JPH07212890A - Automatically correcting system for sound field inside vehicle - Google Patents

Abstract

PURPOSE:To output more preferable sound for better accoustic feeling by optimally performing an automatic correction of sound field inside a vehicle by using at least two microphones. CONSTITUTION:M-series signals are generated from each speaker 1 and 2 by an M-series signal generation means 5, the signals are received by each microphone 3 and 4, they are fed back to a speaker sound volume level setting means 10 via a sound fetching means 6, and the volume level of each speaker 1 and 2 is corrected. The signal of each microphone 3 and 4 is imparted to a frequency characteristic analysis means 8 via the sound fetching means 6 and an impulse response signal restoration means 7, frequency characteristics are analyzed, and an equalizer coefficient is set by an equalizer coefficient setting means 9. The output signal of the impulse response signal restoration means 7 is received and the delay time of the output of sound from each speaker 1 and 2 is set by a speaker delay time setting means 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle interior sound field automatic correction system for automatically correcting a sound field formed by an audio system installed in a vehicle compartment.

[0002]

2. Description of the Related Art A stereo audio system mounted on a vehicle such as a passenger car is equipped with at least two speakers and receives a stereo broadcast reception wave such as a radio receiver, a magnetic tape reproducing device or a compact disc (C).
D) A signal from a reproducing device or the like is used as a sound source, and a sound for stereo reproduction is output. For example, in an audio system having two speakers, one speaker is generally arranged as a left speaker inside a front left door, and the other speaker is arranged as a right speaker inside a front right door. . With such a speaker arrangement, the left speaker outputs the left channel sound of the stereo reproduced sound, and the right speaker outputs the right channel sound of the stereo reproduced sound.

[0003]

A typical stereo system has a pair of speakers equidistantly in front of the listener.
Moreover, it is arranged at a predetermined angle (for example, 60 °) with respect to the listener, and the recorded source is also made on the premise. On the other hand, in the vehicle, the distance between the speakers is different on the left and right, and the stereo effect cannot be fully utilized as it is.

Therefore, even in passenger compartments such as passenger cars,
There is known a vehicle interior sound field correction system that automatically corrects the sound field in the vehicle interior in order to realize a sense of presence and a sense of spaciousness.
Using one microphone and one microphone extended to the vicinity of the listening position, the sound field in the vehicle compartment was corrected based on the audio signals collected by this microphone. For example, as shown in FIG. 12, one microphone 31 is placed in the vicinity of the listener's head 24 in the vehicle compartment, and the microphone 31 receives audio output from the left speaker 1 and the right speaker 2 to generate an electric signal in the vehicle interior sound. Send to the automatic field correction system, perform the prescribed processing,
The sound field in the passenger compartment is corrected by adjusting the volume of the left speaker 1 and the right speaker 2.

However, since such a correction cannot make a measurement including the head-related transfer function until the sounds from the left and right speakers 1 and 2 actually reach the listener's ears, there is a difference in correspondence with the sense of hearing. It is easy to make an error in the measurement of the arrival time of the sound from the left and right speakers 1 and 2 to the listening position, and there is a case where one microphone happens to measure the interference point of the frequency characteristic. Therefore, there is a problem that it is difficult to optimally correct the vehicle interior sound field.

The present invention has been made to solve the above problems, and by using at least two microphones, the sound field in the passenger compartment is automatically and optimally corrected, and a preferable sound more audible is obtained. It is an object of the present invention to provide a vehicle interior sound field automatic correction system capable of outputting the.

[0007]

In order to achieve the above object, a vehicle interior sound field automatic correction system (1) according to the present invention comprises:
An automatic vehicle interior sound field correction system for automatically correcting a sound field formed by an audio system installed in a vehicle interior, wherein a test signal is generated and voiced by a plurality of speakers of the audio system. A test signal generating means, a voice capturing means for capturing as a voice signal a test response signal collected by a plurality of microphones placed at the listening position in the vehicle interior, and the output signals of the voice capturing means Speaker volume level setting means for setting the volume level of the speaker, impulse response signal restoring means for restoring the test response signal captured by the voice capturing means as an impulse response signal, and the impulse response signal restoring means The frequency response of the impulse response signal is analyzed by Fast Fourier Transform to analyze the frequency characteristics of the impulse response signal. Number characteristic analysis means, equalizer coefficient setting means for setting an equalizer coefficient for correcting the frequency characteristics, and an impulse response signal output from the impulse response signal restoring means based on the impulse response signal from each speaker to each microphone. Speaker delay time setting means for calculating the arrival time of the sound and setting the delay time of the sound output from each speaker based on the arrival time.

Further, the vehicle interior sound field automatic correction system (2) according to the present invention is the same as the vehicle interior sound field automatic correction system (1), wherein the plurality of microphones are both ears of a person sitting on a seat in the vehicle compartment. It is characterized by being attached to.

Further, in the vehicle interior sound field automatic correction system (3) according to the present invention, in the vehicle interior sound field automatic correction system (1), the plurality of microphones are attached to a headrest of a seat in the vehicle compartment. It has a feature.

Further, in the vehicle interior sound field automatic correction system (4) according to the present invention, a soundproof material is attached to the ear hole sides of the plurality of microphones in the vehicle interior sound field correction system (2). It is characterized by being.

Further, the vehicle interior sound field automatic correction system (5) according to the present invention is characterized in that in the vehicle interior sound field automatic correction system (3), the headrest has a microphone insertion portion into which the microphone can be inserted. It has a feature.

The vehicle interior sound field automatic correction system (6) according to the present invention is characterized in that, in the vehicle interior sound field automatic correction system (3), the microphone is provided with a mounting means to a headrest. .

[0013]

[Operation] Automatic vehicle interior sound field correction system (1) having the above configuration
According to the above, the test signal generating means generates the M-series signal, the speaker converts it into voice, and the voice capturing means captures the M-series response signal collected by the microphone as a voice signal. The speaker volume level setting means sets the volume level of each speaker based on the captured audio signal, and the impulse response signal restoring means converts the M-series response signal captured by the audio capturing means into an impulse response signal. Will be restored as. In the frequency characteristic analyzing means, the restored impulse response signal is subjected to fast Fourier transform, the frequency characteristic of the impulse response signal is analyzed, and in the equalizer coefficient setting means, an equalizer coefficient for correcting the frequency characteristic is set. . The speaker delay time setting means sets the delay time of the sound output from each speaker based on the arrival time of the sound from each speaker to each microphone calculated based on the impulse response signal.

Further, according to the vehicle interior sound field automatic correction system (2) having the above-mentioned configuration, each microphone is attached to both ears of the person sitting in the seat in the vehicle compartment, and the sound input to each microphone is A head-related transfer function is also included, and it is possible to input a voice that is close to the actual sensation.

Further, according to the vehicle interior sound field automatic correction system (3) having the above-mentioned structure, each microphone is attached to the headrest, whereby the microphone is attached to both ears of the person sitting in the seat in the vehicle interior. A state similar to that of is realized, and humans do not hear annoying test sounds.

According to the vehicle interior sound field automatic correction system (4) having the above-mentioned configuration, the test voice is input to each microphone, but the soundproof material attached to each microphone causes the sound to reach both human ears. Will reduce the input level.

Further, according to the vehicle interior sound field automatic correction system (5) having the above structure, the microphone is inserted into the microphone insertion portion of the headrest, and the microphone can be easily attached to the headless.

According to the vehicle interior sound field automatic correction system (6) having the above-mentioned structure, each of the microphones is attached to the headrest through the attaching means, and the microphone can be easily attached to the headrest. .

[0019]

【Example】

[First Embodiment] FIG. 1 is a block diagram showing an automatic vehicle interior sound field correction system according to a first embodiment of the present invention. In FIG. 1, reference numeral 5 is an M-sequence signal generating means (test signal generating means) for generating an M-sequence signal as a test signal and converting the M-sequence signal into a voice by the left speaker 1 and the right speaker 2 of the audio system, and 6 is a vehicle interior. A voice capturing means for capturing an M-sequence response signal (test response signal), which is a response of the M-sequence signal collected by the left microphone 3 and the right microphone 4 placed at the listening position, as a voice signal, and 10 is voice capture. The speaker volume level setting means for analyzing the volume level corresponding to each speaker 1, 2 by the output signal of the means 6 and setting the volume level of each speaker 1, 2 based on the analysis result is shown. Reference numeral 7 denotes an impulse response signal restoring means which is connected to the voice capturing means 6 and restores the M-sequence response signal captured by the voice capturing means 6 as an impulse response signal. The impulse response signal restoring means 7 has a frequency characteristic analysis. The means 8 and the speaker delay time setting means 11 are connected, and the frequency characteristic analyzing means 8 analyzes the frequency characteristic of the impulse response signal by performing a fast Fourier transform (FFT) on the impulse response signal restored by the impulse response signal restoring means 7. To do. An equalizer coefficient setting means 9 is connected to the frequency characteristic analyzing means 8, and the equalizer coefficient setting means 9 has at least a center frequency for correcting characteristic peaks and dips of the frequency characteristic,
Set equalizer coefficients including sharpness and gain. The speaker delay time setting means 11 calculates the arrival time of the sound from each speaker 1, 2 to each microphone 3, 4 based on the impulse response signal output from the impulse response signal restoring means 7, and calculates the calculated sound The delay time of the sound output from each speaker 1 and 2 is set based on the arrival time.

FIG. 2 is a block diagram showing the hardware configuration of an audio system equipped with the vehicle interior sound field automatic correction system according to the first embodiment. In FIG. 2, reference numeral 5 denotes M-sequence signal generating means, and this M-sequence signal generating means 5 is connected to a terminal 13a of the audio system main body 13. When the sound field correction is completed, a CD reproducing device or the like for reproducing a digitized audio signal from a CD (compacted disc) on which a normal music performance or the like is recorded is connected to the terminal 13a. The audio system main body 13 includes a microcomputer 14 having various means in the vehicle interior sound field automatic correction system described with reference to FIG. 1, a digital signal processor (hereinafter referred to as DSP) 15, and analog / digital (A / D) conversion. The device 32, the amplifier 34, and the digital / analog (D / A) converter 33 are provided. The input end of the amplifier 34 is connected to each of the microphones 3 and 4, and the output end thereof is connected to the analog / digital (A / D) converter 32. Digital / analog (D / A) converter 3
The output terminal of 3 is an amplifier 16 to which the speakers 1 and 2 are connected.
It is connected to the. CD playback device 1 for the DSP 15
2, the A / D converter 32, the D / A converter 33, and the microcomputer 14 are connected.

FIG. 3 is a plan sectional view of a passenger car equipped with the audio system shown in FIG. In FIG. 3, in the passenger compartment 17 of the passenger car 17, the left speaker 1 and the right speaker 2 are attached to the front left door 18 and the front right door 19, respectively. Reference numeral 20 denotes a passenger seat having a headrest 22, and 21 denotes a driver's seat having a headrest 23. Reference numeral 24 denotes a head of a driver (listener) sitting in the driver's seat 21. The left microphone 3 is attached to the left ear of the driver, and the right microphone 4 is attached to the right ear.

Next, the operation of the vehicle interior sound field automatic correction system according to this embodiment will be described with reference to FIGS. 1, 2, and 3. First, an M-sequence signal is generated from the M-sequence signal generation means 5 and transmitted to the left speaker 1 and the right speaker 2. As a result, a sound corresponding to the M-sequence signal is output from each of the speakers 1 and 2, and the sound is collected by the left microphone 3 and the right microphone 4 and converted into an electric signal. The converted electric signal is an M-series response signal which is a response of the M-series signal, and the M-series response signal is input to the audio capturing means 6 as an audio signal. The output signal from the voice capturing means 6 is input to the speaker volume level setting means 10 and the impulse response signal restoring means 7. The speaker volume level setting means 10 analyzes the volume level corresponding to each of the speakers 1 and 2 by the output signal of the voice capturing means 6, and sets the volume level of each of the speakers 1 and 2 based on the analysis result. Therefore, for example, the left speaker 1 of the driver (listener) in the passenger car 17
Even if the distance between the right speaker 2 and the right speaker 2 is different, the volume level of the left speaker 1 is set higher than the volume level of the right speaker 2, and the sound of the same volume level can be heard with both ears.

Further, the impulse response signal restoring means 7 restores the M-sequence response signal taken in by the voice taking means 6 as an impulse response signal and inputs it to the frequency characteristic analyzing means 8. In the frequency characteristic analysis means 8, the restored impulse response signal is subjected to fast Fourier transform, the frequency characteristic of the impulse response signal is analyzed, and in the next equalizer coefficient setting means 9, the characteristic peak of the frequency characteristic and Equalizer coefficients including at least the center frequency, the sharpness and the gain for correcting the dip are set. Therefore, for example, the equalizer in the DSP 15 of FIG. 2 is corrected by this equalizer coefficient. That is, the right-channel speaker 2 is optimally corrected by the right-channel equalizer, and the left-channel speaker 1 is optimally corrected by the left-channel equalizer in terms of high-frequency, mid-range, and low-frequency characteristics.

The speaker delay time setting means 11 calculates the arrival time of the voice from each speaker 1, 2 to each microphone 3, 4 based on the impulse response signal output from the impulse response signal restoring means 7, The delay time of the sound output from each speaker 1 and 2 is set based on the calculated arrival time of the sound. Therefore, by using this delay time, even if the distance between the left speaker 1 and the right speaker 2 with respect to the driver in the vehicle compartment is not the same, the sounds from the speakers 1 and 2 are simultaneously input to both ears of the driver. It will be. That is, even if the left speaker 1 is farther from the driver than the right speaker 2, the audio output from the right speaker 2 is delayed more than the audio output from the left speaker 1 due to the setting of the delay time, The sounds from the speakers 1 and 2 are simultaneously input to both ears.

After the processing described above is completed, when the CD reproducing device is connected to the terminal 13d instead of the M-sequence signal generating means 5 and the CD reproducing device is turned on, a digital audio signal such as music performance is input to the DSP 15. Digitally processed. Thereafter, the digitally converted digital audio signal is converted into an analog signal by the DA converter 33, further amplified by the amplifier 16, converted into audio by the speakers 1 and 2, and output. The audio output of these speakers 1 and 2 is as shown in FIG.
Since the correction process described in 1) is performed, the driver in the vehicle compartment can listen to a music performance in an optimal sound field.

Although the M-sequence signal is used as the test signal in the first embodiment, the invention is not limited to this. In another embodiment, the correction accuracy is lower than that when the M-sequence signal is used. It is also possible to use signals, white noise, pink noise, band noise, and the like.

In the first embodiment, the audio system to which the CD reproducing device is connected has been described, but the present invention is not limited to this, and an audio system to which a magnetic tape reproducing device or the like is connected may be used. Further, in the above-described first embodiment, two speakers are used.
Although the case where the number of speakers is one is described, the number of speakers is not limited to two, and four speakers may be provided in another embodiment. In this case, the same processing can be performed to obtain the same effect.

[Embodiment 2] FIG. 4 is a perspective view showing the structure of a microphone according to Embodiment 2 of the present invention. In FIG.
Reference numeral 24 denotes a human head, and 25 denotes an ear hole. A soundproof material 26 such as rubber or sponge is attached to the ear hole 25 side of the microphone 41. Such a microphone 41
By inserting the sound into the listener's ear, the listener does not need to hear the noise of the noisy test signal during the sound field correction.

[Third Embodiment] FIG. 5 is a perspective view showing the structure of a microphone according to a third embodiment of the present invention. In FIG.
A soundproof material 27 such as a rubber ring is attached to the ear hole side of the microphone 42. By inserting the microphone 42 into the listener's ear, the listener does not need to hear the noise of the noisy test signal.

[Fourth Embodiment] FIG. 6 is a front view showing a state in which a microphone according to a fourth embodiment of the present invention is attached to a headrest of a seat, and FIG. 7 is a side view showing a state in which the headrest is viewed from the side. Is. In FIGS. 6 and 7, for example, the microphone insertion portion 2 is provided on the headrest 23 of the driver's seat 21
8 and 28 are provided, and this microphone insertion portion 2
Microphones 3 and 4 are plugged into 8 and 28. This makes it possible to realize a state substantially similar to the case where the microphones 3 and 4 are inserted into both ears of the person sitting in the driver's seat 21, and it is not necessary for the person to hear the jarring test sound.

[Fifth Embodiment] FIG. 8 is a front view showing a state in which a microphone according to a fifth embodiment of the present invention is attached to a headrest of a seat, and FIG. 9 is a side view showing the headrest viewed from the side. It is a figure. In FIGS. 8 and 9, each of the microphones 3 and 4 is provided with a microphone hook 29 as a means for attaching to the headrest 23. As a result, the microphones 3 and 4 are attached to the headrest 23 as shown in FIG. 9, and the same effect as that of the fourth embodiment can be obtained.

[Sixth Embodiment] FIG. 10 is a front view showing a state in which a microphone according to a sixth embodiment of the present invention is attached to a headrest of a seat, and FIG. 11 is a side view showing a state in which the headrest is viewed from the side. It is a figure. 10 and 11, each of the microphones 3 and 4 has a rubber band 30 as a means for attaching to the headrest 23. As a result, the microphones 3 and 4 are attached to the headrest 23 as shown in FIG. 10, and the same effect as that of the fourth embodiment can be obtained. In addition, in the above Examples 4, 5, and 6, the rubber band 3 is used.
Although the microphone is attached to the headrest by 0 or the like, in another embodiment, the microphone may be attached to the headrest using a velcro or a double-sided adhesive tape.

[0033]

As described above, according to the vehicle interior sound field automatic correction system (1) of the present invention, the sound output from a plurality of speakers in the vehicle interior is corrected for volume balance, high sound, and middle sound. The frequency characteristics of bass, the delay time, and the like are accurately corrected, whereby the sound field in the vehicle interior is automatically and optimally corrected, and a more preferable sound can be output as a feeling of hearing.

Further, according to the vehicle interior sound field correction system (2) of the present invention, the plurality of microphones are attached to both ears of the person sitting in the seat in the vehicle compartment, whereby the sound field correction is performed. The test signal generated sometimes can be accurately received and fed back to both ears of the listener, and therefore the automatic correction of the sound field in the vehicle interior can be performed accurately including the head related transfer function.

According to the vehicle interior sound field automatic correction system (3) of the present invention, since the plurality of microphones are attached to the headrest of the seat in the vehicle interior, the microphones are attached to both ears of the listener. There is no need for it, and there is no need to let people hear the jarring test sound.

Further, according to the vehicle interior sound field automatic correction system (4) of the present invention, since the soundproofing material is attached to the hole side of the ears of the plurality of microphones, the microphones of the listener's ears are attached. Even if it is attached to, the noisy test signal generated at the time of sound field correction does not have to be heard by a person, and the test signal generated at the time of sound field correction can be received and fed back to both ears of the listener, Therefore, the sound field in the vehicle compartment can be automatically corrected with high accuracy including the head related transfer function.

Further, according to the vehicle interior sound field automatic correction system (5) of the present invention, since the headrest is provided with the microphone insertion portion into which the microphone can be inserted, the microphone is attached to the headrest microphone insertion portion at the time of sound field correction. You can easily attach it just by inserting it.

Further, according to the vehicle interior sound field automatic correction system (6) of the present invention, since the microphone is provided with the mounting means to the headrest, the microphone can be easily mounted to the headrest.

[Brief description of drawings]

FIG. 1 is a block diagram showing an automatic vehicle interior sound field correction system according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a hardware configuration of an audio system equipped with the vehicle interior sound field automatic correction system according to the first embodiment.

FIG. 3 is a plan sectional view showing a passenger car equipped with the audio system of the first embodiment.

FIG. 4 is a perspective view showing a configuration of a microphone according to a second embodiment of the present invention.

FIG. 5 is a perspective view showing a configuration of a microphone according to a third embodiment of the present invention.

FIG. 6 is a front view showing a state in which a microphone according to a fourth embodiment of the present invention is attached to a headrest of a seat.

FIG. 7 is a side view showing a state in which the headrest according to the fourth embodiment is viewed from the side.

FIG. 8 is a front view showing a state in which a microphone according to a fifth embodiment of the present invention is attached to a headrest of a seat.

FIG. 9 is a side view showing a state in which the headrest according to the fifth embodiment is viewed from the side.

FIG. 10 is a front view showing a state in which a microphone according to a sixth embodiment of the present invention is attached to a headrest of a seat.

FIG. 11 is a side view showing a state in which the headrest according to the sixth embodiment is viewed from the side.

FIG. 12 is a plan view showing an arrangement of a speaker and a microphone for explaining a problem of the conventional vehicle interior sound field automatic correction system.

[Explanation of symbols]

 1 Left Speaker 2 Right Speaker 3 Left Microphone 4 Right Microphone 5 M Sequence Signal Generating Means 6 Audio Capture Means 7 Impulse Response Signal Restoring Means 8 Frequency Characteristic Analyzing Means 9 Equalizer Coefficient Setting Means 10 Speaker Volume Level Setting Means 11 Speaker Delay Time Setting Means 17 Automobile 22,23 Headrest 25 Ear hole 26,27 Soundproof material 28 Microphone insertion part 29 Microphone hook 30 Rubber band 35 Vehicle compartment 41,42 Microphone

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H04R 5/02 F H04S 7/00 Z 8421-5H

Claims (6)

[Claims] 1. An automatic vehicle interior sound field correction system for automatically correcting a sound field formed by an audio system installed in a vehicle interior, wherein a plurality of said audio systems generate a test signal. Of the test signal generating means for converting the sound into a voice by the speaker, a voice capturing means for capturing as a voice signal the test response signal collected by the plurality of microphones placed at the listening position in the vehicle interior, and the voice capturing means of the voice capturing means. Speaker volume level setting means for setting the volume level of each speaker by an output signal, impulse response signal restoring means for restoring the test response signal captured by the voice capturing means as an impulse response signal, and the impulse response signal restoration Frequency response of the impulse response signal by fast Fourier transforming the impulse response signal restored by the means Frequency characteristic analysis means for analyzing
Equalizer coefficient setting means for setting an equalizer coefficient for correcting the frequency characteristic, and calculating the arrival time of the voice from each speaker to each microphone based on the impulse response signal output from the impulse response signal restoring means And a speaker delay time setting means for setting a delay time of a sound output from each of the speakers based on the arrival time. 2. The vehicle interior sound field automatic correction system according to claim 1, wherein the plurality of microphones are attached to both ears of a person sitting in a seat in the vehicle interior. 3. The vehicle interior sound field automatic correction system according to claim 1, wherein the plurality of microphones are attached to a headrest of a seat in the vehicle interior. 4. The vehicle interior sound field automatic correction system according to claim 2, wherein a soundproof material is attached to the ear holes of the plurality of microphones. 5. The vehicle interior sound field automatic correction system according to claim 3, wherein the headrest includes a microphone insertion portion into which the microphone can be inserted. 6. The vehicle interior sound field automatic correction system according to claim 3, wherein each of the microphones is provided with a mounting means to the headrest.