JPS6051840B2 - small speaker device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compact speaker device suitable for use in car stereos and the like.

Conventionally, most of the small speaker devices that exist on the market are so-called 2-way systems, which have an enclosure volume of 2 to 2 J and have two speaker units, a woofer and a tweeter, and have the following characteristics: Assuming that they will be used in a very general room, most of them are constructed so that the sound pressure-frequency characteristics, which are the main characteristics for expressing sound field characteristics, are flat in the main frequency range. be.

However, when this kind of speaker device is used in a car stereo, etc., and installed and operated in a passenger car, the sound quality becomes noticeably different compared to when listening in a normal room. .

Possible causes of this are as follows.

That is, the interior of a vehicle such as a passenger car generally has an extremely small volume compared to a normal interior, and many of the interior materials are sound-absorbing, so the reverberation time is extremely short.
In general, the reverberation time inside a car is 0.15 or less at mid-high frequencies, and the value in a normal room is 0.15.
Although it is over 25, it has become considerably shorter. However, the optimal reverberation time when listening to music etc. is 0.
．． It is said to be in the range of 3 to 0.4 seconds.

Therefore, when listening to reproduced sounds such as music inside a passenger car, it is a sound that preserves the direct sound that the listener normally experiences and the indirect sound with an appropriate delay time due to reverberation. This results in a completely different sound, and this manifests itself in a change in the sound quality of the playback sound when listening to a car stereo in the car. As described above, when the conventional small speaker device i is used in a car stereo or the like, it is difficult to reproduce sufficiently satisfactory sound, and it is not possible to obtain so-called high-fidelity sound in a car or the like.

An object of the present invention is to provide a small speaker device that can reproduce a sound field similar to that in a room, and has a sufficient reverberation time even when used inside a passenger car, while eliminating the drawbacks of the prior art described above. In order to achieve this object, the present invention is characterized in that, in addition to the main sound field, a sub-sound field is created by reflection using a window glass surface of a passenger car or the like.

An embodiment of a small speaker device according to the present invention will be described below with reference to the drawings.

Figures 1A, b, and c are top, front, and side views of a speaker device according to an embodiment of the present invention, in which 1 is a top baffle of a speaker enclosure, 2 is a side baffle, and 3 is a front side of the enclosure. , 4 and 5 are the woofer of the bass speaker and the tweeter of the treble speaker provided on the top baffle 1, and 6 is the midrange of the midrange speaker provided on the side baffle 2.

In this embodiment, the top baffle 1 is not horizontal, but is tilted forward by about 20 degrees, and the side baffles are also not perpendicular to the front surface 3, but are tilted forward by about 20 degrees.
ie, at an opening angle of about 110 degrees with respect to the front surface 3.

Further, the side baffle 2 is configured to be perpendicular to the surface of the top baffle 2. This is the most effective when assuming a situation in which the sound waves emitted from the mid-range speaker 6 installed flush with the side baffle 2 are subjected to multiple reflections by the glass surfaces that make up the side surfaces of the car interior. ．． The structure is designed to produce effective multiple reflections. Further, the side baffle 2 has a shape such that the upper baffle 1 is tilted forward at an angle of about 20 degrees from the horizontal plane by shortening one of the four sides. The shape of the side baffle 2 is determined by the mounting. The minimum distance from the center of the middle range 6 to the periphery of the side baffle 2 is larger than the length 112 of one side having the minimum length among the four sides of the side baffle. Figure 2 shows the electrical circuit for the woofer 4, tweeter 5, and midrange speaker 6.The woofer 4 and tweeter 5 are connected to the input terminal 9, crossover network 8, and attenuator. Power is supplied to the mid-range speaker 6 through another input terminal 12 to an attenuator 11,
Power is supplied through a filter 10.

The sound pressure-frequency characteristics based on these are determined as shown in FIG.

That is, the characteristic curve 13 is the sound pressure caused by the woofer 4 and the tweeter 5, and the characteristic curve 14 is the sound pressure caused by the midrange speaker 6. Next, the operation of this embodiment will be explained.

Figure 4 shows the small speaker device A shown in Figures 1 to 3.
, b are installed as a car stereo in a passenger car. Small speaker devices A and b are installed on the rear mount, speaker device Aj is for the right channel, and speaker b is for the left channel. In conventional speaker devices, the sound waves from the speaker devices A and B are mainly transmitted directly to the person C in the driver's seat as sounds 15 and 16, and almost all of them produce reverberant sound due to reflections inside the car. As already explained, in the speaker devices A and b according to this embodiment, the sound quality from the mid-range speaker 6 provided on the side baffle 2 changes. Sound waves are emitted as shown in 17 and 18, reflected multiple times by the window glass on the side of the car body, and reach the ear of person c with an appropriate propagation time delay.

That is, the sound waves from the woofer 4 and tweeter 5 provided on the upper baffle 1 of the speaker devices A and b are reflected by the rear window glass of the car and become direct sound like sound waves 15 and 16, and reach the person c. , the sound waves from the midrange speaker 6 provided on the side baffle 2 are reflected waves 17.
, 18, and reaches person c, and since the propagation distance is long, there is a delay in the propagation time, resulting in reverberant sound.

In Fig. 1, the baffle 1 is tilted forward in order to effectively utilize the reflection from the rear window glass. It does not have to be tilted, but it can be tilted or tilted backwards.

Also, in FIG. 1, the side baffle 2 is located about 20 meters forward
The reason why it is tilted is to make effective use of the reflection from the side window glass of the car, and the angle can be determined as appropriate.

Now, the characteristics of the speaker devices A and b are determined as shown in FIG. That is, the characteristics of the woofer 4 and tweeter 5 are substantially flat in the main frequency range, as shown by curve 13. On the other hand, the characteristics of the mid-range speaker 6 range from about 600Hz to about 3K, as shown by curve 14.
It has almost flat characteristics in the Hz range, and its level is on the second level.
When the amount of attenuation of the attenuator 11 shown in the figure is minimized, it is made to be about a centimeter lower than the characteristic curve 13. In the present invention, roughly speaking, the characteristic curve 13 is the fourth
This is the characteristic of the direct sounds 15 and 16 in the figure, and the characteristic curve 14 corresponds to the reflected sounds 17 and 18. Therefore, if the characteristics are defined as above, the level difference between the direct sounds 15 and 16 and the reflected sounds 17 and 18 will be approximately ωB from the auditory perspective.
In practice, this level of results can often be obtained. However, since there are individual differences in sound quality, it is more preferable to configure the sound quality so that it can be arbitrarily adjusted using the attenuator 11. In addition, the characteristic of the mid-range speaker 6 is set from about 600 Hz to about 3 KHz, as shown in curve 14, because the reverberation time generally increases when the frequency drops below 500 Hz in passenger cars. Sufficient reverberation can be obtained without increasing the number of 17 and 18, and there is generally little reverberation in the high frequency range, especially reflected sound 17 and 18.
This is because even if the number of 18 is increased within this range, there is little practical effect, and this does not indicate that it is necessary to do so in the present invention. Furthermore, in FIG. 2, the input terminals 9 and 12 are provided independently in order to keep the impedance of the speaker device almost constant in the main frequency range.

If the circuit of the midrange speaker 6 is shared with the circuit of the woofer tweeter 5, then the operating frequency range of the midrange speaker 6 will be the same as that of the woofer 4 or the tweeter 5.
The impedance changes in the area where it overlaps. That is, if the impedance of the woofer tweeter 5 and the mid-range speaker 6 is 4Ω, the impedance drops to 2Ω in the overlapping region. Since this is generally not a good thing for a power amplifier, it is simply provided independently as described above.
If there is no problem with this point, input terminals 9 and 1 are not necessarily connected.
It is unnecessary to explain that there is no need to provide 2 separately.

As described above, according to the present invention, when installed inside a car such as a passenger car, a sound field is formed in the car by the direct sounds 15 and 16, and a sound field with a reverberation time is created by the reflected sounds 17 and 18. In other words, it is possible to reproduce sound with reverberation as in a room.

According to actual measurements, when the speaker devices A and b of the present invention are used as shown in FIG. 4, and a general passenger car is used, approximately 10c1B is generated for the direct sound 15, 16 in the mid-range frequency of the reproduced sound. Around low level, and about 10rT1
Reverberant sound with a delay time before and after S is created by the reflected waves 17 and 18, and as a result, the sound quality of the reproduced sound increases in both the sense of spaciousness and richness of the sound field compared to the conventional case, making it more realistic. I was able to give a great impression. As described above, according to the present invention, when used in a car stereo, etc., it is possible to reproduce excellent sound similar to that in a general room, and a high-fidelity car stereo can be obtained. .

In the embodiments shown in FIGS. 1 to 3, the speaker system for forming the main sound field is a two-way system consisting of a woofer and a tweeter, but the present invention is not limited to this, and any type of speaker can be used. It is obvious to those skilled in the art that a combination of two speakers or a single full-range speaker may be used, and it is necessary to explain that this also applies to a mid-range speaker for forming a sub-sound field. 7 will not.

[Brief explanation of the drawing]

FIGS. 1A, b, and c are top, front, and side views of a small speaker device according to an embodiment of the present invention, FIG. 2 is a 9-diagram diagram of an electric circuit for the speaker unit, and FIG. FIG. 4 is also an explanatory diagram of the operation. 1...Top baffle, 2...Side baffle, 3...
- Front of enclosure, 4...woofer, 5...tweeter, 6...mid range speaker.

Claims (1)

[Claims] 1. In a small speaker device for use in a space with a relatively small volume and a short reverberation time, at least one bass speaker is installed flush with the top baffle of the enclosure, and the bass speaker is installed perpendicular to the top baffle surface. At least one midrange speaker is installed flush with a side baffle provided on the side baffle, and the minimum distance from the center position of the midrange speaker to the periphery of the side baffle is determined by , 1/2 of the side with the minimum length
The drive circuit for the mid-range speaker is provided independently from the circuit for driving the bass and treble speakers, thereby creating a sub-sound field independent of the main sound field. A small speaker device.