JPH06165298A - Acoustic reproduction device - Google Patents

Abstract

PURPOSE:To allow each of plural listeners to enjoys a music or the like with a same spread as if they were in an original sound field such as a concert hall in a reproduction sound field and to evaluate real noise. CONSTITUTION:A reverse filter network 5 is interposed between a recorder 2 recording acoustic information by the binaural recording system and amplifiers 4a-4d of speakers 3a-3d sounding, sound plural listeners being passengers L1, L2. Then the reverse filter network 5 is built up to erase crosstalk between the speakers 3a-3d and the passengers L1, L2 based on the acoustic transfer characteristic between the plural speakers 3a-3d and both ears of the passengers L1, L2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound reproducing device capable of reproducing sound having a realistic sensation similar to that existing in an original sound field, and particularly, it is effective for a plurality of people. It is the one.

[0002]

2. Description of the Related Art Acoustic information such as music in various sound fields such as a concert hall and noise in a vehicle compartment is recorded by microphones placed in both ears of a dummy head that simulates a human head, and the recorded acoustic information is recorded. There has been a sound reproducing device capable of listening to the same music and noise as if they were in the original sound field in the reproduced sound field by appropriately processing the sound with a digital filter and then reproducing the sound with a speaker.
(For example, Satoshi Miura, Journal of Acoustical Society, Vol. 46, No. 8 (1990) p63.
See 3-634. ) Here, an outline of such a conventional sound reproducing apparatus will be described with reference to FIGS. 16 to 18. That is, FIG.
As shown in FIG. 6, the sound reproduction device 1 is a recording device 2 that records sound information such as music by a binaural recording method.
And two speakers 3L and 3R arranged in front of the listener L and separated from each other to the left and right, amplifiers 4L and 4R provided for each of the speakers 3L and 3R, a recording device 2 and amplifiers 4L and 4
And an inverse filter network 5 interposed between R.

The acoustic information recorded in the recording device 2 is
As shown in FIG. 17, in the original sound field of a concert hall or the like, two left and right microphones MP _L and MP _R arranged at the binaural positions of the dummy head D were recorded as left and right separate recording sounds B ₁ and B ₂ , respectively. This is acoustic information, and such a recording method is called a binaural recording method. Therefore,
By properly reproducing the acoustic information recorded in the recording device 2, it is possible to listen to the same music as the original sound field in the reproduced sound field. However, even if the acoustic information recorded in the recording device 2 is simply reproduced, such an effect cannot be obtained. This is because it is considered that the inverse filter network 5 is not provided in the configuration shown in FIG. 16, and the recorded sound B ₁ recorded at the left ear position is reproduced by the speaker 3L and the recorded sound B ₂ recorded at the right ear position is reproduced. , The reproduction sound S ₁ from the speaker 3L reaches not only the left ear of the listener L but also the right ear and the reproduction sound S ₂ from the speaker 3R is only in the right ear of the listener L. Instead, so-called crosstalk occurs in that the sound reaches the left ear, and the sounds M ₁ and M ₂ heard by the listener L with the left and right ears are recorded sounds B ₁ and B.
_Because it does not match ₂ .

Therefore, in the sound reproducing device 1,
By constructing a filter capable of eliminating the above-mentioned crosstalk in the inverse filter network 5, the sounds M ₁ and M ₂ actually heard by the listener L are made to match the recorded sounds B ₁ and B _2. . Specifically, first, as shown in FIG. 18, the test signal generator 6 is connected to the amplifiers 4L and 4R, and the reproduced sound S corresponding to the test signal is output from the speakers 3L and 3R.
₁ and S ₂ are generated, and based on the reproduced sounds S ₁ and S ₂ and the sounds M ₁ and M ₂ measured at the binaural positions of the dummy head D, the speakers 3L and 3R and the binaural positions are compared. The acoustic transfer characteristics h ₁₁ , h ₁₂ , h ₂₁ , and h ₂₂ between them are identified.

Then, the identified acoustic transfer characteristics h
_{Using 11} , h ₁₂ , h ₂₁ , and h ₂₂ , the relationship between the reproduced sounds S ₁ and S ₂ and the measured sounds M ₁ and M ₂ has the following (1).
It is expressed as an expression.

[0006]

[Equation 1]

(1) On the other hand, in the configuration of FIG. 16, the target effect is

[0008]

[Equation 2]

(2) Therefore, if this equation (2) is transformed,

[0010]

[Equation 3]

.. (3) Therefore, if the reproduced sounds S ₁ and S ₂ are expressed by the following formula (4) from the formulas (1) and (3), the formula (2) is satisfied.

[0012]

[Equation 4]

(4) Therefore, the inverse filter network 5 interposed between the recording device 2 and the amplifiers 4L and 4R may be constructed so as to satisfy the following expression (5).

[0014]

[Equation 5]

(5) As a result, in the case of the conventional sound reproducing device 1 shown in FIG. 16, the listener L can enjoy music and make noise as if he / she is in the original sound field while in the reproduction sound field. Could be evaluated.

[0016]

However, in the conventional sound reproducing apparatus 1, since the single listener is used as a target, a plurality of persons existing in the same space can listen to music in the same manner. It was not possible to evaluate noise and noise. That is, even if a plurality of systems of the above-mentioned sound reproducing device are provided, the inverse filter network of each device can eliminate the crosstalk within its own device, but eliminates the crosstalk between each device. You can't do that.

The present invention has been made by paying attention to the unsolved problem of the conventional technique, and it is as if a plurality of listeners were in the original sound field while in the reproduced sound field. It is an object of the present invention to provide a sound reproducing device that can enjoy music and evaluate noise.

[0018]

In order to achieve the above-mentioned object, the sound reproducing apparatus according to the invention of claim 1 has N (N ≧ N) acoustic information recording means for recording acoustic information by a binaural recording system. 2) interposed between the sound generating means, the sound information recording means and the N sound generating means,
Based on the n × 2 × N sound transfer characteristics between the two ears of n listeners (n ≧ 2) and the N sound generators, the cross between the sound generators and the listeners. And an inverse filter network constructed to eliminate talk.

In order to achieve the above object, the sound reproducing apparatus according to the invention of claim 2 is a sound information recording means for recording sound information by a binaural recording system, and N.
N (n ≧ 3) sound generating means, and n (n ≧ 3) between the sound information recording means and the N sound generating means.
2) between the two ears of the listener and the (N-1) sound generators of the N sound generators that are the farthest from each listener. -1) An inverse filter network constructed so as to eliminate crosstalk between the sound generating means and the listener based on the sound transfer characteristics.

Further, in order to achieve the above object, the sound reproducing apparatus according to the invention of claim 3 is a sound information recording means for recording sound information by a binaural recording system,
N (N ≧ 3) sound generating means are interposed between the sound information recording means and the N sound generating means.
≧ 2) n × 2 between both ears of the listener and two of the N sound generating means which are close to each listener.
An inverse filter network constructed so as to eliminate crosstalk between the sound generating means and the listener based on the two sound transfer characteristics.

[0021]

According to the first aspect of the invention, the inverse filter network interposed between the acoustic information recording means and the sound generating means includes both ears of n listeners and N sound generating means. Since the crosstalk between the sound generating means and the listener can be eliminated based on the n × 2 × N sound transfer characteristics between them, one sound information recording means (that is, There is only one sound source in the sound reproduction device, but each listener will hear the same music and noise as in the original sound field.

According to the second aspect of the invention, the influence of the sound generating means farthest from each listener is considered to be negligible, and the sound farthest from both ears of each listener and each listener is considered. N × 2 excluding acoustic transfer characteristics with the generating means
Since the inverse filter network is constructed so as to eliminate crosstalk based on x (N-1) acoustic transfer characteristics, the same operation as the invention according to claim 1 can be obtained with a smaller calculation load. .

Further, in the invention according to claim 3,
Considering that the influence of the two sound generating means close to each listener is extremely larger than that of the other sound generating means, n × 2 × 2 between the two sound generating means close to each listener. Since the inverse filter network is constructed so that the crosstalk between the sound generating means and the listener can be eliminated based on the sound transfer characteristic of the above, the same operation as that of the invention according to claim 1 can be achieved. It can be obtained with a smaller calculation load than the invention described in 2.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing a first embodiment of the present invention, in which a sound reproducing device 1 according to the present invention is applied to a front seat of a vehicle. The present invention is applied to a device that allows _two occupants L ₁ and L ₂ as listeners in a room to hear the same music as in the original sound field of a concert hall or the like. In addition,
The same components as those of the above-described conventional sound reproducing device are designated by the same reference numerals.

That is, in the present embodiment, a total of four speakers 3a, which are arranged left and right in front of each of the _two occupants L ₁ and L ₂ lined up left and right on the front seat of the vehicle, Three
b, 3c and 3d, and each speaker 3a-
Each of 3d is connected to the amplifiers 4a, 4b, 4c and 4d, and these speakers 3a to 3d and the amplifier 4 are connected.
The sound generating means is constituted by each set of a to 4d. The speakers 3a to 3d are fixed, for example, to a dash panel arranged in the front part of the vehicle interior facing the vehicle interior.

Each of the amplifiers 4a to 4d is connected via an inverse filter network 5 to a recording device 2 such as a tape recorder as acoustic information recording means for recording acoustic information by a binaural recording method. The method of recording the acoustic information in the recording device 2 is the same as in the case of the conventional sound reproducing device described above, and the configuration shown in FIG. 17 is applied as it is.

On the other hand, the contents of the inverse filter network 5 are as follows because the sound reproducing device 1 has four speakers 3a to 3d and _two occupants L ₁ and L ₂ as listeners. To construct. That is, first, as shown in FIG. 2, the test signal generator 6 is connected to the amplifiers 4a to 4d, and the reproduced sound S corresponding to the test signal is output from the speakers 3a to 3d.
_{1 to} S ₄ are generated, reproduced sounds S _{1 to} S ₄ and sounds M _{1 to} M ₄ measured at the binaural positions of the dummy heads D ₁ and D _2.
Based on the following, the number of speakers × the number of occupants × 2 (4 × 2 × 2 = 16 in this embodiment) existent speakers 3a.
~ 3d and the acoustic transfer characteristics h between the ears of the occupants L ₁ and L _2
11 to identify the ~h _44.

Using these acoustic transfer characteristics h _{11 to} h ₄₄ , the sounds M _{1 to} M ₄ measured at the binaural positions are expressed by the following equation (6).

[0029]

[Equation 6]

(6) On the other hand, the target effect of the configuration of this embodiment is

[0031]

[Equation 7]

It is (7). Therefore, if this equation (7) is transformed,

[0033]

[Equation 8]

(8) Therefore, if the reproduced sounds S _{1 to} S ₄ are represented by the following equation (9) from the above equations (6) and (8), the above equation (7) is satisfied.

[0035]

[Equation 9]

(9) Therefore, the inverse filter network 5 in the present embodiment
Should be constructed so as to satisfy the following expression (10).

[0037]

[Equation 10]

(10) Then, the inverse filter network 5 integrates the recorded sounds B ₁ and B ₂ as inputs and the speakers 3a to 3d of the supply destination as shown in FIG. It becomes a shape. Each element constituting the inverse filter network 5 in this example | H |, H ₁₁ ~H ₄₄ is as follows.

[0039]

[Equation 11]

[0040]

[Equation 12]

[0041]

[Equation 13]

With such a structure, the occupant L
Sounds M ₁ and M _{3 at} the left ear positions of ₁ and L ₂ respectively
Corresponds to the sound B ₁ recorded on the left ear side that is binaurally recorded in the recording device 2, and the sounds M ₂ and M _{4 at} the right ear positions of the occupants L ₁ and L ₂ are binaurally recorded in the recording device 2. Since it matches the recorded sound B ₂ on the right ear side, each of the plurality of occupants L ₁ and L ₂ plays the music with the same spread as in the original sound field such as the concert hall in the vehicle interior. You can enjoy.

Since the impulse response always converges to zero within a finite time and has no pole other than the origin, in consideration of system stability, the FIR filter is generally used as the control filter. Is applied. But,
Since the frequency characteristic of the sound pressure level in the vehicle interior of the vehicle has sharp peaks and valleys as shown in FIG. 3 (a) due to air column resonance, FIR where the peak portion is dull as shown in FIG. 3 (b) When the inverse filter network 5 is formed by the filters, FIG.
As shown in (c), crosstalk cannot be completely canceled.

On the other hand, in the IIR filter, as shown in FIG.
As shown in FIG. 3D, the peaks and valleys do not become dull, so that it is possible to completely cancel the crosstalk and obtain a flat characteristic as shown in FIG. That is, in the sound reproducing device 1 applied to the interior of the vehicle as in the present embodiment, it is desirable that the inverse filter network 5 is formed by the IIR filter instead of the FIR filter.

FIGS. 4 and 5 are views showing a second embodiment of the present invention. In this embodiment as well, as in the first embodiment, the sound reproducing device 1 according to the present invention is installed in the front seat of a vehicle. It has been applied to. The same components as those in the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted. That is, in this embodiment, although the basic configuration is the same as the first embodiment, and its impact on the occupant L ₁ farthest speaker 3d from the passenger L _1, furthest from the occupant L ₂ speakers It is considered that the influence of 3a on the occupant L ₂ is negligibly small, and as shown in FIG. 5, the acoustic transfer characteristics h ₄₁ , relating to the negligibly small influences,
It is considered that h ₃₁ , h ₂₄ and h ₁₄ are omitted.

Therefore, in this embodiment, (the number of speakers-1) x the number of passengers x 2 (in this example, 3 x 2 x 2 = 12).
Sound transmission characteristics h _{11 to} h ₄₄ are used, and thus the sounds M _{1 to} M ₄ measured at the binaural positions are used.
Is expressed as the following equation (11).

[0047]

[Equation 14]

(11) The equation (11) corresponds to the equation (6) in the first embodiment. Therefore, the inverse filter network 5 in the present embodiment is the same as that in the first embodiment. Can be obtained as shown in FIG. However, since the number of acoustic transfer characteristic used as described above is smaller than the first embodiment, the elements constituting the inverse filter network _{5 | H | ', H 11} ' ~H 44 ' is as follows become.

[0049]

[Equation 15]

[0050]

[Equation 16]

[0051]

[Equation 17]

As described above, according to the configuration of this embodiment, the elements | H | 'and H constituting the inverse filter network 5
_{Since 11} ′ to H ₄₄ ′ are simplified as compared with the first embodiment, it is possible to achieve the same effect as that of the first embodiment with a smaller calculation load, and also to reduce the cost. To be That is, it is possible to provide the more practical sound reproducing device 1.

FIGS. 6 and 7 are views showing a third embodiment of the present invention. In this embodiment as well, as in the first embodiment, the sound reproducing device 1 according to the present invention is installed in the front seat of a vehicle. It has been applied to. The same components as those in the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted. That is, even in the present embodiment, the basic configuration is the same as that of the first embodiment, but the influence of the two loudspeakers that are respectively close to the occupants L ₁ and L ₂ is the greatest, and It is considered that the influences of the speakers other than the above can be ignored, and as shown in FIG. 7, the acoustic transfer characteristics h ₃₁ , h ₄₁ , h ₃₂ , h ₄₂ , h ₁₃ ,
It believes omitted the _{h 23, h 14, h 24} .

In other words, in the present embodiment, the number of loudspeakers (2) × the number of passengers × 2 (2 × 2 in this example)
The sound transfer characteristics h _{11 to} h _{44 of} (× 2 = 8) will be used, and the sound M ₁ measured at the binaural position by these will be used.
~ M ₄ is expressed as the following equation (12).

[0055]

[Equation 18]

(12) The expression (12) corresponds to the expression (6) in the first embodiment. Therefore, the inverse filter network 5 in the present embodiment is similar to that in the first embodiment. Can be obtained as shown in FIG. However, since the number of acoustic transfer characteristics used as described above is smaller than that in the first embodiment, each element | H | ″, H ₁₁ ″ to H ₄₄ ″ forming the inverse filter network 5 is It becomes as follows.

[0057]

[Formula 19]

[0058]

[Equation 20]

As described above, according to the configuration of this embodiment, each element | H | ″, H constituting the inverse filter network 5 is
_{For 11} '' _{~H 44} '' it is further simplified as compared with the second embodiment, the first embodiment and the same effect is achieved by computational load even less than the second embodiment be able to. That is, a more practical sound reproduction device 1
Can be provided.

In particular, the configuration of the present embodiment is suitable for the case where the influence of the two adjacent speakers is remarkably large, for example, when the sound is reproduced in the front seat and the rear seat of the vehicle. FIG. 8 is a diagram showing a fourth embodiment of the present invention, and this embodiment also applies the sound reproducing device 1 according to the present invention to a front seat of a vehicle, as in the first embodiment. . The same components as those in the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted.

That is, in the present embodiment, for example, the acoustic spaces around the _two occupants L ₁ and L ₂ who are on the front seats of the vehicle are in a symmetrical relationship, that is, the left ear of the occupant L ₁ and the occupant L 2. ₂
Are in the same condition as the right ear of the passenger L ₁ , and the right ear of the passenger L ₁ and the passenger L _1
This is based on the assumption that the left ear of ₂ is in the same condition and that the influence of the speaker farthest from the occupants L ₁ and L ₂ can be ignored.

Then, an inverse filter network 5 similar to the conventional one-person sound reproducing apparatus described with reference to FIGS. 16 to 18 is used, and three speakers 3a, 3b and 3c are provided to the left and right in front of the occupant L _1. 3a, speaker 3b in front left and right 3b is aligned and the occupant L _2, 3c are arranged so as to be arranged, furthermore, a speaker 3a, 3 on the edge
The amplifiers 4a and 4c driving c are supplied with one output (conventional left ear side) filtered by the inverse filter network 5, and the amplifier 4b driving the speaker 3b located at the center is supplied with the inverse filter network 5 The other (conventional right ear side) output filtered by is supplied.

With this structure, the inverse filter network 5 for one person and the three speakers 3a to 3c allow the two occupants L ₁ and L ₂ to be in the original sound field such as a concert hall. You can listen to music with the same spread as. That is, it is possible to provide the sound reproducing device 1 for a plurality of people with an extremely simple configuration. 9 and 10 are views showing a fifth embodiment of the present invention.

In the first to fourth embodiments, the contents of the inverse filter network 5 are not changed. However, especially in a closed space such as the passenger compartment, the acoustic transfer characteristic h ₁₁ to h ₄₄ are temperature, number of passengers, because it can vary greatly depending on the opening and closing status of the window, even if inverse filter network 5 works well in certain circumstances, that good act in other situations There is no guarantee.

Therefore, in this embodiment, the controller 10 including the inverse filter network 5 is interposed between the recording device 2 and the amplifiers 4a and 4b, and in the controller 10, in addition to the inverse filter network 5, ,
The test signal generator 6, the changeover switch 11 for selecting the output of the inverse filter network 5 and the output of the test signal generator 6 and supplying them to the amplifiers 4a and 4b, and the output of the test signal generator 6 and the occupant L ₁ . The acoustic transfer characteristics between the ears of the speakers 3a and 3b and the occupant L ₁ are identified based on the outputs of the microphones MP ₁ and MP ₂ arranged at the ear position, and further, the inverse filter network 5 of the inverse filter network 5 is matched to the identification result. The identification calculation part 12 which changes the content is provided.

In this embodiment, the test signal generator 6, the changeover switch 11 and the identification calculation section 12 are activated by the changeover signal input by the operation of the occupant L ₁ , and the contents of the inverse filter network 5 are changed. It is supposed to be updated. As a concrete calculation method of the acoustic transfer characteristic in the identification calculation unit 12, a method using FFT, a method using an adaptive filter such as an LMS algorithm, or the like can be considered.

For example, as a method using the FFT, a random signal such as white noise is generated as a test signal, and the test signal and the measurement sound measured by the microphones MP ₁ and MP ₂ are Fourier transformed by FFT to obtain each frequency component. The transfer function is calculated by obtaining the attenuation state for each, the Fourier transform of the transfer function is performed to obtain the impulse response function, the acoustic transfer characteristics are calculated, and the content of the inverse filter network 5 is updated according to the result. .

The outline of the method using the LMS algorithm is as follows. That is, the test signal is x
(N), the measurement sound of the l-th microphone when a test signal is generated from the m-th speaker is e _l (n),
Let C be the filter coefficient corresponding to the j-th transfer function C _lm between the m-th speaker and the l-th microphone.
^ _Lmj , the output of the adaptive filter during updating of the filter coefficient is y
(N) Is established. Next, when the evaluation function Je and the square of the difference between the output of the adaptive filter and the microphone of the measuring _{sound, Je = {e l (n} ) -y (n)} 2 = {e l (n) -ΣC ^ lmj x (n−j)} ² (14), and the filter coefficient C ^ _lmj is updated with a value obtained by _performing partial differentiation of this evaluation function Je with respect to each filter coefficient C ^ _lmj .

[0069] Therefore, the above (14) from equation _{∂Je / ∂C ^ lmj = -2x (} n-j) {e l (n) -ΣC ^ lmj x (n-j)} ...... (15) Therefore, the rewriting formula of the filter coefficient is as follows (16)
It becomes like a formula.

[0070] _{C ^ lmj (n + 1)} = C ^ lmj (n) + αx (n-j) {e l (n) -ΣC ^ lmj x (n-j)} ...... (16) In addition, alpha convergence coefficient Is a coefficient that is related to the speed at which the filter converges optimally and its stability.

FIG. 10 is a flow chart showing the outline of the processing of the characteristic portion of this embodiment. The operation of this embodiment will be described below with reference to FIG. That is, first, the step 101
In step 102, it is determined whether or not the switching signal is input. If it is determined that the switching signal is not input, it is determined that the contents of the inverse filter network 5 do not need to be changed, and step 102 and subsequent steps are performed. Is not executed.

However, if it is determined in step 101 that the switching signal is input, the process proceeds to step 102, in which the changeover switch 11 is switched to the test signal generator 6.
The test signal generator 6 generates a test signal and outputs the test signal. Then, a test sound corresponding to the test signal is generated from the speakers 3a and 3b, and the test sound is generated by the microphone MP ₁ ,
Measured by MP ₂ .

Then, in step 104, the measurement results of the microphones MP ₁ and MP ₂ are read, and in step 105, the identification calculation section 12 causes the microphone M to read.
The transfer function is identified by the method described above based on the measurement results of P ₁ and MP ₂ and the test signal. When such a transfer function is identified, the process proceeds to step 106, and the content of the inverse filter network 5 is appropriately updated according to the new transfer function.

As described above, according to the configuration of this embodiment, the speakers 3a and 3b and the occupant L ₁ respond to the request from the occupant L _1.
Since the transfer function between the two ears of ₁ is identified and the contents of the inverse filter network 5 are updated according to the transfer function, the acoustic transfer characteristic is greatly changed according to the temperature, the number of passengers, the opening / closing state of windows, and the like. Even if there is a change, it is possible to obtain good operational effects as the sound reproducing device 1.

FIG. 11 is a diagram showing a sixth embodiment of the present invention. That is, the basic configuration of the present embodiment is the same as that of the fifth embodiment described above, and the difference is that the acoustic transfer characteristics are obtained in response to a request from an occupant in the fifth embodiment. In this embodiment, it is determined whether or not the acoustic transfer characteristic has changed, and if it is determined that the acoustic transfer characteristic has changed, the acoustic transfer characteristic is obtained and the inverse filter network is updated.

That is, for example, the acoustic transfer characteristics in the vehicle compartment are
A temperature sensor that detects the temperature in the passenger compartment because it changes depending on the temperature, the opening / closing status of windows, the number of passengers, the positions of passengers, etc.
A window opening / closing position sensor that detects the opening / closing state of the window, a seat switch that detects the presence or absence of an occupant, a seat position sensor that detects the position of the seat, and the like are provided, and the detection values of these sensors are read in step 110 of FIG. In step 111, it is determined whether or not the acoustic transfer characteristics have changed based on the detection values of those sensors. Then, if it is determined in step 111 that the acoustic transfer characteristics have changed, the processing from step 102 onward is executed.

With such a structure, it is possible to obtain the same operational effect as that of the fifth embodiment without bothering the occupant's hand. 12 and 13 are views showing a seventh embodiment of the present invention. That is, in this embodiment, the controller 10
A temperature table, a window opening / closing position sensor, a seat switch, a seat position sensor, and a memory table 13 that stores therein the relationship among temperature, the opening / closing state of windows, the number of occupants, the positions of occupants, etc. and each element of the inverse filter network 5. And a filter selection unit 14 that selects the optimum filter stored in the storage table 13 according to the sensor detection values supplied from the above.

Then, as shown in FIG. 13, step 1
The detection value of the sensor is read at 10, then step 11
The process proceeds to step 1 to determine whether or not the acoustic transfer characteristics have changed based on the detection values of those sensors. If it is determined in step 111 that the acoustic transfer characteristics have changed, the process proceeds to step 112. , The value of the filter corresponding to the sensor detection value is selected, and the content of the inverse filter network 5 is updated with this selected value.

In other words, with the configuration of this embodiment, the sound reproducing device 1 can be used even if the sound transfer characteristics greatly change depending on the temperature, the number of passengers, the opening / closing state of the windows, etc., as in the fifth embodiment. As a result, there is an advantage that the test signal is not heard by the occupant L ₁ and the identification calculation is not necessary because the test sound does not have to be generated.

The storage table 13 is stored in an exchangeable IC card or the like, that is, a so-called entry system, and the contents of the storage table 13 stored in the IC card are set for each owner of the IC card. By doing so, the acoustic transfer characteristics that differ depending on the physique of each occupant can be accurately reproduced, more accurate localization of the sound field can be achieved, and more realistic music can be enjoyed and noise can be evaluated.

14 and 15 are views showing the eighth embodiment of the present invention. That is, the basic configuration is the same as that of the seventh embodiment, but in this embodiment, the storage table 15 stores the filter coefficient change amount with respect to the change amount of the sensor detection value, and the filter coefficient update is performed. The unit 16 reads the filter coefficient change amount from the storage table 15 based on the sensor detection value, updates the current filter in accordance with the read change amount, and sets it as a new filter, which is set in the inverse filter network 5. It is a thing.

That is, as shown in FIG. 15, step 1
When it is determined in 11 that the acoustic transfer characteristics have changed, the process proceeds to step 114, the filter change amount stored in the storage table 15 is read based on the change amount of the sensor detection value, and then step 115 is performed. Then, the current value of the inverse filter network 5 is read out, and then the process proceeds to step 116 and steps 114 and 11 are executed.
The value read in 5 is added to obtain a new value of the inverse filter network 5, and this is updated.

With such a configuration, since the filter change amount is obtained according to the change amount of the situation, it is possible to set the filter more finely than in the seventh embodiment, and to obtain a more realistic sound field. It becomes possible to perform localization. In the configuration of this embodiment, the contents of the storage table 15 may be stored in an IC card or the like to form an entry system.

In each of the above embodiments, the case where the sound reproducing device 1 according to the present invention is applied to the vehicle interior has been described, but the sound reproducing space to which the present invention is applicable is not limited to this. Further, in each of the above-mentioned embodiments, the case where the number of passengers as listeners is two has been described, but the present invention can be applied even if the number of listeners is three or more.

[0085]

As described above, according to the present invention,
Since an inverse filter network was constructed to eliminate crosstalk for multiple listeners and the acoustic information recorded by the binaural recording method was processed by the inverse filter network before being supplied to the acoustic generation means, Each of the listeners can enjoy music having the same expanse in the reproduced sound field as if they were in the original sound field of a concert hall or the like, and can effectively evaluate noise.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a method of measuring an acoustic transfer characteristic in the first embodiment.

FIG. 3 is a frequency characteristic diagram illustrating characteristics of a filter format.

FIG. 4 is a block diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 5 is a diagram showing a method of measuring acoustic transfer characteristics in the second embodiment.

FIG. 6 is a block diagram showing a configuration of a third exemplary embodiment of the present invention.

FIG. 7 is a diagram showing a method of measuring an acoustic transfer characteristic in the third embodiment.

FIG. 8 is a block diagram showing a configuration of a fourth exemplary embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of a fifth exemplary embodiment of the present invention.

FIG. 10 is a flowchart showing an outline of processing of a characteristic part in the fifth embodiment.

FIG. 11 is a flowchart showing an outline of processing of a characteristic part in the sixth embodiment.

FIG. 12 is a block diagram showing a configuration of a seventh exemplary embodiment of the present invention.

FIG. 13 is a flowchart showing an outline of processing of a characteristic portion in the seventh embodiment.

FIG. 14 is a block diagram showing the configuration of an eighth embodiment of the present invention.

FIG. 15 is a flowchart showing an outline of processing of a characteristic part in the eighth embodiment.

FIG. 16 is a block diagram showing a configuration of a conventional sound reproducing device.

FIG. 17 is an explanatory diagram of a binaural recording method.

FIG. 18 is a diagram showing a conventional method of measuring acoustic transfer characteristics.

[Explanation of symbols]

1 sound reproducing apparatus 2 recording device (audio information recording means) 3 a to 3 d speaker 4a~4d amplifier 5 inverse filter network h ₁₁ to h ₄₄ acoustic transfer characteristic L _1, L ₂ occupant (listeners)

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[Procedure amendment]

[Submission date] January 25, 1993

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[Equation 11]

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[Equation 12]

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[Equation 13]

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[Equation 15]

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[Equation 16]

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[Equation 17]

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[Formula 19]

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[Equation 20]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mina Kiyoshi, 2 Takara-cho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd.

Claims (3)

[Claims] 1. A sound information recording means for recording sound information by a binaural recording system, N (N ≧ 2) sound generating means, and between the sound information recording means and the N sound generating means. Based on the n × 2 × N acoustic transfer characteristics between the two ears of n (n ≧ 2) listeners and the N acoustic generators, the acoustic generators and the listeners are interposed. And an inverse filter network constructed so as to eliminate crosstalk between them. 2. A sound information recording means for recording sound information by a binaural recording method, N (N ≧ 3) sound generating means, and between the sound information recording means and the N sound generating means. Between the two ears of n listeners (n ≧ 2) and (N-1) sound generating means excluding the sound generating means farthest from each listener among the N sound generating means. And an inverse filter network constructed so as to eliminate crosstalk between the sound generating means and the listener based on n × 2 × (N−1) sound transfer characteristics between them. Sound reproduction device. 3. A sound information recording means for recording sound information by a binaural recording method, N (N ≧ 3) sound generating means, and between the sound information recording means and the N sound generating means. N × 2 × 2 sound between the two ears of n (n ≧ 2) listeners and two sound generators among the N sound generators that are close to each listener. A sound reproducing device, comprising: an inverse filter network constructed so as to eliminate crosstalk between the sound generating means and a listener based on transfer characteristics.