JP2621052B2 - Recessed vehicle speaker - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-vehicle speaker, and more particularly to an in-vehicle speaker with improved directivity.

[Prior Art] Conventionally, a built-in vehicle-mounted speaker has a full range, and as shown in FIG. 5, a tweeter (high) is provided on a front surface of a diaphragm 22 of a speaker unit UY for bass reproduction via a connecting rod 23. High frequency reproduction) or super tweeter (for ultra high frequency reproduction)
An onboard speaker CS in which a speaker unit TY for reproducing high-pitched sounds is used, and this is connected to a rear tray section at the rear of the vehicle cabin.
Trunk part 31 by mounting in the form embedded in 27
Are arranged so as to use the volume of the speaker cabinet as a speaker cabinet. In the drawing, reference numeral 25 denotes a diaphragm of the speaker unit TY for reproducing high-frequency sound, 26 denotes a rear seat, 28 denotes a rear window, and 32 denotes a ceiling.

[Problems to be Solved by the Invention] Originally, when the in-vehicle speaker is embedded in the rear tray portion 27, the ceiling portion 32 and the rear window portion 28 are located near the speaker.
In particular, reflection and diffusion of high-pitched sound waves occur due to the presence of a wall surface such as a speaker unit.
The sound wave is also emitted in the direction of the ceiling 32, and the high-pitched sound wave is reflected and diffused in the direction indicated by the arrow in the figure.

On the other hand, the listening position is in a positional relationship perpendicular to the vibration direction of the speaker diaphragm, so that the listening position and the direction of the sound wave radiated from the speaker are different, so
Reflection occurs on a wall surrounded by the rear tray 32 and the rear tray 27 and the rear window 28, resulting in disadvantages such as an increase in indirect sound and interference between the indirect sound and the direct sound, thereby deteriorating characteristics.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an in-vehicle speaker capable of overcoming the above-described drawbacks of the related art and making high-frequency sound waves omnidirectional and improving low-frequency sound waves.

[Means for Solving the Problems] An embedded vehicle-mounted speaker according to the present invention comprises a non-directional speaker unit for reproducing high-pitched sounds through a connecting rod at the center of a cone-shaped diaphragm for reproducing low-pitched sounds. In the embedded speaker mounted on the vehicle, the diameter of the connecting rod is increased with distance from the diaphragm for reproducing the bass part, and is formed between the diaphragm for reproducing the bass part and the connecting rod. Is formed in a horn shape that changes with an exponential function or a Bessel function.

In this case, the omnidirectional speaker unit for reproducing the treble portion includes one speaker unit and a reflector having a reflector having the same shape as the diaphragm of the speaker unit. They can be arranged so as to face each other.

We first placed the two acoustic conversion units in opposition so that the diaphragms were as close as possible, and radiated sound waves in the circumferential direction of the diaphragm by driving each acoustic conversion unit in phase. (Japanese Patent Application No. 1-78373) has proposed a loudspeaker system incorporating the omnidirectional acoustic transducer described above. However, the present invention also provides an omnidirectional speaker unit having the above-described configuration as an omnidirectional speaker unit for reproducing high-frequency sound. Speaker unit can be used.

Therefore, the configuration of the omnidirectional speaker unit for reproducing high-pitched sounds used in the present invention is such that two speaker units are arranged so as to face each other so that their diaphragms are close to each other, and both speaker units are in phase. Equipped with a configuration in which sound waves are emitted in the circumferential direction of the diaphragm by being driven, or with one speaker unit and a reflector having the same shape as the diaphragm of the speaker unit, although the characteristics are different from this. This can be realized by using an omnidirectional speaker unit that is configured with a reflector that is arranged in such a manner that the reflector is disposed so as to be close to and opposed to the diaphragm.

The shape of the sound path portion where sound waves are radiated in the circumferential direction of the diaphragm is formed in a horn shape whose cross-sectional area changes by an exponential function or a Bessel function, and furthermore, the overall shape of both opposing speaker units is substantially in cross-section. Make it oval. When the omnidirectional speaker unit is composed of one speaker unit and a reflector, the overall shape of the reflector is substantially the same as that of the speaker unit.

The shape of the connecting rod for mounting the omnidirectional speaker unit for high-frequency sound reproduction is such that the diameter increases as the distance from the low-frequency sound reproduction diaphragm increases. The directivity of low-pitched sound waves can be improved by forming the space formed between the connecting rod and the horn into a horn shape that changes with an exponential function or a Bessel function.

[Operation] When the drive units of the two opposing speaker units are driven in phase, the air in front of both dome-shaped diaphragms is compressed (dense) or sucked (sparse) with each other to generate compressional waves, and the outer peripheral direction (vibration) where the pressure is low The sound wave acts so as to repel air in the circumferential direction of the plate, and the sound waves are efficiently radiated in the circumferential direction of the diaphragm to be non-directional.

When one of the opposing speaker units uses a reflector formed in substantially the same shape as the speaker unit,
Although the characteristics are slightly different, they are similarly omnidirectional.

By mounting the omnidirectional speaker unit for high-frequency reproduction of the configuration as described above to the center axis of the diaphragm for low-frequency reproduction via a connecting rod to constitute an in-vehicle speaker, and embedding and mounting this in the rear tray portion, The sound wave of the treble part is emitted in the horizontal direction (listening position direction), so it matches the listening position,
Unnecessary reflection and diffusion do not occur, and the characteristics do not deteriorate.

[Embodiment] An embodiment of an embedded vehicle-mounted speaker according to the present invention will be described with reference to FIGS. 1 to 4 (A) and (B).

FIG. 1 is a cross-sectional view showing a state in which an embedded vehicle-mounted speaker is mounted on a rear tray portion, FIG. 2 is a cross-sectional view of an omnidirectional speaker unit, and FIG. 3 shows another example of a configuration of an omnidirectional speaker unit. FIGS. 4A and 4B are graphs showing frequency characteristics and directional characteristics.

In the figure, CS indicates the entire embedded speaker mounted on the vehicle, which is mounted on the rear tray 27 so as to be embedded therein, and is arranged so that the trunk 31 is used as a cabinet. This in-vehicle speaker unit CS includes a speaker unit UY for bass reproduction and a speaker unit UY for bass reproduction.
Connecting rod 8 on the central axis (coaxial line) of the cone-shaped diaphragm 22
Speaker unit for treble sound attached via
It is made of TY, but this speaker unit for high-frequency reproduction
TY is configured as an omnidirectional speaker A.

The omnidirectional speaker A is, as shown in FIGS. 1 and 2,
The two speaker units 1 and 2 are arranged facing each other so that the two dome-shaped diaphragms 3 and 4 are close to each other so that they do not touch with the amplitude at the maximum input, and the drive units 1a and 1a of the respective speaker units 1 and 2 2a is connected in series or in parallel and driven in phase to generate compressional waves of air, thereby radiating sound waves in the circumferential direction of the diaphragms 3, 4.

The input signals to the two speaker units 1 and 2 configured as described above have the same phase, and the air on the front surfaces of the two diaphragms 3 and 4 is compressed (dense) or sucked (sparse) with each other, so that the air outside the low pressure is released. And sound waves are efficiently radiated in the horizontal direction in the figure through the sound path section 5 formed between the two speaker units 1 and 2.

As a result, the acceleration of the air is doubled as compared with the conventional single speaker unit, the efficiency of the speaker is doubled, and the two speaker units 1 and 2 have a vibration system interacting with each other as an acoustic load. .

The vibrating plates 3 and 4 are dome-shaped vibrating plates. The sound paths 5 are provided so that sound waves obtained by in-phase driving can be radiated well in the radiation direction.
Is formed in a horn cross section, and the horn wall surface 5a is formed in a symmetrical shape in order to eliminate the influence of the reflection and diffraction phenomena occurring at the exit of the horn. For this reason, the speaker units 1 and 2 are configured such that the overall cross-sectional shape including the frame 6 and the antireflection cover 7 disposed on the back side thereof is substantially elliptical as shown in the figure. 1 and 2 are connected by a support 10. In this way, the two speaker units 1 and 2 are connected by the support columns 10 near the diaphragms 3 and 4.
The vibrations such as the reaction and abnormal resonance generated in 2 can be canceled. In the figures, 1b and 2b are yokes, 1c and 2c are magnets, and 1d and 2d are pole parts.

The sound path section 5 is T (a parameter indicating the spread of the horn)
= 1 ｛(T = 1 is an exponential horn (exponential horn)｝), which is configured to change the cross-sectional area of an exponential horn with a cutoff frequency of 2200 Hz. The horn may have a variable area.

The shape of the connecting rod 8 is not a simple cylinder 8a as shown by a broken line, but is continuously increased in diameter toward the high-pitched sound reproduction speaker unit TY, that is, the cone-shaped diaphragm 22 for low-pitched sound reproduction. The shape is an inverted pyramid so that the diameter increases as the distance from the center part increases. In this embodiment, the connecting rod 8 is shaped like a neck of a horn so that a space formed between the cone-shaped diaphragm 22 and the connecting rod 8 has an exponential function or a Bessel function in cross section. Is configured to form a horn shape that changes, and a cone-shaped diaphragm
The sound path portion 9 formed by 22 and the connecting rod 8 is configured to change the cross-sectional area of the exponential horn having an exponential function of T = 1 and a cutoff frequency of 800 Hz, so that sound waves are efficiently emitted in the listening direction. To be propagated.

FIG. 3 shows an omnidirectional speaker unit A for reproducing high-pitched sound.
FIG. 2 is a diagram showing another configuration of a speaker unit 1 and a reflector 11 having a reflector 13 having the same shape as the diaphragm 3 of the speaker unit 1 and having the same overall shape as the speaker unit 1. The vibration plate 3 and the reflection plate
13 are arranged so as to be close to and opposed to each other. This configuration has no effect such as an increase in air acceleration or efficiency as compared with the speaker unit 1 or 2 opposed type, but can obtain omnidirectionality at low cost.

FIG. 4 (A) shows a 360-degree state of the vehicle-mounted speaker unit CS configured as described above in a standing state (the state of FIG. 1).
The frequency characteristics in the horizontal direction are measured values at a speaker input of 1 watt and a measurement distance of 1 meter. here,
The characteristics in the horizontal direction are the same at any position due to its symmetry. When the omnidirectional speaker unit A is a speaker unit facing type as shown in FIG. 2, the omnidirectional speaker unit A indicated by a solid line V in FIG. 4A is replaced with a reflector arrangement type as shown in FIG. In this case, as shown by the broken line W in FIG. 4 (A), the efficiency was slightly lowered, but uniform frequency characteristics were obtained as in the case of FIG. Therefore, when this is mounted as shown in FIG. 1, the listening position and the radiation direction of the sound wave coincide,
A vehicle-mounted speaker with little deterioration in characteristics is obtained.

FIG. 4 (B) shows the frequency characteristic in the vehicle shown in FIG. 1, which is measured by a speaker input of 1 watt and a measuring distance of 1 meter as in the above example. In FIG. 4B, a solid line X indicates a horizontal plane (driver's seat direction) characteristic, a broken line Y indicates a characteristic of 30 degrees from the horizontal plane, and a dashed line Z indicates a characteristic of 60 degrees.

[Effects of the Invention] According to the embedded image on-vehicle speaker according to the present invention, the following effects can be obtained.

High-frequency sound waves, which are particularly reflected or diffused on the ceiling, rear window, and other reflective walls, are radiated in the horizontal direction, so they can match the listening position, increasing the contact components and increasing the directivity of the speaker This can prevent the deterioration of the high sound quality caused by the noise.

Since the shape of the bottom side and the connecting rod of the speaker unit for reproducing high-pitched sounds is devised, the directivity of low-pitched sound waves can also be improved.

Since the sound path portion has a horn shape, efficiency can be improved, and diffraction and reflection of sound waves can be reduced to obtain good characteristics.

When the omni-directional speaker unit is a speaker unit facing type, the two speaker units facing each other are driven in phase, so the efficiency is doubled, and the vibration corresponding to the driving force is canceled out, so the anti-vibration effect In addition, the two units cancel each other out of the magnetic flux, so that there is an anti-magnetic effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 3 show an embodiment of an embedded vehicle-mounted speaker according to the present invention, and FIG. 1 is a sectional view showing a state in which the embedded vehicle-mounted speaker is mounted on a rear tray portion. , Second
FIG. 3 is a cross-sectional view of an omnidirectional speaker unit, FIG. 3 is a cross-sectional view showing another configuration example of an omnidirectional speaker unit, and FIG.
FIGS. 7A and 7B are graphs showing frequency characteristics and directivity characteristics. FIG. 5 is a sectional view of a conventional embedded type vehicle-mounted speaker. CS: In-vehicle speaker UY: Low-frequency speaker unit TY: High-frequency speaker unit A: Non-directional speaker unit 1, 2: Opposing speaker unit 3, 4: Diaphragm, 5, 9: Sound path section, 8 : Connecting rod, 10: Post 11: Reflector, 22: Vibration plate 27: Rear tray, 28: Rear window 31: Trunk, 32: Ceiling

Claims (2)

(57) [Claims] An embedded in-vehicle speaker in which a non-directional loudspeaker unit for reproducing a treble section is attached to a central portion of a cone-shaped diaphragm for reproducing a low-pitched sound section via a connecting rod. The diameter increases with distance from the bass reproduction diaphragm, and a horn shape in which a space formed between the bass reproduction diaphragm and the connecting rod changes with an exponential function or a Bessel function. Embedded speaker mounted on a vehicle. 2. The omnidirectional speaker unit for reproducing high-pitched sound portions comprises a single speaker unit and a reflector having a reflector having the same shape as a diaphragm of the speaker unit. 2. The embedded vehicle-mounted speaker according to claim 1, wherein the speaker is disposed so as to be opposed to the board.