JPH08331682A - In-vehicle stereo playback device - Google Patents

Abstract

(57) [Summary] [Purpose] By eliminating the standing wave, the purpose is to eliminate the adverse effects of the standing wave generated in the vehicle interior on the reproduced sound, and to provide excellent reproduced sound with no natural discomfort. And In a vehicle-mounted stereo playback device that performs multi-channel playback with a plurality of speakers, the frequency of the primary standing wave generated in the front-rear direction in the vehicle interior 13 among all band signals applied to the speakers is determined. The band signal A of the included frequency band is reproduced by the speaker 1 installed to perform acoustic emission at the position of the node N of the standing wave, and the low band signal B of a frequency band lower than the band signal A is rear speaker. Played by 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-mounted stereo reproduction apparatus, and a vehicle-mounted stereo reproduction apparatus configured to obtain an excellent reproduced sound by removing a standing wave of a low frequency which adversely affects reproduction sound quality. Regarding the device.

[0002]

2. Description of the Related Art As shown in FIG. 11, a typical and simple configuration of a conventional vehicle-mounted stereo reproducing apparatus is as follows: a left front speaker 4, a right front speaker 5, and a left front speaker 4, a right front speaker 5 and a left front speaker, respectively. A rear speaker 6 and a right rear speaker 7 are arranged, an amplifier 8 is connected to each of these speakers, and a music signal reproducing device 9 such as a tape deck is connected to the amplifier 8. In the vehicle-mounted stereo reproducing device having such a basic structure, acoustic radiation is generated from the front and rear ends of the vehicle interior, so that a primary standing wave having a frequency determined by the longitudinal dimension L of the vehicle interior 13 is generated. Then, as shown in FIG.
In the front and rear ends of the standing wave, the standing wave antinode M is formed, and the sound pressure level in the frequency band rises. As a result, there occurs a phenomenon that the sound pressure level of the frequency band at this portion becomes low.

[0003]

As an influence of this standing wave, in the front seat 14 near the node N of the standing wave, as shown in the sound pressure frequency characteristics of FIG. 9, in the band of 60 to 80 Hz. A dip has occurred, and in the rear seat 15 as a position near the antinode M of the standing wave, the sound pressure level rises in the same frequency band as shown in the sound pressure frequency characteristic of FIG. However, when the reproduced sound is heard in this state, the front seat 14 lacks in low-pitched sound and the sound quality lacks power, and in the rear seat 15, the low-pitched sound portion is emphasized and the intelligibility tends to be poor. There was a drawback in that it was inevitable that the sound quality would be unnatural at any position in the passenger compartment.

Further, the level difference between the front seat 14 and the rear seat 15 in a specific frequency band is large, and the frequency characteristics are different, so that it is very difficult to design the stereo reproduction apparatus in terms of sound quality. There was a point. Therefore, the present invention solves the drawbacks of the above-mentioned conventional example, and adds some improvements to the arrangement of the speakers in the vehicle compartment and the sharing of the reproduction frequency of the signal supplied to the speakers, so that the standing wave generated in the vehicle compartment is reproduced. It is an object of the present invention to eliminate adverse effects and provide an excellent reproduced sound with no natural discomfort.

[0005]

An embodiment of a vehicle-mounted stereo reproducing apparatus according to the present invention for achieving the above object will be described with reference to FIGS. 1 to 4. The first invention is shown in FIG. As described above, in the vehicle-mounted stereo reproducing apparatus for performing multi-channel reproduction by using a plurality of speakers, the band A including the frequency of the primary standing wave occurring in the front-rear direction in the vehicle interior 13 among the signals in the entire reproducing band. The signal is reproduced by the speaker 1 installed to perform acoustic emission at the node N of the standing wave, and the band B signal having a frequency lower than the band A is installed on the rear tray 16. This is a vehicle-mounted stereo reproduction device which is reproduced by the rear speaker 2.

A second aspect of the present invention is the vehicle-mounted stereo reproducing apparatus according to the first aspect of the present invention, wherein the speaker A has a console between the left and right front seats 14, 14 or the front seats 14, 1.
4 Lower or rear door 17 front end, or front door 18
It is a vehicle-mounted stereo reproducing device characterized by being installed at a rear end portion.

The third invention, as shown in FIG. 2, is the first invention described above.
In the vehicle-mounted stereo reproduction device according to the invention, the speaker 1 is installed at an arbitrary location, and a sound conduit 3 opening at a position N of a standing wave is acoustically coupled to the speaker 1. The on-vehicle stereo reproduction device is characterized in that the reproduction sound of the speaker 1 is emitted from the sound conduit 3.

As shown in FIGS. 3 and 4, a fourth invention is the vehicle-mounted stereo reproducing apparatus according to the first invention.
An in-vehicle stereo reproduction device characterized in that an acoustic circuit is added to the speaker 1 to reproduce a band A signal mainly including the frequency of the primary standing wave.

[0009]

In the vehicle-mounted stereo reproducing device having such a structure, since the sound source exists at the position of the node N of the standing wave, the primary standing wave as shown in FIG. 5 does not occur at that frequency.
When the sound source is present at the node N of the standing wave, the sound pressure distribution in the vehicle interior 13 of the standing wave having the lowest frequency is as shown in FIG. 6, and this frequency corresponds to the primary standing wave. (That is, FIG. 5)
(About the frequency when driven at the position of the rear tray 16 shown in FIG. 2). According to the figure, nodes N2 are formed in the front and rear (that is, in the vicinity of the rear seat 15) inside the vehicle compartment 13, and antinodes M2 are formed in the center and front and rear ends of the vehicle compartment 13.

When the frequency becomes higher, the sound is reproduced from another speaker (for example, the front speaker), and there is a reflected sound from another direction. In fact, a clear standing wave as shown in FIG. 6 is generated. Does not occur. Therefore, the influence of the nodes near the rear seat 15 is small. Further, in the vicinity of the front seat 14 when driven at the position of the node N in FIG. 5, that is, at the position of the rear tray 16, there is no dip in the standing wave frequency band due to frequency characteristics, The frequency characteristic becomes almost flat.

A band B signal having a frequency lower than the band A signal is reproduced by the rear speaker 2 installed on the rear tray 16, but at such a low frequency, a standing wave is not generated and the interior of the passenger compartment 13 is not generated. Spread to. Therefore, the passenger compartment 1
In 3 there is no part where the sound pressure level rises abnormally, the frequency characteristics of any part in the passenger compartment 13 become flat, and the unnatural feeling of reproduced sound is eliminated.

As described in the third aspect of the invention, in the type in which the reproduced sound of the band signal A is radiated to the predetermined location by the sound conduit 3,
By utilizing the sound conduit 3 as a resonator, the reproduction efficiency can be increased and the load on the amplifier can be reduced. This is advantageous in reducing distortion in the signal transmission system.

In the case of the type in which the reproduced sound of the band signal A is radiated to a predetermined position by the sound pipe 3, the main body of the speaker 1 can be installed at any place. Therefore, the degree of freedom in designing the size and structure of the main body of the speaker 1 is increased, which facilitates the design.

Further, the band signal A is transmitted to a predetermined position by the speaker 1 described in the fourth aspect of the invention or the sound conduit 3 described in the third aspect of the invention.
When the sound conduit 3 is a resonator of the type that emits the reproduced sound, the band filter in the electric circuit is not necessary when the band signal A is reproduced from the speaker A. Therefore, in implementing the present invention, the cost for extra equipment can be reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of each embodiment will be described in detail with reference to FIGS.
Is a first embodiment, and 13 is a schematic view of a vehicle compartment. In the embodiment shown in the drawing, the left front speaker 4 and the right front speaker 5 are attached to both front sides (side surfaces inside the front door 18) in the vehicle compartment. 14 and 14 are front seats, 15
Is a rear seat, 16 is a rear tray, and 17 is a rear door.

The speaker 1 is attached to the console between the left and right front seats 14, 14, and an electric signal corresponding to the band A obtained through the band filter 10 installed in the electric circuit is supplied to the speaker 1. In this embodiment, the pass band of the band filter 10 is 60 based on the frequency characteristic diagram of FIG.
Although set to ˜80 Hz, when the dimensions of the vehicle interior 13 are different, the primary standing wave frequency determined by the front-rear dimension L of the vehicle interior 13 should be used as a reference.

A rear speaker 2 is installed on the rear tray 16 for the purpose of reproducing a band B signal having a frequency lower than that of the band signal A. Since the directivity of the reproduced low frequency band B signal is broad and does not contribute to the sound image localization, the rear speaker 2 uses only one speaker having a slightly large diameter. Similarly to the speaker 1, the rear speaker 2 is supplied with an electric signal in a frequency band corresponding to the band B signal obtained through the electric low-pass filter 11.

Since signals in the middle, high frequencies higher than the band A signal are related to sound image localization, they are separately supplied to the left front speaker 4 and the right front speaker 5 as in the conventional case.

In the first embodiment, the speaker 1 is attached to the console between the left and right front seats 14, 14, but the position is not limited to this, and the primary standing wave as described above is used. Is near the position where the node N of
They may be installed under the front seats 14, 14 described as the invention, or at the front end portion of the rear door 17 or the rear end portion of the front door 18 toward the inside of the vehicle compartment 13 (both not shown).

Further, as the structure of the speaker 1, for example, by using a bass reflex type speaker device tuned to the frequency of the primary standing wave, the efficiency of the band reproduced by the speaker 1 is increased, and the speaker 1 is miniaturized. Can be reduced or the load on the amplifier can be reduced.

Further, the speaker 1 and the speaker 2,
Also, the reproduced sounds of other mixed speakers reach the listening position with a phase difference. Although not shown, the phase difference may be corrected in an electric circuit.

FIG. 2 shows the configuration of the second embodiment. This embodiment is described as a third aspect of the invention, in which the speaker 1 is installed inside a trunk room 19, and a reproduced sound of the speaker 1 is reproduced by a sound conduit 3 opening at a node N of the standing wave. Is released. In this embodiment, the load of the amplifier can be reduced by increasing the reproduction efficiency by using the sound conduit 3 as a resonator. Further, the main body of the speaker 1 can be installed at any place. Therefore, there is a feature that the degree of freedom in designing the size and structure of the main body of the speaker 1 is increased.

FIG. 3 shows the structure of the third embodiment, and FIG. 4 shows the third structure.
The circuit connections of the example are shown respectively. In this embodiment, speakers 1 and 1 are separately attached to the front end portions of the left and right rear doors 17 and 17 corresponding to the left and right stereo channels, respectively, and the speakers 1 and 1 are obtained through high-pass filters 12 and 12. An electrical signal corresponding to the band A signal is provided. As shown in FIG. 4, the band A signal in this embodiment includes both the primary standing wave frequency and a frequency band higher than that, and is configured in consideration of the sound image localization in the rear seat 15. Has become.

Although not shown in FIGS. 3 and 4,
In the case of this embodiment, an equalizer may be used, if necessary, to increase the level of the primary standing wave frequency to give an effect of enhancing the force of the reproduced sound. Further, in the figure, a bass reflex type speaker device is used as the speakers 1 and 1, and the above-described effect of enhancing the reproduction efficiency and reducing the load of the amplifier is obtained, but the structure is limited to this structure. Instead, it may be a normal vehicle-mounted speaker.

The on-vehicle stereo reproducing apparatus according to the present invention has been described above in detail with reference to a typical embodiment. However, the structure of the on-vehicle stereo reproducing apparatus according to the present invention is not limited to the structure of the above embodiment. However, the present invention can be appropriately modified and implemented as long as it has the constituent features described in the above-mentioned claims, exhibits the action of the present invention, and has the effects described below.

[0026]

[Effect] The vehicle-mounted stereo reproducing device according to the present invention has the following effects. Since the sound source exists at the position of the node N of the standing wave, the standing wave does not occur at that frequency. Therefore,
At the position of the node N, that is, in the vicinity of the front seat, a dip due to a standing wave does not occur on the frequency characteristic, and the frequency characteristic is substantially flat. Therefore, the unnaturalness of the reproduced sound in the front seat is eliminated.

The band B signal having a frequency lower than the primary standing wave described above is reproduced by the rear speaker 2 installed on the rear tray. Such a low frequency does not generate a standing wave and the interior of the passenger compartment Spread to. Therefore, there is no part in the passenger compartment where the sound pressure level rises abnormally. Therefore, the frequency characteristic becomes almost flat in any part of the passenger compartment, and the unnatural feeling of the reproduced sound is eliminated.

As described in the second or third embodiment, the sound conduit D is used as a resonator, or a type such as a bass reflex type that radiates a reproduced sound in a predetermined band by enhancing it by an acoustic circuit is used. By increasing the reproduction efficiency of the speaker 1, the load on the amplifier can be reduced. This is advantageous in reducing distortion in the signal transmission system.

In the case of the type that emits sound through the sound conduit D, the main body of the speaker 1 can be installed at any place. Therefore, the degree of freedom in designing the size and structure of the main body of the speaker 1 is increased, which facilitates the design.

Due to the effects described above, by adopting the speaker arrangement and the reproduction frequency sharing of the vehicle-mounted stereo reproducing apparatus of the present invention, it is simpler than the conventional basic vehicle-mounted stereo reproducing apparatus. By devising and improving the sound pressure distribution in the vehicle interior, it is possible to provide a reproduced sound field that gives a natural and excellent audibility at any listening position.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of a vehicle-mounted stereo reproduction device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a configuration of an installation structure example of the speaker 1 of the second embodiment.

FIG. 3 is a configuration diagram showing a configuration of Example 3 of the same.

FIG. 4 is a connection diagram of a speaker and constituent members of the third embodiment.

FIG. 5 is a basic standing wave sound pressure distribution map when a speaker is installed at the rear end of the vehicle compartment.

FIG. 6 is a basic standing wave sound pressure distribution map when a speaker is installed in the center of the vehicle compartment.

FIG. 7 is a sound pressure frequency characteristic diagram in the front seat of the first embodiment.

FIG. 8 is a sound pressure frequency characteristic diagram in the rear seat of the first embodiment.

FIG. 9 is a sound pressure frequency characteristic diagram in the front seat of the conventional example.

FIG. 10 is a sound pressure frequency characteristic diagram in the rear seat of the conventional example.

FIG. 11 is a configuration diagram showing a configuration of a conventional example.

[Explanation of symbols]

1 Speaker for reproducing a band including the primary standing wave frequency in the vehicle compartment 2 Rear speaker 3 Sound conduit 4 Front left speaker 5 Front right speaker 6 Rear left speaker 7 Rear right speaker 8 Amplifier 9 Music signal reproduction device 10 Band filter 11 Low-pass filter 12 High-pass filter 13 Cabin 14 Front seat 15 Rear seat 16 Rear tray 17 Rear door 18 Front door 19 Trunk room

Claims (4)

[Claims] 1. In a vehicle-mounted stereo reproduction apparatus for performing multi-channel reproduction with a plurality of speakers, all reproduction band signals are generated in the front-back direction in a vehicle compartment (13).
The band A signal including the frequency F of the next standing wave is reproduced by the speaker (1) installed to perform acoustic emission at the position of the node N of the primary standing wave, and the band A signal A vehicle-mounted stereo reproduction device, wherein a signal in a band B having a frequency lower than that of the signal is reproduced by a rear speaker (2) installed in a rear tray (16). 2. The in-vehicle stereo reproduction apparatus according to claim 1, wherein the speaker (1) is provided on the left and right front seats (1).
4), the console between (14), or the front seat (14),
An in-vehicle stereo reproducing device, which is installed under (14), at a front end of a rear door (17), or at a rear end of a front door (18). 3. The in-vehicle stereo reproduction apparatus according to claim 1, wherein the speaker (1) is installed at an arbitrary location, and the sound conduit (3) opens at the node N of the primary standing wave. ) Is acoustically coupled to the speaker (1), and the reproduced sound of the speaker (1) is radiated from the sound conduit (3). 4. The vehicle-mounted stereo reproducing apparatus according to claim 1, wherein an acoustic circuit is added to the speaker (1) to reproduce a band A signal mainly containing the frequency of the primary standing wave. An on-vehicle stereo playback device having a configuration.