JPH03214893A - Earphone device - Google Patents

Abstract

PURPOSE:To attain listening to external sound, etc., without detaching an earphone from an ear by mixing an input signal, the negative feedback signal of a signal obtained by an internal microphone unit and the signal obtained by an external microphone unit. CONSTITUTION:A regenerative signal supplied from an input terminal 9 is sound-absorbed by an earphone unit 6 through a variable gain control circuit 10, an adder 13 and an amplifier 14. Voice sound-absorbed by the unit 6 is supplied to a reverse phase circuit 2 through an amplifier 15 and a phase is reversed. The signal whose phase is reversed is supplied to the adder 13 through a variable gain circuit 11 as the negative feedback signal. On the other hand, an external noise signal sound-absorbed by an external microphone unit 7 is supplied to the adder 13 through an amplifier 16 and variable gain control 12. The adder 13 adds and processes the regenerative signal, the negative feedback signal and the external noise signal supplied respectively and supplies an adding signal to the unit 3 through the amplifier 14. The unit 3 converts the adding signal into a voice signal. Thus, reproducing sound whose noise is little can be listened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an earphone device for reducing external noise, which is suitable for use in high noise environments such as inside a vehicle or at a construction site. [Summary of the Invention] The present invention relates to a so-called active type earphone device capable of reducing external noise, which is formed to have approximately the same inner diameter as the external auditory canal, with one end serving as an auricle attachment portion and the other end serving as a non-reflection earphone device for sound. an earphone unit and an internal microphone unit that are mounted close to each other on the peripheral surface of the acoustic tube with their vibration surfaces facing inward of the tube; and an external microphone that is disposed outside the acoustic tube. a mixing circuit that can freely set a variable mixing ratio for mixing an input signal, a negative feedback signal of the signal obtained by the internal microphone unit, a signal obtained by the external microphone unit, and a signal obtained by the internal microphone unit; By changing the mixing ratio of the mixing circuit according to necessity, it is possible to listen to external sounds without removing the earphone device from the ear, and it also reduces the noise reaching the ears from the outside and also reduces the amount of reproduced sound etc. It's like being able to listen to.

[Prior Art] A so-called active type earphone device has been known as an earphone device used for working in places with strong external noise.
As disclosed in the headphones of Publication No. 98, external noise is converted into an electrical signal by a microphone unit,
The noise in the vicinity of the handphone unit was reduced by a negative feedback loop that fed back in an opposite phase.

Also, earphone devices are known that insulate external noise in this manner and allow the user to listen to reproduced sounds such as music without being affected by the external noise.

[Problem to be solved by the invention]

However, the above-mentioned conventional earphone devices have high sound insulation performance and can block out almost all external sounds.
For example, when trying to listen to external sounds such as emergency information or human voices, the earphone device must be removed from the ear, which is very inconvenient.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide an earphone device that allows external sounds to be heard without removing the earphone device being worn.

[Means to solve the problem]

The earphone device according to the present invention includes an acoustic tube formed to have approximately the same inner diameter as the external auditory canal, one end of which serves as an auricle attachment portion, and the other end of which serves as a sound non-reflection end; An earphone unit and an internal microphone unit are mounted close to each other with their vibration surfaces facing inward of the tube, an external microphone unit is placed outside the acoustic tube, and the negative of the input signal and the signal obtained by the internal microphone unit is The above-mentioned i! is characterized by being equipped with a mixing circuit whose mixing ratio can be freely set to mix a feedback signal, a signal obtained by the external microphone unit, and a signal obtained by the internal microphone unit. solve the problem.

(Function) The earphone device according to the present invention includes an acoustic tube formed to have an inner diameter substantially the same as that of the external auditory canal, one end of which serves as an ear attachment portion, and the other end of which serves as a sound non-reflection end. The vibration surfaces of the earphone unit and the internal microphone unit are mounted close to each other on the circumferential surface facing toward the inside of the tube, the external microphone unit is placed outside the acoustic tube, and the mixing circuit is provided, so that the input The negative feedback signal of the signal obtained by the internal microphone unit, the signal obtained by the external microphone unit, and the signal obtained by the internal microphone unit can be mixed at any mixing ratio. [Embodiments] Hereinafter, embodiments of the earphone device according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an earphone device according to the present invention.

In this FIG. 1, the earphone device has an inner diameter W of an external auditory canal A.
It is formed to have an inner diameter W that is approximately the same as that of O, and is provided with an auricle attachment member 4 made of a flexible material such as synthetic resin or rubber at one end, and made of felt, for example, so that the other end serves as a non-reflective end for sound. an acoustic tube l provided with a sound absorbing material 5 such as
an earphone unit 3 and an internal microphone unit 6 that are mounted close to each other with their respective vibration surfaces facing inward of the tube; and the internal microphone unit 6.
an inverted phase circuit 2 which inverts the phase of the internal sound signal inside the sound tube 1 supplied from the sound tube 1 and outputs it as a negative feedback signal; an external microphone unit 7, and a mixing circuit 8 which can variably set a playback signal such as a music signal played from a small portable stereophonic tape recorder or the like, the negative feedback signal, and the external noise signal to an arbitrary mixing ratio. It is made up of.

The mixing circuit 8 includes a variable gain control circuit 10 that varies the gain of the reproduced signal, a variable gain control circuit 11 that controls the gain of the negative feedback signal, and a variable gain control circuit that controls the gain of the external noise signal. 12, and an adder l3 that adds the output signals from the variable gain control circuits 10, 11, and 12, respectively.

The acoustic tube I serves as an earphone housing, and has a uniform inner diameter W and is approximately the same as the inner diameter WO of the external auditory canal A, and a sound absorbing material 5 is provided at the other end so as not to reflect sound. By providing this, the acoustic impedance of the acoustic tube 1 is made to be approximately the same as the impedance of the external auditory canal A, and is configured to prevent the so-called intra-head localization phenomenon. In order to prevent this change in acoustic impedance, the earphone unit 3 and internal microphone unit 6 are arranged so that their respective diaphragms are parallel to the side surface of the acoustic tube 1, and the cross-sectional area S of the acoustic tube 1 is However, the earphone unit 3. Each cross-sectional area S. of the attachment part of the internal microphone unit 6. ．． It is attached so that it is almost the same as S3.

Next, the operation will be explained.

A playback signal supplied via the input terminal 9 from, for example, a small portable stereophonic tape recorder is amplified by an amplifier 14 via a variable gain control circuit 10 and an adder 13, and then sounded by the earphone unit 3. The produced sound is transmitted to the eardrum B via the external auditory canal A, and is collected by the internal microphone unit 6.

The sound picked up by the internal microphone unit 6 is supplied to the anti-phase circuit 2 via the amplifier 15 as an audio signal.

The anti-phase circuit 2 inverts the phase of the supplied audio signal and supplies it to the adder 13 via the variable gain control circuit 11 as a negative feedback signal with the opposite phase.

On the other hand, the external microphone unit 7 collects external noise transmitted to the auditory canal, and this collected external noise is amplified as an external noise signal via the amplifier 16 and sent to the variable gain control circuit 12. The signal is supplied to the adder 13 via the adder 13.

The adder 13 adds the reproduced signal, negative feedback signal, and external noise signal supplied respectively, and supplies the added signal to the earphone unit 3 via the amplifier 14 .

The earphone Uninote 3 converts the supplied addition signal into an audio signal and produces sound.

Here, in the earphone device according to the present invention, the mixing ratio of the reproduction signal, the negative feedback signal, and the external noise signal, which are added in the adder l3 as described above, is adjusted to each of the variable gain control channels 10, 11, and 12. It can be controlled using

In other words, in order to listen to the reproduced signal without being affected by external noise during normal use, the variable gain control circuit 12
The gain of the external sound parking is adjusted to be small or off, and the gain of the reproduction signal adjusted by the variable gain control circuit 10 and the gain of the negative feedback signal adjusted by the variable gain control circuit 11 are adjusted to an arbitrary level. By adjusting the settings, you can hear good reproduced sound with less noise.

On the other hand, if you want to hear emergency information or human voices from outside while listening to such reproduced sound, you can leave the gain adjustment of the reproduced signal and negative feedback signal as is, or reduce or turn off the gain adjustment. By adjusting the variable gain control circuit 12, which has been kept small or turned off, to increase the gain of external noise, emergency information, human voices, etc. from the outside can be heard without removing the earphone device from the ear. can be heard.

In addition, this earphone device produces a substantially silent state by turning off the variable gain control circuit 10 of the reproduced signal and canceling the external noise reaching the eardrum B in the negative feedback loop, and is used as a so-called earplug. Even in this case, by adjusting the gain of the external noise by adjusting the variable gain control circuit 12 as described above, it is still possible to listen to external sounds without removing the earphone device from the ear. .

Note that the gain adjustment of the variable gain control circuit can be performed by operating a switch, a volume control, or the like.

〔Effect of the invention〕

An earphone device according to the present invention includes an acoustic tube formed to have an inner diameter substantially the same as that of the external auditory canal, whose −4 side is an auricle attachment portion, and whose other end is an end that does not reflect sound, and a peripheral surface of the acoustic tube. An earphone unit and an internal microphone unit are mounted close to each other with their vibration surfaces facing inward of the tube, an external microphone unit is placed outside the acoustic tube, and an input signal and an internal microphone unit are provided. and a mixing circuit whose mixing ratio can be freely set to mix the negative feedback signal of the signal obtained by the external microphone unit, the signal obtained by the external microphone unit, and the signal obtained by the internal microphone unit. By varying the mixing ratio of the mixing circuit, it is possible to listen to external sounds without removing the earphone device from the ear, and it is also possible to listen to reproduced sounds while reducing noise reaching the ears from the outside.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of an earphone device according to the present invention. 1...Acoustic tube 2...Reverse phase circuit 3...Earphone unit 4...
......Auricular attachment member 5...
・・・Sound absorbing material 6・・・・・・・・・Internal microphone unit 7
・・・．・・・・・・・・・・・・・External microphone unit 8
......Mixing circuit 9...Input terminal 10.11.12...・Variable gain system'<8 circuit 1
3... Adder Toto 14, 15, 1ε... Amplifier

Claims (1)

[Scope of Claims] An acoustic tube formed to have an inner diameter substantially the same as that of the external auditory canal, with one end serving as an auricle attachment portion and the other end serving as a non-reflecting end for sound; and a vibration surface on the circumferential surface of the acoustic tube. an earphone unit and an internal microphone unit that are mounted close to each other so as to face the inside of the tube; an external microphone unit that is placed outside the acoustic tube; and a negative feedback signal of the input signal and the signal obtained by the internal microphone unit. and a mixing circuit whose mixing ratio can be freely set to mix a signal obtained by the external microphone unit and a signal obtained by the internal microphone unit.