JPH0730994A - On-vehicle audio device - Google Patents

Abstract

PURPOSE:To facilitate the conversation in an automobile compartment. CONSTITUTION:A band limit is performed for the signal collected by a microphone 1 for front seat, and the signal is delayed by 21ms and 19ms for a front seat left side speaker 2a and a front seat right side speaker 2b, respectively, and the signal is outputted. Further, the signal is delayed by 31 ms and 29 ms for a back seat left side speaker 4a and a back seat right side speaker 4b, respectively, and the signal is outputted. The output level of the speaker for front seat is adjusted so as to be 0.7 times as much as the output level of the speaker for back seat. A band limit is performed for the signal collected by the microphone 3 for back seat, and the signal is delayed by 19ms and 21ms for the back seat left side speaker 4a and a back seat right side speaker 4b, respectively, and the signal is outputted. Further, the signal is delayed by 29ms and 31ms for the front seat left side speaker 2a and the front seat right speaker 2b, respectively, and the signal is outputted. The output level of the speaker for back seat is adjusted so as to be 0.7 times as much as the output level of the speaker for front seat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an audio device that expands the voice of a vehicle occupant, and more particularly to an audio device that controls the sound field in the passenger compartment to improve the interactivity.

[0002]

2. Description of the Related Art In the passenger compartment, front seats and rear seats do not face each other, and because of engine noise and noise from the outside while driving, there are people in the front seats and those in the rear seats. It is difficult to have a dialogue with. A device for facilitating conversation in a vehicle is disclosed in Japanese Patent Publication No. 35132/1993 and Japanese Patent Laid-Open No. 2-3123.
It is proposed in Japanese Patent Publication No. 49.

In these devices, a microphone arranged in the front of the vehicle compartment drives a speaker arranged in the rear of the vehicle compartment, and a microphone arranged in the rear of the vehicle compartment is arranged in the front of the vehicle compartment. Is configured to drive.

[0004]

Although the above-mentioned conventional device functions sufficiently as a means for simply speaking, it is insufficient in speaking while confirming the transmission of one's own voice. , It was not possible to make the space inside the car room have a natural sound that is easy to talk to.

Therefore, it is desired to improve the acoustic characteristics in the passenger compartment so that the voice transmission of one's own voice can be confirmed and an environment in which it is easier to talk is created. The present invention has been made in view of the above points, and an object of the present invention is to provide an in-vehicle acoustic device that satisfies such requirements.

[0006]

According to the on-vehicle audio system of the present invention, at least one microphone is arranged in the upper part of the front seat of the passenger compartment, and at least one microphone is arranged in the upper part of the rear seat. At least one loudspeaker is arranged in front of the backrest, at least one loudspeaker is arranged behind the backrest of the front seat, and the output signal of each microphone is processed to drive each speaker. In the audio device, each loudspeaker is configured to be driven by signals delayed by three or less different delay times.

In the on-vehicle audio system, the delay time is set to 18 ms to 42 ms while the signal from the microphone in the front seat is output to the loudspeaker in the front seat, and the signal from the microphone in the front seat is loud. 28ms between output to the container
To 52 ms, 18 ms to 42 ms while the signal from the rear seat microphone is output to the rear loudspeaker, and 2 while the signal from the rear seat microphone signal is output to the front loudspeaker.
It is set to 8 ms to 52 ms.

Further, in each of the vehicle-mounted acoustic devices,
Loudspeakers are placed on the left and right so that they are paired in front of and behind the back of the front seat.
The difference is about ms.

Further, in each of the on-vehicle acoustic devices,
The signal level of the signal from the microphone above the front seat that drives the loudspeaker arranged in front of the backrest of the front seat is set to 0 relative to the level of the signal that drives the loudspeaker located behind the backrest of the front seat. The ratio of 5 to 0.8 is set, and the level of the signal that drives the loudspeaker placed behind the back of the front seat is driven by the signal of the microphone above the back of the seat and drives the loudspeaker placed in front of the back of the front seat. 0.5 to 0.
The ratio is 8.

Further, in each of the vehicle-mounted acoustic devices,
The microphone signal is passed through a band-pass filter that passes a signal of 250 Hz to 2 KHz.

[0011]

According to the on-vehicle audio system of the invention, the voice signal collected by the microphone in the upper part of the front seat is inputted to the signal processing device and is band-limited by the band-pass filter of 250 Hz to 2 kHz, and then the loud sound for the front seat is produced. 18-42ms for loudspeakers, 28-52ms for rear loudspeakers
And the output level of the loudspeaker for the front seats is adjusted to be 0.5 to 0.8 with respect to the output level of the loudspeaker for the rear seats to drive each loudspeaker. To do.

In this way, the voice of the person who speaks in the front seat is heard as a direct sound from the speaker, and then the delayed voice is output first from the loudspeaker in the front seat and then from the loudspeaker from the rear seat. Since the position of the speaker is confirmed by the preceding effect of the sound because it is heard, a higher level of sound than the direct sound is reproduced from the loudspeaker for the rear seats, and the clarity of the conversation is also improved. You will be able to have a clear conversation even when the noise or surrounding noise is extremely high.

Further, the speaker himself also receives the delayed sound from the loudspeaker in the front seat and the sound from the rear seat that is further delayed,
You can hear your voice with a lingering voice, you can easily hear your own voice, you can check how your voice is transmitted, and you can talk easily without feeling the need to raise your voice.

On the other hand, similarly, in the rear seat, the voice signal collected by the microphone above the rear seat is input to the signal processing device, band-limited by the band-pass filter of 250 Hz to 2 kHz, and then the loudspeaker for the rear seat. To 1
8 to 42 ms, the front loudspeaker is delayed by 28 to 52 ms, and the output level of the rear loudspeaker is 0.5 to 0.8 with respect to the output level of the front loudspeaker. Each loudspeaker is adjusted so that it becomes the ratio of.

By doing so, the voice of the person who speaks in the rear seat is heard as a direct sound from the speaker, and then the delayed voice is output first from the rear loudspeaker and then from the front loudspeaker. Since it is heard, the positional relationship of the speaker is confirmed by the preceding effect of the sound, and at the same time, a sound with a higher level than the direct sound is reproduced from the loudspeaker for the front seat, which improves the clarity of the conversation, The same effect as when talking in the front seat is obtained.

Further, since the delay processing is applied not only to the voice coming directly from the speaker but also to the entire sound in the vehicle compartment, it is possible to obtain an effect as if the reverberation time in the vehicle compartment was lengthened. .

Furthermore, by changing the delay time on the left side and the right side of the loudspeakers for the front and rear seats by about 2 ms, it becomes possible to talk in a very natural sound.

By limiting the band in the range of 250 Hz to 2 kHz, noise unnecessary for conversation can be eliminated and the intelligibility can be improved. Then, howling can be reduced as much as possible in combination with suppressing the output level of the loudspeaker closer to the microphone to be a ratio of 0.5 to 0.8 with respect to the output level of the farther loudspeaker. it can.

The above effect can be obtained by driving each loudspeaker with a signal delayed by three or less different delay times, but if the loudspeaker is driven by a signal processed with more delay times than this. The clarity of the conversation is impaired.

As a result of various tests, it was found that the above-mentioned output level setting and delay time setting provided the described effect without impairing the intelligibility of conversation.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An on-vehicle audio system according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the arrangement of microphones and loudspeakers when the vehicle-mounted audio system according to the embodiment of the invention is applied to a sedan type vehicle.

As shown in the figure, the front seat microphone 1 is arranged in the center of the upper front seat, and the rear seat microphone 3 is arranged in the center of the upper rear seat. In addition, the front left loudspeaker 2a
Is attached to the left front door, and the front seat right loudspeaker 2b is attached to the right front door. The rear seat left loudspeaker 4a and the rear seat right loudspeaker 4b are attached to the left and right of the rear tray, respectively.

As shown in FIG. 2, the front seat microphone 1 is provided.
The audio signal collected in (1) is amplified by the microphone amplifier 5 and then input to the signal processing device 9. Further, the audio signal collected by the rear seat microphone 3 is amplified by the microphone amplifier 6 and then input to the signal processing device 9.

The signal processing device 9 outputs a signal obtained by processing the input signal to the front-speaker loudspeaker power amplifiers 7a and 7b and the rear-speaker loudspeaker power amplifiers 8a and 8b. The front-speaker loudspeaker power amplifiers 7a and 7b amplify the input signals to drive the front-seat left loudspeaker 2a and the front-seat right loudspeaker 2b, respectively.
Similarly, the rear-speaker loudspeaker power amplifiers 8a and 8b amplify the input signals to drive the rear-seat left-side loudspeaker 4a and the rear-seat right-side loudspeaker 4b, respectively.

FIG. 3 shows a signal flow when the signal processing device 9 is configured by a DSP (digital signal processor). The signal from the microphone amplifier 5 is a high-pass filter (cutoff frequency 250 Hz) composed of a multiplier 10, a delay circuit 11, a multiplier 12, an adder 13 and a subtractor 14, and a multiplier 15, an adder 16 and a delay circuit 1.
After passing through a low-pass filter (cutoff frequency 2 kHz) composed of 7 and a multiplier 18, the signal is input to the delay circuit with multi-tap 19a.

The multi-tap delay circuit 19a delays the input signal by 31 ms, 29 ms, 21 ms and 19 ms and outputs the delayed signals to the multipliers 20a, 21a, 22a and 23a, respectively.

As with the microphone amplifier 5, the signal from the microphone amplifier 6 passes through the high-pass filter and the low-pass filter, and then the delay circuit 19 with multi-tap.
Input to b. The multi-tap delay circuit 19b receives the input signals of 31 ms, 29 ms, 21 ms and 19 m, respectively.
delay by s and multiply by multipliers 20b, 21b, 22b and 23, respectively.
output to b.

The outputs of the multipliers 22a and 21b are the adder 24.
It is added at a and output to the front-speaker loudspeaker power amplifier 7a. The front-speaker loudspeaker power amplifier 7a power-amplifies the input signal to drive the front-seat left loudspeaker 2a.

The outputs of the multipliers 23a and 20b are the adder 25.
It is added at a and output to the front-speaker loudspeaker power amplifier 7b. The front-speaker loudspeaker power amplifier 7b power-amplifies the input signal to drive the front-seat right loudspeaker 2b.

The outputs of the multipliers 20a and 23b are the adder 24.
It is added at b and output to the power amplifier 8a for the rear loudspeaker. The rear-speaker loudspeaker power amplifier 8a power-amplifies the input signal and drives the rear-seat left loudspeaker 4a.

The outputs of the multipliers 21a and 22b are the adder 25.
It is added at b and output to the power amplifier 8b for the rear loudspeaker. The rear-speaker loudspeaker power amplifier 8b power-amplifies the input signal to drive the rear-seat right-side loudspeaker 4b.

Incidentally, the multipliers 20a, 21a, 20b, 2
The gain ratio of 1b and the multipliers 22a, 23a, 22b, and 23b is 1: 0.7. In the figure, the part enclosed by the dotted line is digitally processing the signal, and
There are a D converter and a DA converter, but they are not shown.

By using such a signal processing device, the signal collected by the front seat microphone 1 is 250H.
The band is limited to z to 2 kHz, delayed by 21 ms for the front left loudspeaker 2a and delayed by 19 ms for the front right loudspeaker 2b. 31ms for the rear left loudspeaker 4a and 29ms for the rear right loudspeaker 4b
Each is delayed and output. The output level of the front loudspeaker is adjusted to be 0.7 times the output level of the rear loudspeaker.

On the other hand, the signal collected by the rear microphone 3 is band-limited to 250 Hz to 2 kHz, delayed by 19 ms for the rear left loudspeaker 4a, and delayed for 21 ms for the rear right loudspeaker 4b and output. To be done. Further, the output is delayed by 29 ms for the front left loudspeaker 2a and 31 ms for the front right loudspeaker 2b. The output level of the rear loudspeaker is adjusted to be 0.7 times the output level of the front loudspeaker.

The output pattern of each loudspeaker is shown in FIG. As shown in the figure, the output wave consists of A wave and B wave, of which A wave comes from the microphone near the loudspeaker (for example, if the loudspeaker is attached to the front door, it is attached to the upper front seat). Signal, and the direct wave is delayed by about 20 ms.

Further, the B wave is due to a signal from a microphone far from the loudspeaker (for example, a microphone attached to the upper portion of the rear seat in the case of a loudspeaker attached to the front door), and 30 ms with respect to the direct wave. There is some delay.

By setting the delay time of each loudspeaker as described above, the A wave and the B wave on the left and right sides of both the front and rear seats are set.
The distance from the waves is adjusted to be different, which prevents the reverberation from becoming unnatural. The level of the A wave is 0.7 times that of the B wave.

Although the embodiment is configured as described above, the invention is not limited to this. For example, since the vehicle compartment space is narrow, instead of transmitting the signal from the microphone through the wiring material, a weak radio wave, It may be transmitted by ultrasonic waves or infrared rays. With such a structure, the trouble of wiring can be eliminated.

[0039]

According to the on-vehicle audio system of the present invention, the microphones are attached to the upper front seat and the upper rear seat, and the front loudspeaker and the rear loudspeaker are provided in front of and behind the front seat back, respectively. Since the signal processing device mounts and processes the signals collected by the microphone as described above and outputs the signals from the front and rear loudspeakers, it is possible to reduce running noise and ambient noise. Conversations can be made smoothly between the front and rear seats even when it is expensive.

Also, since the speaker himself can easily hear his / her own voice, it is not necessary to raise the voice when speaking, and it is effective in suppressing fatigue caused by speaking. In addition, it has the effect of suppressing howling as much as possible, making it easier to talk in a natural sound.

Further, if the signal processing device is constructed by a DSP as shown in the embodiment, the construction of the device becomes simple and it can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 (a) is a plan view showing the arrangement of microphones and loudspeakers when the on-vehicle audio system according to an embodiment of the present invention is applied to a sedan type vehicle, and FIG. 1 (b) is the same side view. It is a figure.

FIG. 2 is a block diagram showing a configuration of the vehicle-mounted acoustic device.

FIG. 3 is a diagram showing a signal flow when the signal processing device of the vehicle-mounted audio device is configured by a DSP.

FIG. 4 is a pattern diagram showing a loudspeaker output level of the vehicle-mounted audio device and its timing.

[Explanation of symbols]

 1 front microphone 2a front left speaker, 2b front right speaker 3 rear microphone 4a rear left speaker 4b rear right speaker 5 microphone amplifier 6 microphone amplifier 7a, 7b power for front speaker Amplifier 8a, 8b Power amplifier for rear loudspeaker 9 Signal processing device 10 Multiplier 11 Delay circuit 12 Multiplier 13 Adder 14 Subtractor 15 Multiplier 16 Adder 17 Delay circuit 18 Multiplier 19a, 19b Multi-tap delay circuit 20a Multiplier 24a, 24b Adder 25a, 25b Adder

Claims (5)

[Claims] 1. At least one microphone is arranged in the upper part of the front seat of the passenger compartment, at least one microphone is arranged in the upper part of the rear seat, and at least one loudspeaker is arranged in front of the backrest of the front seat. In a vehicle-mounted audio device in which at least one loudspeaker is disposed behind the backrest of the front seat, and the output signal of each microphone is signal-processed to drive each speaker, each loudspeaker is different in three types or less. An on-vehicle acoustic device configured to be driven by a signal delayed by a delay time. 2. The delay time is 18 ms to 42 ms while the signal from the microphone in the front seat is output to the loudspeaker in the front seat.
And 28 ms to 52 ms while the signal from the front microphone is output to the rear loudspeaker, and 18 ms while the signal from the rear microphone is output to the rear loudspeaker.
The in-vehicle audio device according to claim 1, wherein the microphone signal in the rear seat is 28 ms to 52 ms while the signal from the microphone in the rear seat is output to the loudspeaker in the front seat. 3. The vehicle-mounted system according to claim 1 or 2, wherein loudspeakers are arranged on the left and right so as to form a pair in front of and behind the back of the front seat, and the delay time is different by about 2 ms between the right and left loudspeakers. Audio equipment. 4. The level of a signal for driving a loudspeaker arranged in front of a backrest of a front seat by a signal of a microphone above the front seat is a level of a signal for driving a loudspeaker arranged behind a backrest of the front seat. Is 0.5 to 0.8, and the level of the signal that drives the loudspeaker located behind the front seat backrest by the signal from the microphone above the rear seats is located forward of the front seatback rest. 4. The vehicle-mounted acoustic device according to claim 1, wherein the ratio is 0.5 to 0.8 with respect to the level of the signal for driving the loud speaker. 5. The signal of the microphone is from 250 Hz to
5. The vehicle-mounted acoustic device according to claim 1, wherein a band-pass filter that allows a signal of 2 KHz to pass therethrough is passed through.