JPH04137897A - On-vehicle acoustic equipment - Google Patents

Abstract

PURPOSE:To eliminate distortion in the frequency characteristic due to a reflected sound and a bypassed sound completely by providing a correction signal generating means and a sub speaker placed in the vicinity of an ear of a listener to the equipment. CONSTITUTION:An amplifier 5 consists of a left channel amplifier circuit 11, a right channel amplifier circuit 11R and a sound field correction control circuit alphaand sub speakers 9L, 9R are arranged respectively in the vicinity of both ears such as to the left and right of a head rest in addition to main speakers 7L, 7R reproducing an original signal fed from the amplifier circuits 11L, 11R. Then a correction signal generated from the sound field correction control circuit alpha is fed to the sub speakers to output a corrected sound thereby cancelling a harmful noise outputted from the main speakers and giving effect on the sound reaching the ears of the listener directly. Thus, distortion in the frequency characteristic due to a reflected sound with a short delay time and a bypass sound is completely eliminated, the separation characteristic is considerably improved and the sound image localization is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an in-vehicle audio device that performs sound field correction for audio in a vehicle.

(Prior Art) Conventionally, as an in-vehicle audio device mounted on a vehicle such as an automobile, there is one as shown in FIG. 4, for example.

The in-vehicle audio device 103 shown in FIG.
It consists of a sound source device 105 including an amplification device installed in the center of the instrument, a right speaker 37R1 and a left speaker 37L installed on both the left and right sides of the instrument or inside the door (for example,
(issued by Nissan Motor Co., Ltd., Service Bulletin No. 578)
.

In this in-vehicle audio device 103, the left speaker 10
A part of the sound reproduced from the left speaker 107L directly reaches the listener's right ear via path C, and a part of the sound reproduced from the left speaker 107L reaches the listener via a path that is reflected by the right side glass 111R. When the sound reaches the right ear, a sound pressure characteristic as shown in FIG. 5(a) is obtained.

Note that the sound pressure characteristics along route C and the sound pressure characteristics along route C1 are indicated by D (the same applies hereinafter).

Also, a part of the sound played from the left speaker 107L directly reaches the listener's left ear via the path, and -m of the sound played from the left speaker 107L reaches the right side glass 11.
1R and reaches the listener's left ear on the path B reflected by the viscosity.
Sound pressure characteristics as shown in FIG. 5(b) are obtained.

Similarly, a portion of the sound played from the right speaker 107R directly reaches the listener's right ear via path E, and a portion of the sound played from the right speaker 107R reaches the left side glass 11.
1 and reaches the listener's right ear on the reflected path F,
A sound pressure characteristic as shown in FIG. 5(c) is obtained.

Also, a part of the sound played from the right speaker 107R directly reaches the listener's left ear via the path H, and a part of the sound played from the right speaker 107R reaches the left side glass 11.
It reaches the listener's left ear via path G reflected by 1L,
A sound pressure characteristic as shown in FIG. 5(d) is obtained.

In other words, in a car-mounted audio system, the sound that reaches the listener through reflection or detouring is slightly delayed from the sound AX that reaches the ear directly from the speaker (hereinafter referred to as the original sound). As shown by X in (e), the sound quality deteriorates due to the aforementioned reflected sound. Therefore, in the conventional vehicle-mounted audio device, the deterioration in sound quality due to the reflected sound described above is corrected using the frequency-sound pressure characteristic so as to have the characteristic Y shown in FIG. 5(e).

(Problems to be Solved by the Invention) However, in the above-mentioned conventional in-vehicle audio device,
As mentioned above, sound quality has been improved using frequency-sound pressure characteristics, but this does not fundamentally improve sound quality, and the problem remains that so-called frequency irregularities remain, such as sounds of specific frequencies being too loud. was there. This "frequency frenzy" occurs because the reflected sound reaches the ear in a very short time (2 to 5 rrzec) compared to the original sound, as shown in area 2 in Figure 5(e). This occurs because the sound cannot be distinguished from reflected sound and is perceived as peaks and dips of a specific frequency.

The present invention has been made with attention to such conventional problems, and an object of the present invention is to provide an in-vehicle audio device that cancels harmful reflected sounds and the like.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides an in-vehicle audio device that outputs an original signal supplied from a sound source device as audio from a main speaker. a correction signal generating means for generating a correction signal for canceling harmful sounds that are output from the listener and directly reach the listener's ears; and a correction signal generating means provided near the listener's ears. The gist of the present invention is to include a sub-speaker that outputs corrected audio from the corrected signal generated by the sub-speaker.

(Function) In the in-vehicle audio device according to the present invention, in addition to the main speaker that reproduces the original signal supplied from the sound source device, sub-speakers are disposed near both ears, for example, on the left and right sides of the headrest.

Then, a correction signal generated by the correction signal generation means is supplied to the sub-speaker, and a corrected sound is output from the sub-speaker, thereby affecting the sound that is output from the main speaker and directly reaches the ears of the listener. It is designed to cancel out the harmful noise that is caused by the noise.

(Example) The present invention will be explained below based on the drawings.

FIG. 1 is a configuration diagram showing an embodiment of the audio device of the present invention.

In FIG. 1, a vehicle 1 such as an automobile is equipped with an in-vehicle audio device 3. As shown in FIG.

This in-vehicle audio device 3 includes an amplifier device 5, left and right speakers 7R, 7L, and left and right sub-speakers 9R19L.

Specifically, the amplifier device 5 is provided at the front of the vehicle 1. The amplifying device 5 includes a sound field correction control circuit α, which is a correction signal generating means that amplifies the original signal from the sound source device and forms a correction signal capable of canceling unnecessary indirect sounds.

The left and right speakers 7R, 7L are installed on both front sides of the vehicle 1, and convert the signal from the amplifier 5 into sound.

The left and right sub-speakers 9R, 9L are arranged on both sides of the headrest 8 (near the ears of the listener), and convert the correction signal from the sound field correction control circuit α of the amplifier 5 into sound.

FIG. 2 is a block diagram showing the configuration of the amplifying device 5. As shown in FIG.

The amplifier device 5 shown in FIG. 2 includes a sound field correction control circuit α and is configured as follows.

That is, the amplifier device 5 has a left channel amplifier circuit 11.
L, a right channel amplifier circuit 11R, and a sound field correction control circuit α. Here, the left channel amplifier circuit 11L amplifies the original signal of the left channel (L Ch) from a sound source device (not shown) and outputs it to the left main speaker 7L.
supply to. In addition, the right channel amplifier circuit 11R is
The original signal of the right channel (RCh) from a sound source device (not shown) is amplified and supplied to the left main speaker 7R.

The sound field correction control circuit α is configured as follows.

That is, the phase shift circuit 13L can change the phase of the left channel original signal by 180 degrees. Phase shift circuit 13
The signal from L has a delay time DT.

delay circuit 15L1 delay circuit 17L with delay time DT2,
Each of the signals is supplied to the delay circuit 19L with a delay time DT3.

The phase shift circuit 13R shifts the original signal of the right channel to 18
You can change the 0 degree phase. The signal from the phase shift circuit 13R is transmitted to the delay circuit 19R1 with a delay time DT4.
5 delay circuit 15R1 delay circuit 17H with delay time DT5
are supplied respectively.

The delay circuit 15L delays the signal from the phase shift circuit 13L by a delay time (DT+) in order to eliminate the harmful sound that reaches the right ear from the left main speaker 7L via the path C.

The delay circuit 17L delays the signal from the phase shift circuit 13L by a delay time (DT2) in order to eliminate harmful sound that reaches the right ear via a route from the left main speaker 7L.

Further, the delay circuit 19R is routed from the right main speaker 7R to the path F.
In order to eliminate the harmful sound that reaches the right ear via the phase shift circuit 13R, the signal from the phase shift circuit 13R is delayed by the delay time (DT4).

On the other hand, the delay circuit 15R connects the right main speaker 7R to the path H.
In order to eliminate the harmful sound that reaches the left ear via the phase shift circuit 13R, the signal from the phase shift circuit 13R is delayed by a delay time (DT5).

The delay circuit 17R delays the signal from the phase shift circuit 13R by a delay time (DTe) in order to eliminate harmful sound that reaches the left ear from the right main speaker 7R via the path G. In addition, the delay circuit 19L transmits the signal from the phase shift circuit 13L for a delay time (DT3
) minutes.

The outputs of the delay circuits 15L, 17L, and 19R are added by an adder 27L via level adjusters 21L, 23L, and 25R, and amplified by an amplifier circuit 29L, and then supplied to the right sub-speaker 9R. Delay circuit 15R17
The output of R, 19L is sent to a level adjuster 2 that adjusts the level.
The signals are added by an adder 27R via 1R, 23R, and 25L, amplified by an amplifier circuit 29R, and then supplied to the left sub-speaker 9L.

Next, the operation of the above-described embodiment will be explained with reference to FIG.

Originally, only the sound E as shown in FIG. 3(b)(R), which exits from the right main speaker 7R and passes through the path E, needs to reach the listener's right ear.

However, in reality, the right ear of the listener is
a) As shown in (R), the sound that comes out of the left main speaker 7L as a harmful indirect sound and passes through the route C, and the sound that comes out of the left main speaker 7L and is reflected on the right side glass etc. As shown in FIG. 3(b)(R), the right main speaker 7
The sound coming out from R, reflecting off the left side glass, etc., and passing through path F will reach the sound.

Similarly, the listener's left ear would normally hear the sound A as shown in FIG.
only need to be reached directly.

However, in the listener's left ear,
As shown in , the harmful indirect sound comes from the right main speaker 7R and passes through the path H, the sound comes out from the right main speaker 7R and is reflected by the left side glass, etc., and the sound comes from the third path.
As shown in FIGS. (c) and (L), the sound that comes out from the left main speaker 7L, is reflected by the right side glass, etc., and then reaches the sound that has passed through path B.

First, the correction operation for the right ear will be explained.

The original signal of the left channel is passed through the phase shift circuit 13 and 18.
0 degree phase is inverted. The output signal of this phase shift circuit 13L is supplied to a delay circuit 15L, a delay circuit 17L, and a delay circuit 19L. Similarly, the phase of the right channel original signal is inverted by 180 degrees by the phase shift circuit 13R.

The output signal of this phase shift circuit 13R is transmitted to the delay circuit 19
Supplied to R.

As shown in FIG. 3(a) (RH), the delay circuit 15L outputs a signal that has adjusted the delay time (DTl) of the harmful sound on the path C from the left main speaker 7L that reaches the right ear to the level adjuster 21L. supply to.

As shown in Figure 3 (a) (RH), the delay circuit 17L outputs a signal with adjusted delay time (DT2) of the harmful sound on the path from the left main speaker 7L reaching the right ear to the level adjuster 23L. supply to.

As shown in FIG. 3(b) (RH), the delay circuit 19R sends a signal that has adjusted the delay time (DT4) of the harmful sound on the path F from the right main speaker 7R that reaches the right ear to the level adjuster 25R. supply to.

Each level adjuster 21L, 23L, 25R adjusts the level of each output signal to a level that can cancel each harmful sound. The signal thus adjusted is sent to the adder 2
7L, amplified by the amplifier circuit 29L, and outputted as sound from the right sub-speaker 9R.

As a result, the sound from the right sub-speaker 9R has the opposite phase with respect to each harmful sound and is at the same level.
Each harmful sound in the listener's right ear will be canceled.

Next, the correction operation for the left ear will be explained.

The output signal whose phase has been inverted by 180 degrees by the phase shift circuit 13R is supplied to the delay circuit 15R1 and the delay circuit 17R. Similarly, the output signal of the phase shift circuit 13L is supplied to the delay circuit 19L.

As shown in FIG. 3(d) (LH), the delay circuit 15R sends a signal with adjusted delay time (DT5) of the harmful sound on the path H from the right main speaker 7R reaching the left ear to the level adjuster 21H. supply to.

As shown in FIG. 3(d) (LH), the delay circuit 17R sends a signal with adjusted delay time (DTs) of the harmful sound on the path G from the right main speaker 7R reaching the left ear to the level adjuster 23H. supply to.

As shown in FIG. 3(c) (LH), the delay circuit 19L sends a signal with adjusted delay time (DTs) of the harmful sound on the path B from the left main speaker 7L that reaches the left ear to the level adjuster 25H. supply to.

Each level adjuster 21R, 23R, 25L adjusts the level of each output signal to a level that can cancel each harmful sound.

The thus adjusted signals are added by an adder 27R, amplified by an amplifier circuit 29R, and output as sound from the left sub-speaker 9L. As a result, the sound from the left sub-speaker 9L is in phase or opposite to each harmful sound and has the same level, so that each harmful sound is canceled in the listener's left ear.

By operating in this manner, the original sound can be heard and noise disturbances can be prevented.

As described above, according to this embodiment, the left and right sub-speakers for canceling harmful reflected sounds are set near the left and right ears of the listener, and a signal for canceling harmful sounds is formed for each path. Since the output is output from the sub-speaker, it is possible to completely eliminate distortions in frequency characteristics due to short time-delayed reflected sounds and wrap-around sounds, and the separation characteristics are greatly improved, resulting in improved sound image localization. There is.

[Effects of the Invention] As explained above, according to the present invention, since the sub-speaker is provided near the correction signal generating means and the listener's ear,
Harmful sounds that affect the sound that is output from the main speaker and directly reaches the listener's ears can be canceled out, thereby completely eliminating distortions in frequency characteristics caused by reflected sounds and wrap-around sounds.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of a sound field correction control circuit used in the embodiment. FIG. 3 is a diagram for explaining the operation of the embodiment. 4 is a block diagram showing a conventional in-vehicle audio device. FIG. 5 is a characteristic diagram explaining the operation of the conventional device. 1...vehicle, 3...acoustic device, 5...amplifier,
α...Sound field correction control circuit, 7R...Right main speaker,
7L...Left main speaker, 9R...Right sub speaker, 9L
...Left sub-speaker.

Claims (1)

[Scope of Claims] In a vehicle-mounted audio device that outputs an original signal supplied from a sound source device as sound from a main speaker, there is no harmful effect on the sound that is output from the main speaker and directly reaches the listener's ears. Comprising a correction signal generating means for generating a correction signal for canceling the sound, and a sub-speaker provided near the listener's ear and outputting a corrected sound from the correction signal generated by the correction signal generating means. An in-vehicle audio device featuring: