JPH06113400A - On-vehicle acoustic reproduction system - Google Patents

Abstract

PURPOSE:To provide the on-vehicle acoustic reproduction system in which generation of howling is prevented when an optional sound field is created by adding a reverberation sound or the like to a music signal from a speaker collected by a microphone in a vehicle cabin. CONSTITUTION:Speakers 2a,2b and rear speakers 3a,3b are installed to left/right front doors and on the rear side of a rear seat and microphones 4a,4b are installed on a ceiling 14 of a driver's seat and an assistant's seat. A sound from each speaker collected by the microphones 4a,4b is inputted to a DSP through a microphone amplifier, a low frequency cut-off use high pass filter and a notch filter for cutting off medium and high howling frequencies and an output signal adjusted and processed in the DSP is given to each power amplifier, and an output signal of the microphone 4a is outputted to the speaker 2b and the rear speaker 3a and an output signal of the microphone 4b is outputted to the speaker 2a and the rear speaker 3b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to vehicle-mounted sound reproduction suitable for suppressing howling and creating a natural sound field by filtering an output signal of a microphone in a vehicle compartment and processing it by a signal processing means. Regarding the system.

[0002]

2. Description of the Related Art Conventionally, in order to realize an arbitrary sound field feeling for indoor use, as shown in FIG. 6, a microphone 21 for collecting indoor sound is provided at a predetermined position.
1 collects the room sound, and the sound signal amplified by the microphone amplifier 25 is converted into a digital signal processor (hereinafter referred to as DSP).
That is, there is provided a sound reproducing device that processes and delays by 24, adjusts reflected sound and reverberant sound, and outputs the sound from a plurality of speakers 22 installed in a predetermined place in the room.

However, there is no on-vehicle sound reproducing device configured to collect the sound in the vehicle compartment using the microphone as described above, process the output signal with the DSP, and output the processed signal from the speaker. It was

[0004]

If the above-mentioned conventional sound reproducing apparatus for a general room is directly applied to the vehicle interior, the vehicle interior is so small that the distance between the speaker and the microphone cannot be secured so much that the sound from the speaker is produced. Howling was likely to occur because the output signal was collected directly by the microphone, amplified, and output from the speaker.

The present invention has been made in view of the above points, and an object of the present invention is to solve the drawbacks of the conventional example, and to add reverberation to a tone signal from a speaker collected by a microphone in a vehicle compartment. It is an object to provide an in-vehicle sound reproduction system capable of preventing howling from occurring when an arbitrary sound field is created by adding the sound field.

[0006]

The on-vehicle sound reproduction system of the present invention comprises a speaker, a microphone for collecting musical sounds radiated from the speaker, and a signal processing means in the vehicle compartment. In the in-vehicle sound reproduction system configured to process the sound signal processed by the signal processing means and output it from the speaker, the sound signal collected by the microphone installed in the front left side of the vehicle compartment is installed in the front right side. The sound signal output from the speaker and the speaker installed on the left rear side, and collected by the microphone installed on the right front side is output from the speaker installed on the left front side and the speaker installed on the right rear side. In addition, the sound signal collected by the microphone installed on the left rear of the vehicle The sound signals output from the installed speaker and the speaker installed on the right rear side, and the sound signals collected by the microphone installed on the right rear side are output from the speaker installed on the right front side and the speaker installed on the left rear side. It is configured as follows.

Further, the removing circuit for removing the howling frequency is provided in the connection circuit of the microphone.

Further, the connection circuit of the microphone is provided with a high-pass filter having a predetermined cutoff frequency.

Further, a cushioning member is arranged around the microphone to control the vibration of the peripheral members.

[0010]

According to the present invention, the sound collected by the microphone installed on the left rear of the vehicle compartment is output from the speaker installed on the left front and the speaker installed on the right rear, and installed on the right rear. Since the sound collected by the microphone is output from the speaker installed on the right front side and the speaker installed on the left rear side, it is possible to maximize the distance between the microphone and the speaker as in the above. A large margin can be secured, and the input signals of the front speaker and the rear speaker cross-connected to the microphone are crossed left and right, so that the reverberations collected from the microphone on one side can be heard from the other side. It is possible to eliminate the unnaturalness that occurs.

Further, a notch filter centering on the howling frequency is provided in the connection circuit of the microphone as a removing means for removing the frequency causing the howling in the middle and high frequencies to suppress the howling occurrence.

Further, a high-pass filter having a cut-off frequency of about 300 Hz is provided in the connection circuit of the microphone to cut low-frequency sounds and prevent howling in the low-frequency range.

Further, a cushioning member is arranged around the microphone to cut off vibration of a member to which the microphone is attached and peripheral members, thereby eliminating generation of abnormal noise of the microphone due to vibration of these members.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vehicle-mounted sound reproduction system according to the present invention will be described with reference to FIGS. FIG. 1 (A) is a plan sectional view of a first embodiment implemented on a sedan type automobile, FIG. 1 (B) is a side sectional view of the same, and FIG. 2 shows a microphone mounted on a ceiling in the first embodiment. FIG. 3 is an enlarged side sectional view showing the same, and FIG. 3 is a block diagram showing the connection between the microphone and the speaker used in the first embodiment. FIG. 4 is a plan sectional view of the second embodiment, and FIG. 5 is a block diagram showing a connection between a microphone and a speaker used in the second embodiment.

In the figure, 1 is a sedan type automobile,
1a is a passenger compartment. Reference numerals 2a and 2b denote right and left speakers installed in the front of the vehicle compartment, which are installed in the front door. Reference numerals 3a and 3b denote right and left rear speakers installed in the rear of the passenger compartment, and are installed upward on the parcel tray behind the rear seats. Microphones 4a and 4b are installed on the ceilings of the front center of the right driver's seat and the left passenger's seat in front of the passenger compartment 1a, and collect ambient sounds.

Reference numeral 5 denotes a head unit which serves as a signal source,
It is composed of a tuner, a CD player, a cassette deck, and the like. 6a and 6b are power amplifiers for driving the speakers 2a and 2b, respectively, and 6c and 6d are rear speakers 3a and
3b is a power amplifier for driving each. Reference numeral 7 is a signal processing means DSP (digital signal processor)
And processes the signals from the two microphones 4a and 4b to produce the speakers 2a and 2b and the rear speakers 3a and 3b.
It has respective terminals for outputting to. Microphone amplifiers 8a and 8b amplify the output signals of the microphones 4a and 4b. 9 is a high-pass filter, and the predetermined cutoff frequency is about 300 Hz. Reference numeral 10 is a notch filter which is a removing means, and cuts centering on frequencies in the middle and high frequencies where howling is generated.

Reference numeral 11 denotes a cushioning member, which is mounted so as to cover the microphones 4a and 4b mounted in the ceiling,
The microphones 4a and 4b are the roof 12 and the front window 1.
3. The vibration of the interior of the ceiling 14 is not picked up, and the generation of abnormal noise is prevented.

As shown in FIGS. 1 and 3, when the microphones 4a, 4b are installed on the ceiling 14 of the driver's seat and the passenger's seat, after being amplified by the microphone amplifiers 8a, 8b, the high-pass filter 9, D through the notch filter 10
The delay signal, the reflected sound, and the reverberation sound are added to the DSP 7 so that the DSP 7 produces a predetermined signal, and the frequency characteristic and the phase are adjusted so that the output signal is output from each power amplifier 6
a, 6b, 6c, 6d.

At this time, the signal from the microphone 4a on the driver's side enters the power amplifiers 6b and 6c, is mixed with the signal from the head unit 5 and is output, and the left speaker 2b far from the microphone 4a is sufficiently supplied. It is supplied and output to the right rear speaker 3a at a long distance.

Similarly, the signal from the microphone 4b on the passenger side enters the power amplifiers 6a and 6d, and is transmitted to the right speaker 2a farther from the microphone 4b and the left rear speaker 3b which is sufficiently far away. Supplied and output.

When the microphones 4a and 4b are installed on the right side and the left side of the ceiling 14 of the rear seat, as shown in FIG. 5, the connection between the microphones 4a and 4b and the DSP 7 is made the same as in FIG. The output of the DSP 7 is passed through the power amplifiers 6a, 6b, 6c and 6d, and the signal from the right microphone 4a is output from the front speaker 2a and the two rear speakers 3a and 3b which are sufficiently far from the microphone 4a. Similarly to the above, the signal from the left microphone 4b is supplied to and output from the far left rear speaker 3b, and the front speaker 2b and the two rear speakers 3a, which are sufficiently distant from the microphone 4b. The far right rear speaker 3a of 3b
Is supplied to and output.

The operation of the present invention configured as above will be described. In the first embodiment in which the microphones 4a and 4b are installed on the ceiling 14 of the driver's seat and the passenger's seat, as shown in FIGS. 1 to 3, the heads emitted from the speakers 2a, 2b and the rear speakers 3a, 3b are used. Unit 5 and DSP
The musical tones 7 are collected by the microphones 4a and 4b as sounds around each seat, and the sound signals are input to the high-pass filter 9 via the microphone amplifiers 8a and 8b. In this high-pass filter 9, the low frequency range of about 300 Hz or less is cut off because the reverberation time is long and it is not necessary to intentionally add reverberation by the DSP 7, and howling is likely to occur.

Then, in the notch filter 10 in the next stage,
The shape and interior condition of the vehicle interior 1a and the microphone 4a,
The centering is on the mid-high range howling frequency, which is almost determined by the position of 4b.

Notch filter 10 input to DSP 7
Output signal is processed such that the sound field around the microphones 4a, 4b becomes a predetermined sound field, that is, delayed, reflected sound or reverberant sound is added, frequency characteristics and phase are adjusted. A desired sound field is created in the vehicle interior 1a.

The sound signal collected by the microphone 4a is mixed with the signal of the head unit 5 by the power amplifier 6b, and the left speaker 2b cross-connected to secure the distance to the microphone 4a, and the distance is sufficiently secured. The sound is radiated as a sound from the rear speaker 3a on the right side, and the howling margin is maximized, and the reverberation of the sound on the right side is eliminated from the speaker 2b on the left side.

The sound signal collected by the microphone 4b is also
Similarly to the above, the right speaker 2a and the left rear speaker 3b are radiated as sound to maximize the howling margin, and eliminate the unnaturalness that the reverberation of the left sound is heard from the right speaker 2a. ing.

As a result, howling in the low range and the mid-high range is suppressed, and a natural sound field is created in the vehicle interior 1a.

In the second embodiment in which the microphones 4a and 4b are installed on the left and right sides of the ceiling 14 of the rear seat, as shown in FIGS.
The sound signals collected by 4b are radiated as sounds from the speakers 2a, 2b on the same side to the speakers 2a, 2b on the front side where the distance is sufficiently secured, and to the speakers 3a, 3b on the rear side. , Cross connection is made to secure a distance, and the sound is emitted from the left rear speaker 3b and the right rear speaker 3a, respectively.

As a result, similarly to the above, howling in the low range and the mid-high range is also suppressed, and a natural sound field is created in the vehicle interior 1a.

The reverberation sound and the like added by the DSP may be applied to the signal from the head unit 5.

[0031]

According to the on-vehicle sound reproducing system of the present invention, the following effects can be obtained. (1) The microphones 4a and 4b are installed in the vehicle compartment, the sounds output by the speakers 2a and 2b and the rear speakers 3a and 3b are collected, and the howling frequencies in both the middle and high frequencies and the low frequencies included in this output signal are collected. , Notch filter 10
Since it is removed by the high-pass filter 9, howling can be sufficiently suppressed. (2) Microphones 4a and 4b are on the ceiling 1 of the driver's seat and passenger's seat
4 installed in front door speaker 2
Cross connection is made with a and 2b to secure a distance, and the rear speakers 3a and 3b are connected to the same side as the microphones 4a and 4b. Further, when the microphones 4a and 4b are installed on the left and right sides of the ceiling 14 of the rear seat, those on the same side as the speakers 2a and 2b are connected, and the rear speaker 3
A distance is secured by cross-connecting with a and 3b. In this way, by separating the microphones 4a, 4b from the speakers 2a, 2b and the rear speakers 3a, 3b as much as possible,
Howling can be greatly suppressed. (3) Since the cushioning member 11 is arranged around the microphones 4a and 4b, vibration of the roof 12, the front window 13, the interior of the ceiling 14 and the like is not picked up, and the generation of abnormal noise can be prevented. (4) With the above items (1) to (3), a very natural sound field can be created in the vehicle interior.

[Brief description of drawings]

FIG. 1A is a plan sectional view showing a first embodiment of the present invention,
(B) It is a side sectional view showing the first embodiment.

FIG. 2 is an enlarged side cross-sectional view showing an installed state of the microphone of the first embodiment.

FIG. 3 is a block diagram showing a connection between a microphone and a speaker according to the first embodiment.

FIG. 4 is a plan sectional view showing the second embodiment.

FIG. 5 is a block diagram showing a connection between a microphone and a speaker according to the second embodiment.

FIG. 6 is a block diagram showing an example of connection between a microphone and a speaker of a conventional example.

[Explanation of symbols]

 1 Car 1a Cab 2a, 2b Speaker 3a, 3b Rear speaker 4a, 4b Microphone 5 Head unit 6a, 6b, 6c, 6d Power amplifier 7 DSP 8a, 8b Microphone amplifier 9 High-pass filter 10 Notch filter 11 Buffer member 12 Roof 13 Front Window 14 ceiling

Claims (5)

[Claims] 1. A vehicle interior is provided with a speaker, a microphone for collecting musical sounds radiated from the speaker, and a signal processing means, wherein the sound signal collected by the microphone is processed by the signal processing means, and the In an in-vehicle sound reproduction system configured to output, a sound signal collected by a microphone installed on the left front side in the vehicle compartment is output from a speaker installed on the right front side and a speaker installed on the left rear side, and the right side An in-vehicle sound reproduction system characterized in that a sound signal collected by a microphone installed in front is output from a speaker installed in front of the left side and a speaker installed in rear of the right side. 2. A vehicle interior is provided with a speaker, a microphone for collecting musical sound radiated from the speaker, and a signal processing means. The sound signal collected by the microphone is processed by the signal processing means and output from the speaker. In the vehicle-mounted sound reproduction system configured as described above, the sound signal collected by the microphone installed on the left rear side in the vehicle interior is output from the speaker installed on the left front side and the speaker installed on the right rear side, and An in-vehicle sound reproduction system characterized in that a sound signal collected by a microphone installed in the rear is output from a speaker installed on the right front side and a speaker installed on the left rear side. 3. The on-vehicle sound reproduction system according to claim 1, wherein the microphone connection circuit is provided with a removing means for removing a howling frequency. 4. The on-vehicle sound reproduction system according to claim 1, wherein a high-pass filter having a predetermined cutoff frequency is provided in the connection circuit of the microphone. 5. The in-vehicle sound reproduction system according to claim 1, wherein a cushioning member is arranged around the microphone.