WO2012042672A1

WO2012042672A1 - Noise-cancelling headphones

Info

Publication number: WO2012042672A1
Application number: PCT/JP2010/067270
Authority: WO
Inventors: 雅昭野吹; 善照内田
Original assignee: フォスター電機株式会社
Priority date: 2010-10-01
Filing date: 2010-10-01
Publication date: 2012-04-05

Abstract

[Problem] To achieve feed-forward-type, in-ear-style noise-cancelling headphones capable of reducing variation between individuals in the noise cancellation effect. [Solution] In-ear-style noise-cancelling headphones are provided with: a microphone unit for collecting ambient noise; a driver unit for converting inputted electric signals into sound; a housing for accommodating the microphone unit and the driver unit; and a cylindrical sound channel that guides the sound formed in the driver unit to the external auditory canal, and is provided in the inner tip of the housing. The in-ear-style noise-cancelling headphones are further provided with a ventilation duct for connecting the interior of the external auditory canal and a ventilation opening provided at a location in the housing that is outside the external auditory canal.

Description

Noise canceling headphones

The present invention relates to a noise canceling headphone having a feedforward type noise canceling function, and relates to a technique for eliminating a difference in noise canceling effect caused by a difference in sealing between an earpiece and an external auditory canal when the noise canceling headphone is used.

Headphones generate air density waves by vibrations of a diaphragm in a driver unit housed in a housing, and generate a sound corresponding to an electric signal. In particular, the insert type headphones have advantages such as high efficiency and little influence of ambient sound because the sound is directly transmitted while being inserted into the ear canal entrance by the earpiece.

On the other hand, the headphone is equipped with a microphone unit to collect ambient sounds, predict the phase and level of the transmitted sound reaching the eardrum from the ambient sound, and generate a cancellation sound with the opposite phase to the transmitted sound. There is a so-called noise canceling headphone to cancel.

As this type of noise canceling headphones, those described in the following patent documents are known.

Japanese Patent Laid-Open No. 3-214892 JP 2008-67035 A

Insert type headphones have advantages such as high efficiency and low influence of ambient sound because they transmit sound directly with the earpiece inserted into the ear canal entrance.

By the way, the insert type headphones have a problem that individual differences occur in the sealing condition between the earpiece and the ear canal due to the difference in the degree of insertion of the earpiece into the ear canal.

And, it is known that in the insert type headphones, the frequency characteristics reproduced in the ear canal greatly change due to such individual differences in the sealing condition. When the frequency characteristic reproduced in the ear canal changes in this way, the cancellation signal is constant, and thus a difference occurs in the noise cancellation effect.

In this case, in the noise canceling headphones, individual differences occur in the characteristics of transmitted sound (hereinafter referred to as transmitted sound characteristics) due to such individual differences in sealing. The “transmitted sound” means a sound that passes through an obstacle such as an earphone and reaches the ear canal from the outside. In addition, if there is a leaking sound that passes through the gap between the earpiece and the ear canal due to individual differences in the degree of sealing between the earpiece and the ear canal, it is treated as a transmitted sound, including this leaking sound. . The “transmitted sound characteristic” is a frequency characteristic of sound that passes through an obstacle such as an earphone and reaches the ear canal from the outside. When the transmitted sound characteristic changes as described above, the cancellation signal is constant, and thus a difference occurs in the noise cancellation effect.

It should be noted that it is possible to prepare a larger number of earpieces that combine large, medium, and small differences with respect to the diameter and depth of the external auditory canal so that there is no individual difference in the sealing condition. However, in this case, there is a problem that each individual has to select a suitable one from among a large number of earpieces, and there is a problem that it cannot be dealt with until the degree of insertion is insufficient.

On the other hand, instead of simply generating a cancellation signal with the feed forward method, a microphone unit is installed in the ear canal and the feedback method is used to cope with various factors so that the noise cancellation effect does not change. Can be configured. However, the circuit configuration becomes complicated and power consumption increases, which makes it unsuitable for portable or small noise-canceling headphones.

The present invention has been made to solve the above-described problems, and is intended to realize a feedforward type insert type noise canceling headphone capable of reducing individual differences in noise canceling effects. Objective.

The present invention that solves the above problems is as described below.

(1) The present invention is generated by a microphone unit that collects ambient sounds, a driver unit that converts input electric signals into sound, a housing that houses the microphone unit and the driver unit, and the driver unit. A cylindrical portion provided in the housing so as to constitute a sound path that guides the sound into the external auditory canal, and an earpiece that is configured of a material having flexibility so as to be in contact with the inner surface of the external auditory canal and disposed around the cylindrical portion; An insert type noise canceling headphone comprising: a ventilation opening provided outside the ear canal and at any position of the housing; and a ventilation duct for communicating the ventilation opening with the inside of the ear canal And.

(2) Here, the ventilation duct is configured as a part of the cylindrical portion, and has a space independent from the sound path as a ventilation path.

(3) Here, the ventilation duct is configured to be provided in parallel with the sound path in the cylindrical portion.

(4) Here, a breathability adjusting material for adjusting breathability between the ventilation opening and the ear canal is provided at any position of the ventilation duct.

(5) Here, a plurality of the ventilation openings are provided at any position of the housing with respect to one ventilation duct.

According to the present invention, the following effects can be obtained.

(1) In the insert type noise canceling headphones, since the sound is directly transmitted with the earpiece inserted into the ear canal entrance, there are advantages such as high efficiency and less influence of ambient sounds. There may be a difference in the sealing between the earpiece and the external auditory canal due to differences in cross-sectional shape or the degree of insertion, etc., but the ventilation opening provided in any position of the housing outside the external ear canal and in the external auditory canal Are connected to each other by a ventilation duct, and the ventilation characteristic is changed, and the frequency characteristic is changed in advance from the sealed state by the ventilation condition.

Here, since the ventilation through the ventilation duct is in a state close to a decrease in the sealing condition, even if there is a difference in the sealing condition between the earpiece and the external auditory canal, the change in the transmitted sound characteristics becomes small and reproduction in the external auditory canal The frequency characteristics to be applied do not change greatly.

In other words, the earpiece was inserted into the ear canal when wearing noise-cancelling headphones by connecting the eardrum, the ear canal, the earpiece, and the space (sealed space) enclosed by the tip filter to the outside through a ventilation duct provided near the sound path. Even if there are individual differences in the size and shape of the ear hole and the external auditory canal, the difference in the amount of air leaking from the gap generated between the earpiece and the external auditory canal is stabilized, thereby stabilizing the noise canceling effect.

As a result, it is possible to realize a feed forward type insert type noise canceling headphone that does not cause a large fluctuation in the noise canceling effect without adopting a feedback method.

(2) Here, since the ventilation duct has a space independent of the sound path as a ventilation path, it is possible to independently adjust the acoustic characteristics of the sound path and the ventilation of the ventilation duct. Even if there is a difference in the sealing condition with the sound, it is possible to reduce the change in transmitted sound characteristics, and to realize feed-forward type insert type noise cancellation headphones that do not cause large fluctuations in the noise cancellation effect Can do.

(3) Here, since the ventilation duct is configured to be parallel to the sound path in the cylindrical portion, the sound path and the ventilation duct can be independently configured and adjusted. Even if there is a difference in the sealing condition with the sound, it is possible to reduce the change in transmitted sound characteristics, and to realize feed-forward type insert type noise cancellation headphones that do not cause large fluctuations in the noise cancellation effect Can do.

(4) Here, even if there is a difference in the sealing condition between the earpiece and the ear canal by providing a breathability adjusting material in any position of the ventilation duct and adjusting the air permeability between the ventilation opening and the ear canal The change in transmitted sound characteristics is small, and even if there is a difference in the sealing condition between the earpiece and the ear canal during use, the frequency characteristics reproduced in the ear canal will not change greatly, and the noise canceling effect will be great. It is possible to realize a feed forward type noise canceling headphone that does not cause fluctuation.

(5) Here, a plurality of ventilation openings are provided at any position of the housing with respect to one ventilation duct, and the plurality of ventilation openings and the inside of the ear canal are made to be in a ventilation state by the ventilation duct. No matter how the sealing condition between the earpiece and the external auditory canal changes, the level and phase change of the transmitted sound reaching the eardrum will be small, and the noise canceling effect will not vary greatly.

It is sectional drawing which shows the cross-sectional structure of the noise cancellation headphones of embodiment of this invention. It is a disassembled perspective view which shows the mode of each component of the noise cancellation headphones of embodiment of this invention. It is a characteristic view which shows the frequency characteristic of insert type noise cancellation headphones. It is a characteristic view which shows the frequency characteristic of insert type noise cancellation headphones. It is a front view which shows the structure of the noise cancellation headphones of embodiment of this invention. It is a block diagram which shows the cross-sectional structure of the noise cancellation headphones of other embodiment of this invention.

Hereinafter, the best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings.

[First embodiment]
[Configuration of First Embodiment]
FIG. 1 is a configuration diagram showing a cross-sectional configuration of a noise canceling headphone 100 having a noise canceling function according to the first embodiment of the present invention. FIG. 2 is an exploded perspective view showing an exploded state and an assembled state of each part of the noise cancellation headphone 100 of the first embodiment.

1 and 2, the driver unit 101 that generates sound by vibrating the diaphragm in accordance with the input electrical signal is centered on the outer side of the cylinder constituting the sound path serving as the sound outlet. A front housing 110F having a portion 110P at the projecting end and constituting a front side housing; a back housing 110B as a rear side housing while securing a back space; a microphone unit 102 that is held by the back housing 110B and collects ambient sounds; A ring 110R provided between the housing 110F and the back housing 110B, and a cover 110Cv for securing a back space and holding a cable (not shown) are provided. In these figures, the sound output direction is the front and the opposite side is the back.

It should be noted that a back filter 101BF is provided on the back side of the driver unit 101 in order to brake the vibration of the diaphragm. The back filter 101BF is configured in a C shape instead of a ring shape in order to avoid a contact portion of the driver unit 101.

Further, on the front side of the driver unit 101, an opening 101FH is provided in the front housing 110F, and a front filter 101FF is provided between the driver unit 101 and the opening 110FF.

Further, around the vicinity of the tip of the cylindrical portion 110P, an earpiece 120 made of silicon rubber or the like is attached so as to be fitted into the ear canal.

In addition, the inside of the cylindrical portion 110P is divided and most of the sound path 130 serves as an outlet for sound from the driver unit 101, and ventilation as an independent ventilation path in a form parallel to the sound path 130. A duct 140 is provided.

Here, the sound path 130 is a transmission means (acoustic transmission path) for guiding the sound from the driver unit 101 into the ear canal.

On the other hand, the ventilation duct 140 is a conduction means for maintaining a ventilation state by communicating the ventilation opening 140a provided outside the ear canal and at any position of the front housing 110F with the inside of the ear canal. Here, the ventilation opening 140a is provided at any position near the front housing 110F of the cylindrical portion 110P, that is, outside the ear canal when the noise cancellation headphones 100 are used.

In addition, although the ventilation opening part 140a may be single, as shown in FIG. 5 described later, a plurality of ventilation opening parts 140a are provided at any position of the front housing 110F with respect to one ventilation duct 140. Also good.

Here, since the air duct 140 has a space independent from the sound path 130 as a ventilation path, the acoustic characteristics of the sound path 130 and the air permeability of the air duct 140 can be adjusted independently. Even if there is a difference in the sealing between the external ear canal and the ear canal, the change in transmitted sound characteristics can be reduced.

And the air permeability adjustment material 140F which adjusts air permeability between the ventilation opening 140a and the ear canal is provided on the ear canal side of the ventilation duct 140. In addition, this air permeability adjustment material 140F is comprised by the member which has air permeability, such as sponge, and should just be provided in the position of the ventilation duct 140. FIG.

Further, on the output side of the sound path 130 and the ventilation duct 140, that is, on the vicinity of the tip of the cylindrical portion 110P, a tip filter 110TF for preventing foreign matter from being mixed is provided.

[Description of First Embodiment]
In the above configuration, the insert type noise canceling headphones 100 are used in a state where the earpiece 120 is fitted in the ear canal. At this time, the diaphragm vibrates according to the electric signal supplied to the driver unit 101, and a sound is generated. The sound from the front of the driver unit 101 reaches the eardrum from the external auditory canal via the sound path 130 and the tip filter 110TF.

Furthermore, the noise canceling headphones 100 have a noise canceling function. The microphone unit 102 collects ambient sounds, predicts the phase and magnitude of the transmitted sound reaching the eardrum from the ambient sound, and has an opposite phase to the transmitted sound. A cancel signal is generated so that the sound reaches the eardrum, and the surrounding sound is canceled by reproducing the cancel signal.

Here, due to the difference in the cross-sectional shape of the earpiece 120 and the cross-sectional shape of the ear canal, and the difference in the degree of insertion of the earpiece 120 into the ear canal, there may be a difference in the sealing condition between the earpiece 120 and the ear canal.

FIG. 3 shows frequency characteristics in the ear canal when headphones (comparative examples) to which the present embodiment is not applied are worn. The horizontal axis represents frequency f [Hz] and the vertical axis represents sound pressure P [dB]. Is shown.

Here, FIG. 3A is a characteristic diagram showing an example of frequency characteristics in the external auditory canal of the noise canceling headphone 100 in a state where the earpiece 120 and the external auditory canal are satisfactorily sealed, that is, in a state where the sound insulation state is good. FIG. 3 (3) is a characteristic diagram showing an example of frequency characteristics in the ear canal of the noise canceling headphone 100 in a state where the sealing condition between the earpiece 120 and the ear canal is lowered, that is, in a state where the sound insulation state is not good. FIG. 3 (2) shows the frequency in the ear canal of the noise canceling headphone 100 when the earpiece 120 and the ear canal are sealed or sound-insulated in the middle state between FIG. 3 (1) and FIG. 3 (3). It is a characteristic view which shows an example of a characteristic. That is, in the case of this specific example, the sound pressure P has a difference in the low frequency characteristics within the ear canal due to the difference in sealing between the earpiece 120 and the ear canal.

It should be noted that the state of good sealing between the earpiece 120 and the ear canal means that the cross-sectional shape of the earpiece 120 and the cross-sectional shape of the ear canal are the same, and the degree of insertion of the earpiece 120 into the ear canal is appropriate. There is no gap between the earpiece 120 and the earpiece 120 and the ear canal. On the other hand, the state in which the sealing state of the earpiece 120 and the external auditory canal is reduced is that the cross-sectional shape of the earpiece 120 and the cross-sectional shape of the external auditory canal do not match or the insertion degree of the earpiece 120 into the ear canal is shallow. There is a gap between the earpiece 120 and the ear canal, or there is no gap between the earpiece 120 and the ear canal.

Here, when the level of the cancel signal is adjusted in accordance with the state of FIG. 3 (2), the level of the cancel signal becomes excessive in the state of FIG. 3 (1), and the external sound is amplified and heard. . Further, when the level of the cancel signal is adjusted in accordance with the state of FIG. 3 (2), the level of the cancel signal becomes too low in the state of FIG. 3 (3), and the noise canceling effect is insufficient.

FIG. 4 shows the inside of the external auditory canal when the present embodiment is applied and the noise canceling headphone 100 having the ventilation duct 140 as a conduction means for keeping the outside of the external auditory canal and the inside of the external auditory canal in a ventilation state is mounted. The horizontal axis represents the frequency f [Hz], and the vertical axis represents the sound pressure P [dB].

Here, FIG. 4A is a characteristic diagram showing an example of frequency characteristics in the ear canal when the noise canceling headphones 100 are worn in a state where the earpiece 120 and the ear canal are relatively well sealed. On the other hand, FIG. 4 (3) is a characteristic diagram showing an example of the frequency characteristic of the noise canceling headphone 100 in a state where the sealing condition between the earpiece 120 and the ear canal is lowered. FIG. 4 (2) shows the frequency in the ear canal of the noise canceling headphone 100 when the sealing condition and sound insulation between the earpiece 120 and the ear canal are intermediate between those shown in FIG. 4 (1) and FIG. 4 (3). It is a characteristic view which shows an example of a characteristic.

In this case, although it is an insert type noise canceling headphone 100 in which the earpiece 120 and the ear canal are brought into close contact with each other, the outside of the ear canal and the inside of the ear canal are kept in a ventilation state by the ventilation duct 140.

For this reason, as shown in FIGS. 4 (1) to (3), the fluctuation of the sound pressure P in the frequency characteristic varies even when the sealing condition between the earpiece 120 and the ear canal is good or low. It is smaller than the conventional one (see FIG. 3 of the comparative example).

Here, when the level of the cancel signal is adjusted in accordance with the state of FIG. 4 (2), the difference in the level of the cancel signal in FIG. 4 (1) and FIG. 4 (3) is shown in FIG. Compared to this, it is smaller and almost appropriate noise cancellation is performed.

Therefore, even if the sealing condition between the earpiece 120 and the external auditory canal changes, the noise canceling headphone 100 of the present embodiment has a smaller noise canceling effect than the comparative example shown in FIG.

Therefore, even when a cancel signal is simply generated by the feedforward method, a good noise canceling effect with small fluctuations in the effect can be obtained. As a result, the feedback method becomes unnecessary.

Furthermore, even when the transmitted sound reaches the eardrum from the outside through a portion where the sealing condition between the ear canal and the earpiece 120 is lowered, there is already ambient sound entering through the ventilation duct 140. The level of the transmitted sound reaching the eardrum and the change in the phase do not change so much, and the noise canceling effect is not greatly reduced even when the sealing condition is good. It should be noted that the generation of the cancel signal on the premise of the presence of the ambient sound that enters through the ventilation duct 140 in this way can avoid a reduction in the original noise cancellation effect.

That is, the space (sealed space) surrounded by the eardrum, the ear canal, the earpiece 120, and the tip filter 110TF is communicated with the outside through the ventilation duct 140 provided in the vicinity of the sound path 130, so that the earpiece 120 is attached when the noise canceling headphones are attached. Stabilizes the noise canceling effect by stabilizing the difference in the amount of air leaking from the gap between the earpiece 120 and the ear canal due to individual differences in the size and shape of the ear hole and ear canal when the is inserted into the ear canal I am letting.

By doing so, the noise cancellation effect can be greatly varied without adopting a feedback method, without relying on the selection of many earpieces with different diameters and lengths, and without being affected by the difference in the degree of earpiece insertion. Therefore, it is possible to realize a feed-forward type insert-type noise canceling headphone that does not cause noise.

Further, since the ventilation duct 140 has a space independent of the sound path 130 as a ventilation path, the acoustic characteristics of the sound path 130 and the ventilation property of the ventilation duct 140 can be adjusted independently. Even if there is a difference in the sealing condition with the ear canal, it is possible to reduce the change in transmitted sound characteristics and realize a feed-forward type insert type noise cancellation headphone that does not cause large fluctuations in the noise cancellation effect. be able to.

Further, since the ventilation duct 140 is configured to be parallel to the sound path 130 in the cylindrical portion 110P, the sound path 130 and the ventilation duct 140 can be independently configured and adjusted, and the earpiece is adjusted. Even if there is a difference in the sealing between 120 and the external auditory canal, it is possible to reduce the change in transmitted sound characteristics, and feed-forward type insert type noise cancellation headphones that do not cause large fluctuations in the noise cancellation effect Can be realized.

Further, in the frequency characteristic of FIG. 4 (1), the sound pressure of 100 Hz or less is reduced due to the influence of the ventilation duct 140 as compared with the frequency characteristic of FIG. 3 (1). However, since the final frequency characteristic of the noise canceling headphones 100 can be set to a desired characteristic by adjusting each part, the low-frequency sound pressure is not insufficient by applying this embodiment.

In addition, in the frequency characteristic diagram shown in FIGS. 3 and 4 due to a change in the sealing condition between the earpiece 120 and the external auditory canal, in which frequency region the variation occurs, how much the variation range changes, and in which frequency region It is possible to adjust whether the fluctuation is eliminated or how much the fluctuation range is eliminated by adjusting the cross-sectional area of the ventilation duct 140 and adjusting the air permeability by the air permeability adjusting material 140F. is there.

FIG. 5 is an explanatory diagram for explaining the ventilation opening 140a. Here, as shown in FIG. 5A, the ventilation opening 140a is located at any position on the side close to the front housing 110F of the cylindrical portion 110P, that is, at a position outside the ear canal when the noise canceling headphones 100 are used. Is provided.

In FIG. 5 (a), two ventilation openings 140a are provided and connected to the ventilation duct 140 inside, and the outside of the external auditory canal and the inside of the external auditory canal are kept in a vented state. In FIG. 5B, three ventilation openings 140a are provided and connected to the ventilation duct 140 to keep the outside of the ear canal and the inside of the ear canal in a vented state.

Here, when the sealing condition between the ear canal and the earpiece 120 is lowered, the surrounding sound may reach the eardrum as a gap leak sound through a portion where the sealing degree is lowered. Therefore, in order to reduce the influence of such ambient sounds, the ventilation opening 140a is positioned in a plurality of different directions of the cylindrical portion 110P so that the sealing degree of any part of the earpiece 120 and the ear canal may be lowered. It is desirable to provide in.

Note that an electronic circuit that generates a cancellation signal having a phase opposite to that of the ambient sound collected by the microphone unit 102 and adds it to the sound signal to be reproduced may be incorporated in the noise cancellation headphones 100 or the noise cancellation headphones 100. May exist outside of.

[Second Embodiment]
In the first embodiment described above, the canal type noise canceling headphone 100 in which the outer diameter of the front housing 110F is larger than the diameter of the earpiece 120 is shown as a specific example. However, in the second embodiment, the diameter of the earpiece 120 and the front A canal type noise cancellation headphone 100 in which the outer diameters of the housings 110F are substantially equal is shown as a specific example.

Here, FIG. 6 is a configuration diagram showing a cross-sectional configuration of the canal type noise canceling headphones 100 of the second embodiment. In addition, the same number is attached | subjected to the same thing as FIG. 1, and the overlapping description is abbreviate | omitted.

In the case of FIG. 6 as well, the driver unit 101 that generates sound by vibrating the diaphragm according to the input electrical signal is centered, and on the outer side, the cylindrical portion 110P constituting the sound path serving as the sound outlet is provided. A front housing 110F that constitutes a front side housing and a back housing 110B as a rear side housing while securing a back space, and a microphone unit 102 that is held by the back housing 110B and collects ambient sounds. Yes. In these figures, the sound output direction is the front and the opposite side is the back.

In addition, the inside of the cylindrical portion 110P is divided, and most of them are an acoustic path 130 that is an outlet for sound from the driver unit 101, and an independent ventilation duct 140 is provided in parallel with the acoustic path 130. Yes. Here, the sound path 130 is a transmission means (acoustic transmission path) for guiding the sound from the driver unit 101 into the ear canal.

On the other hand, the ventilation duct 140 is a conduction means for keeping the ventilation opening 140a provided outside the ear canal and at any position of the front housing 110F and the inside of the ear canal in a ventilation state. Here, the ventilation opening 140a is provided at any position near the front housing 110F of the cylindrical portion 110P, that is, outside the ear canal when the noise cancellation headphones 100 are used. The single ventilation opening 140a may be provided, but a plurality of ventilation openings 140a may be provided at any position of the front housing 110F with respect to one ventilation duct 140 as described in FIG. .

And the air permeability adjustment material 140F which adjusts air permeability between the ventilation opening 140a and the ear canal is provided on the ear canal side of the ventilation duct 140. Here, adjusting the air permeability means adjusting the air flow rate or the air flow resistance. The air permeability adjusting material 140F may be provided at any position of the air duct 140.

Further, on the output side of the sound path 130 and the ventilation duct 140, that is, on the vicinity of the tip of the cylindrical portion 110P, a tip filter 110TF for preventing foreign matter from being mixed is provided. In addition, an earpiece 120 made of silicon rubber or the like is attached around the vicinity of the tip of the cylindrical portion 110P so as to be fitted into the ear canal.

Also in the case of this second embodiment, in this case, although it is an insert type noise canceling headphone 100 in which the earpiece 120 and the ear canal are brought into close contact with each other, the outside of the ear canal and the inside of the ear canal are kept in a ventilation state by the ventilation duct 140.

For this reason, as shown in FIGS. 4 (1) and (3), even if the sealing condition between the earpiece 120 and the external auditory canal is good or low, the fluctuation of the frequency characteristic is the conventional (comparison). Example) Less than. Therefore, even if the sealing condition between the earpiece 120 and the ear canal changes, the noise canceling headphones 100 according to the present embodiment have a smaller noise canceling effect than the comparative example shown in FIG.

Furthermore, even when the ambient sound reaches the eardrum as a gap leakage sound through a portion where the sealing condition between the ear canal and the earpiece 120 is reduced, there is already ambient sound entering through the ventilation duct 140. Therefore, the level and phase of the ambient sound that reaches the eardrum do not change so much, and the noise canceling effect is not greatly reduced even when the sealing condition is good.

Also in this second embodiment, in any frequency region in the frequency characteristic diagrams shown in FIG. 3 and FIG. 4, there is a variation in the frequency characteristic diagram shown in FIG. 3 and FIG. It is possible to adjust whether the change occurs, how much the change in the change range occurs, in which frequency region the change is eliminated, and how much the change in the change range is eliminated.

[Other Embodiments]
In the first embodiment, the canal type noise cancellation headphones 100 in which the outer diameter of the front housing 110F is larger than the diameter of the earpiece 120 are shown as specific examples. In the second embodiment, the diameter of the earpiece 120 and the front housing 110F are Although the canal type noise canceling headphones 100 having substantially the same outer diameter are shown, even if the shape is other than this, the present invention is applied to provide a good noise canceling effect with little fluctuation in the insert type noise canceling headphones. Obtainable.

DESCRIPTION OF SYMBOLS 100 Noise cancellation headphones 101 Driver unit 102 Microphone unit

110F Front housing

110B Back housing

110P Tube part 120 Earpiece 130 Sound path 140 Ventilation duct 140a Ventilation opening part 140F Breathability adjustment material

Claims

A microphone unit that collects ambient sounds;
A driver unit that converts input electrical signals into sound;
A housing that houses the microphone unit and the driver unit;
A cylindrical portion provided in the housing so as to constitute a sound path for guiding the sound generated by the driver unit into the external auditory canal;
An earpiece that is made of a flexible material so as to be in contact with the inner surface of the ear canal and is arranged around the cylindrical portion;
An insert type noise canceling headphone with
A ventilation opening provided outside the ear canal and at any position of the housing;
A ventilation duct for communicating the ventilation opening with the ear canal;
Noise-canceling headphones characterized by comprising
The ventilation duct is configured as a part of the cylindrical portion, and has a space independent from the sound path as a ventilation path.
The noise-canceling headphone according to claim 1.
The ventilation duct is configured to be provided in parallel with the sound path in the cylindrical portion.
The noise-canceling headphone according to claim 1.
It is provided with a breathability adjusting material that adjusts breathability between the vent opening and the ear canal at any position of the vent duct.
The noise-canceling headphone according to claim 1.
A plurality of the ventilation openings are provided at any position of the housing with respect to one ventilation duct.
The noise-canceling headphone according to claim 1.