octave bands, and the noise power calculation unit 32 calculates the power of the noise signal NZ in each segmented band.
[0051] The crosstalk band segmentation unit 33 divides the crosstalk signal CT into 1 / 3 octave bands, and the crosstalk power calculation unit 34 calculates the power of the crosstalk signal CT in each segmented band.
[0052] The gain calculation unit 35 calculates the gain of the gain adjustment unit 4 for each frequency band by attenuating the gain-adjusted audio signal SP_OUT_D output by the gain adjustment unit 4 of each frequency band by adding a margin to the amount by which the power of the crosstalk signal CT is attenuated relative to the power of the noise signal NZ. In other words, it calculates the gain by reducing the power of the crosstalk signal CT relative to the power of the noise signal NZ by a predetermined level, and outputs this gain as a gain control signal G to the gain adjustment unit 4 of each frequency band. More specifically, the gain calculation unit 35 calculates the gain of the gain adjustment unit 4 for each frequency band by attenuating the gain-adjusted audio signal SP_OUT_D output by the gain adjustment unit 4 of each frequency band by reducing the power of the crosstalk signal CT relative to the power of the noise signal NZ by an amount by which the power of the crosstalk signal CT is reduced to less than or equal to the power of the noise signal NZ, and outputs this gain as a gain control signal G to the gain adjustment unit 4 of each frequency band.
[0053] However, the gain calculation unit 35 calculates the gain with an attenuation of 0 for the frequency band where the power of the crosstalk signal CT is lower than the power of the noise signal NZ.
[0054] In addition, multiple groups of gains for each frequency band can be prepared in advance, and the group with the smallest attenuation where the power of the crosstalk signal CT is lower than the power of the noise signal NZ in all frequency bands can be used as the gain control signal G.
[0055] Alternatively, a lower limit can be set for the gain calculated by the gain calculation unit 35 for each frequency band.
[0056] Next, each frequency band gain adjustment unit 4 includes a frequency band segmentation unit 41, a gain adjustment unit 42, and a frequency band synthesis unit 44.
[0057] The noise masking band segmentation unit divides the audio signal of the sound source AS_D for the driver's seat into each band of 1 / 3 octave. The gain adjustment unit adjusts the gain of the audio signal according to the gain control signal G input from the gain calculation unit 3 for each segmented band. The band synthesis unit 44 synthesizes the adjusted audio signals of each band and outputs them to the speaker SP_D for the driver's seat.
[0058] The embodiments of the present invention have been described above.
[0059] Thus, according to this embodiment, the gain of the audio signal output to the driver's seat can be adjusted to a level that the passenger in the front seat cannot hear, while the adjustment amount is suppressed to a level that the passenger in the front seat cannot hear with noise, so as not to hinder the driver's listening to the audio signal facing the driver's seat as much as possible.
[0060] Here, the above shows a case where the output of the speaker SP_D for the driver's seat is adjusted to a level that prevents the user in the passenger seat from hearing the audio signal of the sound source AS_D for the driver's seat. However, the audio system can also have a configuration that is symmetrical to the above configuration with respect to the passenger seat and the driver's seat, and the output of the speaker SP_P for the passenger seat is also adjusted to a level that prevents the user in the driver's seat from hearing the audio signal of the sound source AS_P for the passenger seat.
[0061] In addition, the driver's seat and the front passenger seat in the above embodiments can be replaced with any two seats in the car.
Claims
1. An audio system, characterized in that, have: The first-seat speaker is positioned near the first seat of the car; A microphone is positioned near the head of the user seated in the first seat; The second-seat speaker is located near the second seat of the car; The first seat is used as a sound source, and the first audio signal is output from the speaker in the first seat. The second seat uses a sound source to output a second audio signal; The gain adjustment unit adjusts the gain of the second audio signal and outputs it to the second seat speaker; The crosstalk detection unit extracts the component of the output sound of the second seat speaker included in the output of the microphone as a crosstalk signal; The noise detection unit extracts the components from the microphone output that do not include the output sound of the first seat speaker and the output sound of the second seat speaker as a noise signal. as well as The gain calculation unit calculates the gain adjustment amount of the second audio signal in the gain adjustment unit in a manner that makes the crosstalk signal lower than the noise signal by a predetermined level. The gain adjustment unit adjusts the gain of the second audio signal using the gain adjustment amount calculated by the gain calculation unit, and then outputs it to the speaker for the second seat.
2. The audio system according to claim 1, characterized in that, The crosstalk detection unit removes the noise signal component and the output sound component of the first seat speaker from the microphone output to generate the crosstalk signal.
3. The audio system according to claim 1, characterized in that, The noise detection unit removes the components of the output sound from the first seat speaker and the output sound from the second seat speaker from the output of the microphone to generate the noise signal.
4. The audio system according to claim 1, characterized in that, The crosstalk detection unit removes the noise signal component and the output sound component of the first seat speaker from the microphone output to generate the crosstalk signal. The noise detection unit removes the components of the output sound from the first seat speaker and the output sound from the second seat speaker from the output of the microphone to generate the noise signal.
5. The audio system according to any one of claims 1 to 4, characterized in that, The gain calculation unit calculates the gain adjustment amount of the second audio signal in the gain adjustment unit for each specified frequency band in a manner that makes the crosstalk signal lower than the noise signal by a specified level. The gain adjustment unit adjusts the gain of the second audio signal according to each frequency band by a gain adjustment amount calculated by the gain calculation unit for that frequency band.
6. The audio system according to any one of claims 1 to 4, characterized in that, One of the first seat and the second seat is the driver's seat, and the other is the front passenger seat.