Acoustic system

Abstract

To provide a "acoustic system" which outputs a notification sound easy to hear for a specific user in a range which does not give troublesomeness to the other user.SOLUTION: A notification sound outputted from a notification sound source 1 is outputted from a speaker 3, which is disposed in a headrest of a driver seat, toward a driver after a gain is adjusted by a variable gain amplifier 2. A gain setting section 5 estimates power of noise in each seat from sounds collected by a microphone 4 and by using a transfer function Cd of the notification sound from the speaker 3 to a user on the driver seat and a transfer function Ct of the notification sound from the speaker 3 to a user on a specific seat, the transfer functions being calculated beforehand, a gain of the notification sound is calculated with which a volume of the notification sound becomes higher than noise on the driver seat and the volume of the notification sound becomes lower than noise on the specific seat, and set to the variable gain amplifier 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a technique for outputting sound directed to a specific user without annoying other users. [Background technology]

[0002] A known technology for outputting sound directed at a specific user without bothering other users is to install a speaker in the headrest of a car seat and output sound from the speaker toward the user seated in that seat (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-95646 A Summary of the Invention [Problem to be solved by the invention]

[0004] Even when sound is output from a speaker installed in the headrest of a car seat toward a user seated in that seat, if the volume is too high, other users will hear the sound output from the speaker, causing annoyance. On the other hand, if the volume is lowered to a level that always ensures that other users cannot hear the sound, the sound output from the speaker will be difficult for the user seated in that seat to hear.

[0005] Therefore, an object of the present invention is to output a sound that is easily audible to a specific user, to a specific user, without causing annoyance to other users. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides an acoustic system that outputs a sound output from a sound source as a notification sound to a user seated in a first seat among a plurality of seats arranged in a room, the acoustic system comprising: a speaker arranged at a position closest to the user seated in the first seat among the users seated in the seats; a gain adjustment means that adjusts the level of the sound output from the sound source with a set gain and outputs the sound to the speaker as the notification sound; a gain setting means that sets the gain in the gain adjustment means, in which a first transfer function that is a transfer function from the speaker of the notification sound to the user seated in the first seat and a second transfer function that is a transfer function from the speaker of the notification sound to a user seated in a second seat that is different from the first seat among the plurality of seats are preset; and a microphone that picks up noise in the room. Here, the gain setting means estimates the noise level at each seat from the noise picked up by the microphone, and calculates a notification sound gain based on the estimated noise level, the first transfer function, and the second transfer function, such that the notification sound is louder than the noise at the position of the user seated in the first seat and quieter than the noise at the position of the user seated in the second seat, and sets the gain in the gain adjustment means.

[0007] Here, in this acoustic system, the gain setting means sets the estimated noise power at each seat to P N The power of the signal obtained by convolving the sound output from the sound source with the first transfer function is P X , the first transfer function is C d , the second transfer function is C t The gain to be set in the gain adjustment means is A, A = α(P N / P X ) 1<α <C d / C t The gain to be set in the gain adjustment means may be calculated so as to satisfy the following:

[0008] In the above sound system, the interior may be the interior of an automobile. In order to achieve the above object, the present invention provides an audio system that outputs a sound output from a sound source as a notification sound to a user seated in a first seat among a plurality of seats arranged in a vehicle cabin, the audio system including a speaker arranged at a position closest to the user seated in the first seat among the users seated in each seat, a gain adjustment means that adjusts the level of the sound output from the sound source with a set gain and outputs the sound to the speaker as the notification sound, a gain setting means that sets the gain to the gain adjustment means, in which a first transfer function that is a transfer function from the speaker of the notification sound to the user seated in the first seat and a second transfer function that is a transfer function from the speaker of the notification sound to a user seated in a second seat that is different from the first seat among the plurality of seats are preset, and a microphone that picks up noise in the vehicle cabin. Here, the gain setting means estimates the magnitude of the noise in each seat from the noise picked up by the microphone, and calculates the power of the estimated noise in each seat as P N The power of the signal obtained by convolving the first transfer function with a signal obtained by adjusting the level of the sound output from the sound source with the gain set by the gain adjustment means is P XA The power of the signal obtained by convolving the second transfer function with a signal obtained by adjusting the level of the sound output from the sound source with the gain set by the gain adjustment means is P XA As, -0.41P N +34.71 <P XA / P N <-0.71P N +57.03, and, P TA / P N <-0.41P N +34.71 The gain to be set in the gain adjustment means is calculated so as to satisfy the following as much as possible.

[0009] Here, in the above-mentioned acoustic system in which the interior is the interior of a vehicle, the first seat may be a driver's seat of the vehicle. In this case, the speaker is preferably provided in a headrest of the driver's seat. In this case, the second seat may be a seat in the vehicle excluding the driver's seat that has the largest gain of the transfer function from the speaker of the notification sound to the user sitting in that seat, or a seat selected by the user from among the seats in the vehicle excluding the driver's seat.

[0010] With the above-described audio system, a notification sound can be output to a user in the first seat at a level that will not be drowned out by noise, while a notification sound can be output so that a user in the second seat cannot hear the notification sound clearly because it is masked by noise. Effect of the Invention

[0011] As described above, according to the present invention, it is possible to output a sound that is easily audible to a specific user, to a specific user, without causing annoyance to other users. [Brief description of the drawings]

[0012] [Figure 1] 1 is a block diagram showing a configuration of an audio system according to an embodiment of the present invention. [Diagram 2] 1 is a diagram showing an arrangement of microphones and speakers in an audio system according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a diagram showing a transfer function taken into account in an audio system according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram illustrating an example of volume control of the audio system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described. FIG. 1 shows the configuration of an audio system according to this embodiment. The audio system is a system installed in an automobile, and as shown in the figure, includes a notification sound source 1 that outputs a notification sound, a variable gain amplifier 2 with a variable gain A, a speaker 3, a microphone 4, a gain setting unit 5, and a control unit 6. The notification sound output by the notification sound source 1 is, for example, a sound that represents driving information for the driver, such as a message voice or a warning sound for a car navigation system. The notification sound output from the notification sound source 1 has its power adjusted by the variable gain amplifier 2 and is output from the speaker 3. The gain A of the variable gain amplifier 2 is set by a gain setting unit 5. Next, as shown in FIGS. 2a and 2b, the speaker 3 is disposed in the headrest of the driver's seat so as to output a notification sound to the driver seated in the driver's seat. Furthermore, the microphone 4 picks up noises inside the vehicle such as engine noise, road noise, etc. The microphone 4 can be disposed, for example, in a central position inside the vehicle on the ceiling. The setting of the gain A of the variable gain amplifier 2 performed by the gain setting unit 5 will be described below. For this setting, a transfer function in the target frequency range from the notification sound speaker 3 to the user seated at each seat is used. The target frequency range is the frequency range of the notification sound, for example, 100 Hz to 1 kHz, which is the frequency range of the human voice. In the following, as shown in Fig. 3, the transfer function in the target frequency range from the speaker 3 placed in the headrest of the driver's seat to the user (driver) sitting in the driver's seat is defined as C d where i is the seat number of each seat other than the driver's seat, and the transfer function in the target frequency range from speaker 3 to the users sitting in each seat other than the driver's seat is C i (In the figure, C 1 From C 6 ) where speaker 3 is placed in the headrest of the driver's seat, so the transfer function of the driver's seat is C d The gain of the other seat's transfer function C i The gain is significantly larger than that of

[0014] Returning to Figure 1, the transfer function C d , the transfer function C i is obtained in advance for each vehicle type by actual measurement or the like and stored in the control unit 6. The control unit 6 calculates the transfer function C dis set in the gain setting unit 5, and a transfer function corresponding to a specific seat other than the driver's seat is set as a target transfer function C t is set in the gain setting unit 5. Hereinafter, for convenience, the target transfer function C set in the gain setting unit 5 is t In this explanation, we will refer to the seat corresponding to the above as the "target seat." Target transfer function C t As for the transfer function C i Alternatively, a transfer function corresponding to a seat (eg, a VIP seat) set as a target seat by the user among the seats other than the driver's seat is set.

[0015] Here, the target transfer function C t As for the transfer function C i The transfer function with the largest gain among the above may be fixed. In this case, the transfer function C d and the transfer function C i The target transfer function C t Alternatively, the control unit 6 may store only the transfer function C d and the transfer function C i Without memorizing the driver's seat transfer function C d and the target transfer function C t The transfer function to be set as above may be set in the gain setting unit 5 in advance.

[0016] Driver's seat transfer function C d and the target transfer function C t The gain setting unit 5, which has been set to the power P N Here, the level of the noise inside the vehicle, such as engine noise and road noise, is uniformly the same throughout the vehicle, so the power P calculated from the noise picked up by the microphone 4 is N can be used to represent the noise power at each seat in the vehicle.

[0017] The gain setting unit 5 determines the noise power P N The notification sound input from the notification sound source 1 and the transfer function C of the driver's seat that is set d and the target transfer function C t Then, the gain A is calculated using the following formula and set in the variable gain amplifier 2. A = α(P N / P X ) 1<α <C d / C t However, P X is the transfer function C of the driver's seat to the notification sound (without gain adjustment) input from notification sound source 1. d is the power of the signal convolved with

[0018] Here, when α=1, A=P N / P X The power of the notification sound transmitted to the user in the driver's seat is A·P X teeth, A.P. X =(P N / P X )·P X =P N Therefore, the SNR for the notification sound noise in the driver's seat is 0 dB.

[0019] On the other hand, α=C d / C t When, A=(C d / C t )·(P N / P X ) and the power of the notification sound transmitted to the user at the target seat is C t ·A·(P X / C d )teeth, C t ·A·(P X / C d )=C t ·(C d / C t )·(P N / P X )·(P X / C d )=(Ct C d P N P X ) / (C t P X C d )=P N Therefore, the SNR of the notification sound to noise at the target seat is 0 dB.

[0020] Therefore, 1<α <C d / C t By calculating and setting the gain A so as to satisfy the above condition, the volume of the notification sound can be adjusted and output from the speaker 3 so that the notification sound is louder than the noise in the driver's seat and quieter than the noise in the target seat.

[0021] Therefore, while the user in the driver's seat can hear the notification sound without it being drowned out by noise, the user in the target seat cannot hear the notification sound clearly as it is masked by noise. Here, the gain A is 1<α <C d / C t You can set the maximum value within the range that satisfies the condition of 1 < α <C d / C t Alternatively, the gain may be set so as to be closest to a preset standard gain within a range that satisfies the above condition.

[0022] The target transfer function C t As the transfer function C i If the transfer function with the largest gain is set, the notification sound will be transmitted most loudly to the target seat among the seats other than the driver's seat. Therefore, by calculating and setting the gain A as described above, the notification sound will be smaller than the noise in all seats other than the driver's seat.

[0023] The gain A may be set in the gain setting section 5 as follows. The ITU recommendation "Recommendation ITU-T P.1150, In-car communication audio specification" indicates that the SNR between Upper y and Lower y in the following formula is the preferable SNR for speech with respect to noise level x. Upper;y=-0.71x+57.03 Lower;y=-0.41x+34.71 Therefore, the notification sound is adjusted with gain A and the driver's seat transfer function C d The power of the convoluted signal is P XA The SNR of the driver's seat notification sound is P XA / P N The notification sound is adjusted with gain A and the target transfer function C is t The power of the convoluted signal is P TA Let the SNR of the notification sound at the target seat be P TA / P N Expressed as: -0.41P N +34.71 <P XA / P N <-0.71P N +57.03 In this case, the SNR of the notification sound in the driver's seat will be between Upper and Lower, and the user in the driver's seat can hear the notification sound at a preferred SNR.

[0024] on the other hand, P TA / P N <-0.41P N +34.71 In this case, the SNR of the notification sound at the target seat will be below Lower, and the notification sound will be masked by noise and will not be able to be heard clearly.

[0025] So, -0.41P N +34.71 <P XA / P N <-0.71P N +57.03 and P TA / P N <-0.41P NCalculate and set the gain A to satisfy +34.71. For example, as shown in Fig. 4, the median value between the Upper and Lower noise levels is set as the Target, and the SNR at the driver's seat is set as the noise power P N The gain A obtained to be the target for P TA / P N <-0.41P N If it satisfies +34.71, the gain A obtained so as to achieve the target is set in the variable gain amplifier 2.

[0026] The black circles in Fig. 4 represent the SNR at the driver's seat with the gain A set in this way, and the diamonds represent the SNR at the target seat with this gain A. As shown in the figure, at different noise levels such as when idling or traveling at 60 km, the notification sound can be heard at a preferred SNR for the user in the driver's seat, while the notification sound can be masked by noise in the target seat so that it cannot be clearly heard.

[0027] On the other hand, the gain A obtained to be the target is P TA / P N <-0.41P N If +34.71 is not met, -0.41P N +34.71 <P XA / P N And P TA / P N <-0.41P N Find the maximum gain A that satisfies +34.71 and set it as variable gain amplifier 2.

[0028] Also, -0.41P N +34.71 <P XA / P N And P TA / P N <-0.41P N If there is no gain A that satisfies +34.71, then -0.41P is used as the specified margin with M. N +34.71+M=P XA / P NThe gain A that satisfies the above is calculated and set to the variable gain amplifier 2.

[0029] The embodiment of the present invention has been described above. In the above embodiment, the speaker 3 is provided in the headrest of the driver's seat, but the speaker 3 may be provided in another position that is closest to the user seated in the driver's seat among the users seated in the seats. In addition, the above embodiments have shown a case in which control is performed so that a user seated in the driver's seat can hear the notification sound and users seated in other seats cannot clearly hear the notification sound, but the above can be similarly applied to a case in which control is performed so that a user seated in a specific seat other than the driver's seat can hear the notification sound and users seated in seats other than the specific seat cannot clearly hear the notification sound by exchanging the relationship between the driver's seat and the specific seat in the above description.

[0030] Furthermore, although the above embodiments have been described as being applied to the interior of an automobile, this embodiment may also be applied to any interior room in which multiple seats are fixedly provided, so that a user seated in a specific seat within the interior room can hear the notification sound, while users seated in other seats cannot clearly hear the notification sound. [Explanation of symbols]

[0031] 1...notification sound source, 2...variable gain amplifier, 3...speaker, 4...microphone, 5...gain setting unit, 6...control unit.

Claims

1. An audio system that outputs a sound output from a sound source as a notification sound to a user who is seated in a first seat among a plurality of seats arranged in a room, a speaker disposed at a position closest to the user seated in the first seat among the users seated in the respective seats; a gain adjustment means for adjusting a level of a sound output from the sound source with a set gain and outputting the sound as the notification sound to the speaker; a gain setting means for setting the gain in the gain adjustment means, in which a first transfer function which is a transfer function from the speaker of a notification sound to a user seated in the first seat and a second transfer function which is a transfer function from the speaker of a notification sound to a user seated in a second seat different from the first seat among a plurality of seats are preset; A microphone for collecting noise in the room, The gain setting means estimates the noise level at each seat from the noise picked up by a microphone, and calculates a gain for the notification sound such that the notification sound is louder than the noise at the position of the user seated in the first seat and quieter than the noise at the position of the user seated in the second seat based on the estimated noise level, the first transfer function, and the second transfer function, and sets the gain in the gain adjustment means.

2. 2. The audio system of claim 1, The gain setting means The estimated noise power at each seat is P N The power of the signal obtained by convolving the sound output from the sound source with the first transfer function is P X , the first transfer function is C d , the second transfer function is C t , the gain to be set in the gain adjustment means is A, A=α(P N / P X ) 1<α<C d / C t The acoustic system according to claim 1, wherein the gain to be set in the gain adjustment means is calculated so as to satisfy the following:

3. An audio system that outputs a sound output from a sound source as a notification sound to a user seated in a first seat among a plurality of seats arranged in a vehicle interior, a speaker disposed at a position closest to the user seated in the first seat among the users seated in the respective seats; a gain adjustment means for adjusting a level of a sound output from the sound source with a set gain and outputting the sound as the notification sound to the speaker; a gain setting means for setting the gain in the gain adjustment means, in which a first transfer function which is a transfer function from the speaker of a notification sound to a user seated in the first seat and a second transfer function which is a transfer function from the speaker of a notification sound to a user seated in a second seat different from the first seat among a plurality of seats are preset; A microphone that picks up noise in the vehicle cabin, The gain setting means estimates the noise level at each seat from the noise picked up by the microphone, and sets the estimated noise power at each seat as P N The power of the signal obtained by convolving the first transfer function with a signal obtained by adjusting the level of the sound output from the sound source with the gain set by the gain adjustment means is P XA The power of the signal obtained by convolving the second transfer function with a signal obtained by adjusting the level of the sound output from the sound source with the gain set by the gain adjustment means is P XA As, -0.41P N +34.71<P XA / P N <-0.71P N +57.03、 and, P TA / P N <-0.41P N +34.71 The gain to be set in the gain adjustment means is calculated so as to satisfy the following as much as possible.

4. 2. The audio system of claim 1, The acoustic system according to claim 1, wherein the interior is the interior of an automobile.

5. 3. The audio system of claim 2, The acoustic system according to claim 1, wherein the interior is the interior of an automobile.

6. 6. An acoustic system according to claim 3, 4 or 5, 13. The audio system according to claim 12, wherein the first seat is a driver's seat of the automobile.

7. 7. The audio system of claim 6, The sound system is characterized in that the speaker is provided in a headrest of the driver's seat.

8. 7. The audio system of claim 6, The second seat is an acoustic system characterized in that it is a seat, excluding the driver's seat of the automobile, in which the gain of the transfer function from the speaker of the notification sound to the user sitting in that seat is the largest.

9. 7. The audio system of claim 6, The acoustic system according to claim 1, wherein the second seat is a seat selected by a user from among the seats of the vehicle other than a driver's seat.

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