JP3047451B2 - Sound reproduction device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an audio reproducing device used as an earphone device, a headphone device, or a hearing aid.

[Summary of the Invention]

The present invention includes an acoustic tube formed to have substantially the same inner diameter as the ear canal, and a speaker unit mounted on one side surface of the acoustic tube with a sound emitting surface facing the inside of the tube. By providing an auricle-mounted part and the other end as a non-reflective end of sound and providing acoustic resistance control means on the back side of the speaker unit, the sound emitted from the speaker unit reaches the eardrum and is heard. After that, the sound reflected by the eardrum is reflected back to the eardrum side so that it is not heard, and the air on the back of the speaker unit is caused to viscously flow to vibrate the diaphragm constituting the speaker unit. Is controlled so that the lowest reproduction frequency of the speaker unit is lowered and a flat sound pressure frequency characteristic is obtained.

[Conventional technology]

Various types of sound reproducing devices such as a so-called earphone device in which a speaker unit or the like is attached to a human pinna have been proposed, and are widely used for music reproduction and hearing aids.

In this conventional sound reproducing device, for example, when a user hears a sound in an earphone device, a sound reproduced from the speaker unit passes through the earphone housing and the ear canal, reaches the eardrum, and is heard by vibrating the eardrum. .

By the way, in the above-mentioned earphone device and the like, the sound that has reached the eardrum as described above is reflected by the eardrum and then tries to go out of the ear canal. However, in a conventional earphone device or the like, since the earphone housing is attached to the vicinity of the pinna so as to cover the ear canal opening, the sound going to the outside of the ear canal is output from the earphone housing or the speaker unit inside the earphone housing. And is re-entered into the ear canal again toward the eardrum.

Therefore, in the above-mentioned conventional earphone device, the sound directly incident on the eardrum from the speaker unit and the sound once reflected by the eardrum and reflected again by the earphone housing or the speaker unit are heard. When the time interval between these two sounds is less than several hundreds of microseconds, the sound is perceived as a so-called head localization phenomenon or a feeling of oppression.

In order to prevent the sound reflected by the eardrum from being reflected again by the earphone housing or the like,
A sound reproducing apparatus using a sound tube has been proposed in Japanese Patent Application Laid-Open No. 2-86296. That is, the sound reproducing device includes a sound tube formed to have substantially the same inner diameter as the ear canal, and a speaker unit mounted on one side surface of the sound tube with a sound emitting surface facing the inside of the sound tube. One end of the acoustic tube is configured as an auricle mounting portion, and the other end is configured as a non-reflective end of sound. Therefore, in this sound reproducing device, the sound emitted from the speaker unit reaches the eardrum through the sound tube, and is reflected by the non-reflective end side of the sound tube after being heard by the eardrum. It will not be reflected back to the eardrum and heard again.

[Problems to be solved by the invention]

By the way, in such a sound reproducing apparatus, a speaker unit used is such that a diaphragm constituting the speaker unit vibrates in a front direction and a rear direction with respect to a sound output surface, thereby changing the pressure of air to generate sound. It has been made to happen. Therefore, the characteristics of the speaker unit are greatly affected by the state of air existing around the diaphragm.

In the sound reproducing device configured as described above, the back surface of the speaker unit is sealed by a speaker mounting member having a small content. Therefore, air whose flow is restricted exists in the speaker mounting member. This air expands and compresses due to the vibration of the diaphragm constituting the speaker unit and acts as an elastic body on the diaphragm, thereby changing the lowest reproduction frequency of the speaker unit to a higher frequency side.

Therefore, when trying to listen to sound with such a sound reproducing device, since the minimum reproduction frequency of the speaker unit is high, low-frequency sound cannot be obtained and good sound cannot be heard.

In such a sound reproducing apparatus, when the rear side of the speaker unit is opened in order to solve the inconvenience caused by the rear side of the speaker unit being closed, sound leakage occurs outward. In particular, when the hearing aid is configured as a hearing aid, so-called howling or the like occurs due to the sound leaked outward collected by the microphone.

Therefore, the present invention has been proposed in view of such a conventional situation, and after the sound emitted from the speaker unit reaches the eardrum and is heard, the sound reflected by the eardrum is restored. A sound reproducing device that can be reflected to the eardrum side so as not to be heard, and without causing sound leakage to the outside, it is possible to lower the minimum reproduction frequency of the speaker unit and obtain a flat sound pressure frequency characteristic. It has been proposed for the purpose of providing.

[Means for solving the problem]

In order to achieve the above object, a sound reproducing device according to the present invention has an acoustic tube formed to have substantially the same inner diameter as the ear canal, and a sound emission surface facing the inside of the acoustic tube, and one side of the acoustic tube. A speaker unit attached to the speaker unit, one end of the acoustic tube is an auricle mounting part, the other end is a non-reflective end of sound, and an acoustic resistance tube is provided on the back side of the speaker unit. The acoustic resistance control means provided is provided.

[Action]

In the present invention, since the inner diameter of the acoustic tube is substantially the same as that of the ear canal, the acoustic impedance does not change even when the sound reflected by the eardrum goes out of the ear canal through the ear canal and enters the acoustic tube. In addition, since the other end of the acoustic tube is a non-reflective end, the sound that exits the ear canal and enters the acoustic tube is reflected again toward the eardrum at the other end of the acoustic tube. Is prevented.

Further, since the acoustic resistance control means including the acoustic resistance tube is provided on the rear side of the speaker unit, the air on the rear side of the speaker unit viscously flows with the vibration of the diaphragm constituting the speaker unit. Therefore, the diaphragm is not elastically acted on by the air behind the speaker unit, and the speaker unit exhibits a low minimum reproduction frequency. Further, since the vibration of the diaphragm is suppressed to some extent by the viscosity of the air on the back of the speaker unit, the diaphragm does not resonate greatly even at the resonance frequency, and the speaker unit exhibits a flat sound pressure frequency characteristic.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

First, a case where the sound reproducing device according to the present invention is configured as an earphone device will be described with reference to FIG.

This earphone device comprises an acoustic tube (1), a speaker unit (2) mounted with a sound emitting surface (2a) facing the inside of the acoustic tube (1), and an acoustic tube provided on the back side of the speaker unit. Acoustic resistance tube as resistance control means (6)
Is configured as a main component.

The acoustic tube (1) has an inner diameter (W) substantially equal to the inner diameter (Wo) of the ear canal (A). The acoustic tube (1) serves as an earphone housing, and is configured as a long tubular body having a uniform inner diameter (W). The inside of the acoustic tube (1) acts as a sound path, and as described above, the inside diameter (W) of the acoustic tube (1) is made substantially the same as the inside diameter (Wo) of the ear canal (A). This is to make the acoustic impedance of the acoustic tube (1) substantially the same.

If the impedance of the acoustic tube (1) is made substantially the same as the impedance of the ear canal, the impedance of the sound generated when the sound reflected by the eardrum (B) exits through the entrance (C) of the ear canal (A) is obtained. The reflection of the sound due to the change can be prevented, and the sound can be prevented from entering the ear canal (A) again. Therefore, the inner diameter (W) of the acoustic tube (1) may be substantially the same as the average inner diameter of the human ear canal (A). The inner diameter (Wo) of the ear canal (A) of an adult
Is said to be about 7.5 mm. Therefore, if the inner diameter (W) of the acoustic tube (1) is set to 6 mm to 9 mm, the difference in cross-sectional area between the acoustic tube (1) and the entrance of the ear canal (C) can be suppressed to a small level, and the standing wave can be eliminated. And good sound characteristics can be obtained without causing reflected sound to reach the eardrum (B).

On the other hand, the other end of the sound tube (1) is a non-reflection end of sound. That is, the acoustic tube is formed to be somewhat long with the same inner diameter (W). In this way, by making the acoustic tube the same inner diameter and lengthening it to some extent, the reflected sound is attenuated while reaching the other end, thereby preventing reflection occurring at the other end of the acoustic tube. ing.

Next, an auricle attachment member (4) is attached to the acoustic tube (1) so that one end side thereof can be attached to an entrance (C) of an ear canal (A). The auricle attachment member (4) is formed of a flexible synthetic resin or rubber material to improve the feeling of attachment to the auricle (D). The inner diameter of the mounting member (4) is also set so as not to change the characteristic of the acoustic impedance in the acoustic tube.

Then, the speaker unit (2) is mounted on one side of the acoustic tube (1) such that the sound emission surface (2a) faces the inside of the tube.
The speaker unit (2) is desirably mounted so that the inner diameter (W) of the acoustic tube (1) is not changed so as not to disturb the impedance of the acoustic tube (1).

The speaker unit (2) includes a diaphragm, a voice coil that vibrates the diaphragm, and a magnetic circuit as main components. That is, a drive current corresponding to the acoustic signal is supplied to the voice coil, and the diaphragm is driven in the front and rear directions with respect to the speaker sound emitting surface (2a) to reproduce sound.

In this earphone device, an acoustic resistance tube (6) serving as acoustic resistance control means is provided on the back side of the speaker unit (2). This acoustic tube resistance tube (6)
Is open at the end opposite to the speaker unit,
It is formed to be somewhat long, and the air on the rear side of the speaker viscously flows by the vibration of the diaphragm. Therefore, the diaphragm is not elastically acted on by the air behind the speaker unit (2), and its vibration is suppressed to some extent by the viscosity of the air behind the speaker unit (2). Absent. Then, as shown by the solid line (A) in FIG. 2, the lower reproduction frequency of the speaker unit (2) is lowered and a flat sound pressure frequency characteristic is realized. In FIG. 2, the dotted line (B) indicates the sound pressure frequency characteristics of the speaker unit in which the acoustic resistance tube (6) is not provided on the back side.

Further, the acoustic resistance tube (6) serving as acoustic resistance control means attenuates the sound emitted to the back side of the speaker unit (2), so that the standing wave on the back side of the speaker unit (2) is reduced. Can be suppressed.

In the sound reproducing apparatus configured as described above, the sound reflected by the eardrum is not reflected again and is not heard, and the speaker unit (2) has a low minimum reproduction frequency and a flat sound pressure frequency. Because of the characteristic, a clear and high-fidelity sound is heard.

Further, in order to achieve further downsizing of the sound reproducing device, a sound absorbing material may be arranged in the sound tube and the acoustic resistance tube.

That is, as shown in FIG. 3, this earphone device is similar to the above-mentioned earphone device, and has a sound tube (1) and a speaker unit (2) and a speaker unit which are mounted inside the sound tube with a sound emitting surface facing the inside. And an acoustic resistance tube (6) provided on the back side of.

In this earphone device, a sound absorbing material such as a porous material or a cotton-like member is provided at the other end of the acoustic tube (1) and at one end of the acoustic resistance tube (6) opposite to the speaker unit (2). Materials (5) and (7) are provided. That is, the sound absorbing materials (5) and (7) realize the sound attenuation at an early stage.

Therefore, in the sound reproducing apparatus thus configured, even if the lengths of the sound tube (1) and the acoustic resistance tube (6) are shortened, the sound reflected by the eardrum is reflected again as in the above-described earphone device. Without being heard,
The lower reproduction frequency of the speaker unit (2) can be lowered and a flat sound pressure frequency characteristic can be realized. That is, the size of the earphone device can be reduced.

Further, the sound reproducing device according to the present invention can also be applied to a hearing aid.

An example in which the hearing aid is configured as an ear-hearing hearing aid will be described with reference to FIG. 4. First, an acoustic tube (1) and an acoustic resistance tube (6) are provided on the outer periphery of an auricle (D) within a range that does not affect acoustic impedance. Bend along the shape. At this time, the speaker unit (2) is attached to a part of the acoustic tube (1) such that the sound emission surface does not face the eardrum. That is, the generation of a standing wave caused by the repeated reflection of the reproduced sound between the eardrum and the diaphragm of the speaker unit (2) is prevented.

Next, the microphone (8) is located near the auricle (D) so as to collect sound very similar to the sound collected by the auricle (D). Attach to a part of (6).

In the hearing aid configured as shown in FIG. 4, the sound collected by the microphone (8) is:
The sound is converted into an acoustic signal by the microphone (8). The acoustic signal is supplied to a speaker unit (2) via an amplifying device or the like (not shown). When the speaker unit (2) is driven, the sound collected by the microphone (8) is externally transmitted. Sound is emitted into the ear canal via the acoustic tube (1).

When this sound reproducing device is configured as a hearing aid, if a sound absorbing material is used at the end of the acoustic resistance tube (6) opposite to the side on which the speaker unit (2) is arranged, the rear surface of the speaker unit (2) can be used. The reproduced sound emitted from the speaker unit (2) can be further attenuated, and the reproduced sound emitted from the speaker unit (2) is prevented from being collected by the microphone (8). It is possible to prevent howling occurring between the microphone and the microphone (8).

In the case where the sound reproducing apparatus according to the present invention is configured as a hearing aid, the microphone (8) is provided with the microphone (8) as described above in order to achieve sound collection that is more similar to the sound actually collected by the pinna. When the hearing aid is attached to the pinna, it is desirable to provide the hearing aid at a position close to the eardrum.

Therefore, as shown in FIG. 5, when the hearing aid is attached to the auricle (D), it is desirable that the microphone (8) is arranged so as to be located in the concha of the auricle (E). . That is, when the hearing aid is attached to the auricle, the microphone (8) is located at the entrance (A) of the external auditory canal (A) of the acoustic tube (1) so as to be located in the concha (E) of the auricle (D). It is attached to the outer peripheral surface of the vicinity position inserted in C). By providing the microphone (8) in this way, sound collection similar to the sound actually collected by the pinna is realized, and a realistic hearing aid function can be realized.

〔The invention's effect〕

As is clear from the above description, according to the present invention,
Since the inner diameter of the acoustic tube is substantially the same as that of the ear canal, it is possible to prevent a change in impedance due to sound reflected by the eardrum being emitted from the ear canal to the outside of the ear canal.

Further, since the other end of the acoustic tube is a non-reflective end, it is possible to prevent the sound emitted outside the ear canal from being reflected back to the eardrum.

Therefore, when the sound source is viewed from the entrance of the external auditory canal, reflection from the earphone housing and the pinna on the sound source side can be prevented from occurring, and the in-head localization phenomenon and the feeling of oppression in the auditory sense during listening can be prevented. be able to.

Further, since the acoustic resistance control means including the acoustic resistance tube is provided on the back side of the speaker unit, the vibration of the diaphragm constituting the speaker unit is controlled. It is possible to realize a high sound pressure frequency characteristic.

Therefore, according to such a sound reproducing device, a clear and high-fidelity sound can be heard, and in the case of a hearing aid, a sound faithful to an external sound can be heard. .

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example in which the sound reproducing device according to the present invention is used as an earphone device. FIG. 2 is a sound pressure frequency characteristic diagram of a speaker unit constituting the sound reproducing device according to the present invention. FIG. 3 is a schematic sectional view showing another example in which the sound reproducing device according to the present invention is used as an earphone device. FIG. 4 is a perspective view showing an example in which the sound reproducing device according to the present invention is applied to a hearing aid, and FIG. 5 is a perspective view showing another example of the hearing aid. DESCRIPTION OF SYMBOLS 1 ... Acoustic tube 2 ... Speaker unit 4 ... Mounting member 6 ... Acoustic resistance tube 8 ... Microphone

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Claims (1)

(57) [Claims] 1. An acoustic tube having substantially the same inner diameter as an ear canal, and a speaker unit mounted on one side of the acoustic tube with a sound emitting surface facing the inside of the acoustic tube. One end of the acoustic tube is used as an auricle attachment portion, the other end is a non-reflection end of sound, and an acoustic resistance control means including an acoustic resistance tube is provided on the back side of the speaker unit. Sound reproduction device.