JPH02252399A - Audible signal listening device - Google Patents

Abstract

PURPOSE:To reduce a noise from an external part, and to make only a desired audible signal easy to listen by making a characteristic into the characteristic which corresponds to the acoustic frequency characteristic of the external noise before it reaches an auditory meatus and in addition, inverts its phase. CONSTITUTION:A control circuit 3 realizes the frequency characteristic and a phase characteristic which correspond to the acoustic frequency characteristic of the external noise before it reaches an ear and in addition, inverts its phase as a whole circuit from a microphone 2 to a pronouncing means 6. An electric audible signal amplified by an amplifier 8 is inputted separately to an adder 5 through a terminal 7. The adder 5 adds electrically an output signal from the circuit 3 and the audible signal, and supplies it to the means 6. The means 6 electroacoustic-converts the output signal from the adder 5, and pronounces it as an acoustic signal. The pronounced acoustic signal is added acoustically with the acoustic signal from an acoustic characteristic block 10 by an adding means 9, and is supplied to a sound output terminal 11 corresponding to the auditory meatus.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to, for example, a portable headphone player.

The present invention is suitable for use in pilot communication devices for airplanes, helicopters, etc., telephone receivers, etc., and particularly relates to an audible signal listening device that reduces external noise and makes it easy to hear only desired audible signals.

[Summary of the invention]

The audible signal listening device according to the present invention is provided with an acoustic-to-electrical conversion means such as a microphone that picks up external noise near the ear when worn, and an electric-to-acoustic conversion means such as a headphone unit that is a sounding means, and the microphone The characteristics between the external noise and the headphone unit are set to correspond to the acoustic frequency characteristics of the external noise reaching the auditory canal and to invert the phase, such as the reproduction signal from a portable headphone player, etc. By adding the electrical audible frequency signal (audible signal) and simultaneously emitting sound from the headphone unit, external noise reaching the ear canal from the outside is reduced, and only the desired audible signal such as the above playback signal can be clearly heard. It is something that you can listen to.

[Conventional technology]

Conventionally, when listening to a playback signal from a portable headphone player or the like using a headphone device in a place with high external noise,
When the external noise is high, it is difficult to hear the reproduced signal, so the level of the acoustic reproduced signal is increased by raising the polynium sound.

Further, when a pilot of a helicopter or an airplane communicates with a control tower or the like, the inside of the cockpit is exposed to high noise such as engine noise, and it may be difficult to hear the contents of the communication. For this reason, pilots communicate by wearing so-called earmuff-type headphone devices that press the headphone cup against the side of the head to prevent external noise from entering through the gap between the side of the head and the headphone cup. Ta.

Furthermore, when using a public telephone or the like with high external noise, the user and the other party had to talk loudly to each other.

By the way, as a device for reducing external noise that interferes with hearing signals in the audible frequency band (audible signals) such as music and voices, for example, Japanese Patent Application Laid-Open No. 62-0279
An active type headphone device as disclosed in the headphone disclosed in Japanese Patent No. 8 is also known.

This active type headphone device converts external noise into an electrical signal using a microphone unit and returns it in the opposite phase, thereby reducing noise near the headphone unit, thereby allowing audible signals such as voice signals to be transmitted. is made easier to hear.

[Problem to be solved by the invention]

However, if you listen to the sound reproduction signal by raising the volume of the portable headphone player above the external noise,
The sound reproduction signal leaks to the surroundings, causing a nuisance and causing hearing problems.

The above-mentioned earmuff-type headphone device used by the pilot when communicating must have the headphone cup pressed firmly against the side of the head in order to reduce external noise that enters through the gap between the headphone cup and the side of the head. Feeling of pressure in the head,
Furthermore, the headphone device itself is large and heavy, making it difficult to withstand long-term use.

Furthermore, in the case of the above-mentioned telephone, it is desired to develop a telephone that allows conversation without being affected by surrounding noise.

Furthermore, in the case of the above-mentioned active type headphone device, operational instability due to the feedback loop remains, and there is a possibility that adverse effects such as oscillation may occur.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an audible signal listening device that can reduce external noise reaching the auditory canal from the outside and make it possible to clearly hear desired audible signals. do.

In order to solve the above-mentioned problems, the audible signal listening device according to the present invention has a microphone 2 which is provided near the ear when worn and is an acoustic-electric conversion means for collecting external noise.
, a characteristic transmitting means 15 (control circuit 3 and amplifier circuit 4) having a predetermined phase characteristic 1 frequency characteristic and to which an output signal from the microphone 2, which is the acoustic-electric converting means, is supplied; and this characteristic transmitting means 15. an adder 5 for adding an electrical signal from the adder 5 and an electrical audible signal from the outside, and an electro-acoustic conversion means provided near the ear for converting the signal from the adder 5 into an acoustic signal. The microphone 2, which is the acoustic-to-electrical conversion means,
It is characterized in that the characteristics up to the sound generating means 6, which is the acoustic converting means, correspond to the acoustic frequency characteristics of the external noise before it reaches the auditory canal, and the characteristics are such that the phase is inverted.

[For production]

[Means for Solving the Problems] The audible signal listening device according to the present invention makes the characteristics between the microphone 2 and the sounding means 6 correspond to the acoustic frequency characteristics during the time when external noise reaches the ear canal. In addition, since it has a characteristic of inverting the phase, the external noise is collected by the microphone 2, added to an audible signal (for example, an audio playback signal from a portable headphone player), and the sound is generated by the sound generating means 6. As a result, external noise reaching the auditory canal from the outside can be reduced, and the audible signal (audio signal, etc.) can be heard clearly.

〔Example〕

Embodiments of the audible signal listening device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram showing the basic configuration of an audible signal listening device according to the present invention.

In FIG. 1, acoustic external noise is supplied to a microphone 2, which is an acoustic-to-electrical converting means, through an audio input end 1, thereby converting the external noise into an electrical signal. The output signal from the microphone 2 is supplied to a control circuit 3 of a characteristic transmitting means 15 consisting of a control circuit 3 and an amplifier circuit 4. This control circuit 3, as a whole circuit from the microphone 2 to the sound generating means 6, realizes frequency and phase characteristics that correspond to the acoustic frequency characteristics and invert the phase of external noise while it reaches the ear. It is for the purpose of The output signal from the control circuit 3 is amplified by the amplifier circuit 4 and supplied to the adder 5. Separately, an external electrical audible signal amplified by an amplifier circuit 8 is input to the adder 5 via an input terminal 7. This audible signal refers to an audio signal or music signal in the audible frequency band that you are trying to listen to, such as the voice of the other party when a pilot of an airplane communicates with the ground, or the voice of the other party on a telephone call. etc., or an audio playback signal from a headphone player. The adder 5 adds (electrically adds) the amplified output signal from the control circuit 3 and the audible signal and supplies the result to the sounding means 6. The output signals from the amplifier circuit 4 and the amplifier circuit 8 are subjected to electro-acoustic conversion and generated as an acoustic signal. This emitted acoustic signal is added (acoustically added) to the acoustic signal from the acoustic characteristic block 10 in the adding means 9, and is supplied to the acoustic output end 11 corresponding to the auditory canal. Here, the acoustic characteristic block 10 shows the acoustic characteristics between the acoustic input end 1 and the acoustic output end 11. That is, before the external noise reaches the auditory canal, the frequency spectrum changes due to, for example, the shape of the ear or head, or because it passes through the sounding means 6. This acoustic frequency characteristic is expressed as an acoustic circuit block.

Next, as a first embodiment of the present invention, a case will be described in which the audible signal supplied to the input terminal 7 is a reproduced signal from a portable headphone player.

FIG. 2 is an external view showing the usage state of a specific example in which the audible signal listening device of this embodiment is applied to an inner-type headphone device for listening to reproduced signals of a portable headphone player, and FIG. It is a sectional view taken along the line A-A. Note that this second
In the figure and FIG. 3, the same parts as in FIG. 1 are given the same reference numerals. The sound generating means 6 shown in FIG. 1 in case 2 corresponds to the headphone unit 25.

In FIGS. 2 and 3, the inner headphone device includes a headphone unit 2 in which a sounding body 25b is built-in.
By attaching the microphone 2 to the housing 25a of 5, when the headphone device is attached to the ear 21, the sounding body 2
5b and the microphone 2 are arranged near the ear 21. Then, the sounding body 25b is connected to the mesh 2.
5c and connected to the sounding body 25b.
5d and the lead wire 2a connected to the microphone 2.
is pulled out from the lead pullout section 25e.

When such an inner headphone device is worn on the ear 21, external noise is collected by the microphone 2 installed near the ear canal 22, and is converted into an electrical noise signal through acoustic-to-electrical conversion. Characteristic transmission means 1 shown in Figure 1
5 is input to the control circuit 3.

The control circuit 3 controls the output signal from the microphone 2 based on the frequency characteristics and phase characteristics as described above. The output signal from this control circuit 3 is amplified by an amplifier circuit 4 having a predetermined gain and is supplied to an adder 5 as a first electrical signal. The adder 5 is separately supplied with a second electrical signal which is a playback signal from a portable headphone player, and the adder 5 adds the first electrical signal and the second electrical signal (electrically The headphone unit 25, which is the sounding means 6 of the electro-acoustic conversion means, converts the signal into an acoustic signal and sounds it.

This acoustic signal is added (acoustically added) to the external noise via the acoustic characteristic block 10 in the auditory canal 22.
At this time, the acoustic component corresponding to the first electrical signal of the acoustic signal emitted from the headphone unit 25 is combined with external noise reaching the ear canal 22 from the outside via the acoustic characteristic block 10. Since they have the same frequency spectrum and opposite phases, they serve to cancel out the external noise. Therefore, the second electrical signal (audible signal)
Only the acoustic components corresponding to the sound can be clearly heard.

That is, the sound pressure at the acoustic input terminal 1 is N, the transfer function of the microphone 2 is M, the transfer function of the control circuit 3 is β, and the transfer function of the amplifier circuit 4 is A1. The transfer function of the headphone unit 25 which is the sound generating means 6 is H, the input signal (reproduction signal) of the input terminal 7 is S, the transfer function of the amplifier circuit 8 is Az, the transfer function of the acoustic characteristic circuit 10 is F, and the transfer function of the acoustic output terminal 11 is When the sound pressure is expressed as P, the sound pressure P is expressed as: P=A, H3+(F+A, HMβ)N. In addition, each transfer function M, β, A, ,A, ,H
, F are expressed in the frequency domain. In order to make the sound pressure P of the auditory canal 22 only an audio signal, the sound pressure N of external noise is
It is sufficient to set the coefficient to 0. Therefore, the transfer function β of the control circuit 3 is F+A, HMβ=0, . The characteristic should be β=-F/A, 8M.

Here, when the microphone 2 is provided near the auditory canal 22 as in the specific example shown in FIGS. 2 and 3, the frequency characteristic F of the acoustic characteristic block 10 shown in FIG. Therefore, the frequency characteristics M of the microphone 2 are approximately equal (F!=iM) as shown in FIG. 5, and in this case, βζ-1/A,H. That is, since the ratio M/F of these frequency characteristics M and F is approximately flat up to about 1.5 KHz as shown in FIG.
As for (characteristic β), external noise reaching the auditory canal 22 from the outside can be canceled by simply reversing the phase as described above or by simply correcting the transmission characteristic H of the headphone unit 6. Therefore, only the acoustic audible signal (reproduction signal) can be clearly heard with a simple configuration.

Note that the adder 5 may be provided before the amplifier circuit 4, as shown in the adder 12.

As is clear from the above explanation, the microphone 2, which is an acoustic-to-electrical conversion means, is installed near the auditory canal of the headphone unit 25, which is the sounding means 6, and collects external noise. A signal with the same frequency spectrum and opposite phase as when reaching the road is electrically generated, added to the playback signal from a portable headphone player, etc., and simultaneously produced by a headphone unit, etc., which is an electro-acoustic conversion means. By doing so, you can reduce external noise, and even in places with high external noise, you can clearly hear only the audible signal (acoustic playback signal) from the portable headphone player without raising the volume more than necessary. can.

Next, as a second embodiment of the present invention, a case will be described in which the reproduced signal inputted from the input terminal 7 is a communication signal of a pilot of an airplane or a helicopter.

FIG. 7 is a cross-sectional view showing a specific example in which the audible signal listening device of this embodiment is applied to an ear-muff type headphone device, and is applied to a so-called headset, a communication device used by pilots of airplanes and helicopters. be. Note that in FIG. 7, the same parts as in FIG. 1 are given the same reference numerals. In this case, the sound generating means 6 shown in FIG. 1 corresponds to the headphone unit 70.

In this figure 7, the Herad set is headphone cup 7.
A microphone 2 that picks up external noise and a headphone unit 70 that outputs signals received from, for example, a control tower are built in. An earbutt 72 is provided at the contact portion of the headphone cup 71 with the side of the head, and a bar 74 is attached to the outside of the headphone cup 71, and a transmitting microphone 73 is attached to the tip of the bar 74. ing.

The schematic circuit configuration in this case is also the same as that shown in FIG. That is, in FIGS. 1 and 7, a microphone 2 picks up external noise such as engine noise through an acoustic input terminal 1, converts it into an electrical signal, and a control circuit 3 receives external noise such as engine noise. A signal having the same frequency spectrum and opposite phase as when the noise reaches the auditory canal is electrically generated, amplified by an amplifier circuit 4, and supplied to an adder 5 as a first electrical signal. A communication signal (audio signal) from, for example, a control tower, which is amplified by an amplifier circuit 8 via an input terminal 7, is supplied to the adder 5 as a second electric signal. The first electrical signal and the second electrical signal are added and supplied to the headphone unit 70. The headphone unit 70 performs electro-acoustic conversion on the second electric signal, which is a communication signal from the control tower, and generates sound. The external noise is canceled by electro-acoustic conversion of the first electrical signal, which is controlled to have the same frequency spectrum and opposite phase as the frequency spectrum of the engine noise (such as the engine noise mentioned above), and is emitted as an acoustic signal. , only audible signals, which are communication signals, can be clearly heard.

Note that in FIG. 7, the same parts as in FIGS. 1, 2, and 3 are designated by the same reference numerals, and their explanations are omitted.

In the case of a headset, there is an ear pad 72.
The frequency characteristic F of the above-mentioned acoustic characteristic block 10 is a low frequency characteristic (approximately I
K) tz or less), there is almost no effect of the ear pad 72, and by installing the microphone 2 in a position close to the ear canal 22, the frequency characteristics of the F and M become approximately equal as described above, and the control B circuit The external noise can be canceled by simply reversing the phase of the external noise collected in step 3 or by simply correcting the transfer characteristic H of the headphone unit 6.

In addition, the side part of the head is covered with a headphone cup (ear pad 71, etc.).
Since there is no need to hold it in place or use lateral pressure to block out external noise, it can withstand long-term use without feeling uncomfortable.

Next, as a third embodiment of the present invention, a case will be described in which the reproduced signal inputted from the input terminal 7 is an incoming signal from the other party on the telephone.

FIG. 8 is a partially cutaway perspective view showing a specific example in which the audible signal listening device of this embodiment is applied to a telephone handset, a so-called handset. Note that in FIG. 8, the same parts as in FIG. 1 are given the same reference numerals. In this case, the sound generating means 6 shown in FIG. 1 corresponds to the speaker unit 84.

In FIG. 8, the handset is provided with an earpiece 82 and a mouthpiece 83 at both ends of a grip 81. As shown in FIG. The earpiece 82 has a built-in speaker unit 84 that simultaneously produces an acoustic signal with the same frequency spectrum and opposite phase as the received voice signal and external noise, which will be explained later. A microphone 2 for picking up external noise is built-in. Further, the mouthpiece 83 has a built-in microphone 85 for transmitting speech.

The schematic circuit configuration in this case is also the same as that in FIG. That is, in FIGS. 1 and 8, a microphone 2 picks up external noise, which is environmental noise such as the sound of a car engine, through an audio input end 1, converts it into an electrical signal, and sends it to the control circuit. 3, electrically generates a signal having the same frequency spectrum and opposite phase as when the external noise reaches the auditory canal, amplifies it in the amplifier circuit 4, and sends it to the adder 5 as a first electrical signal. supply The adder 5 is supplied with a received signal from the other party as a second electric signal, which is amplified by an amplifier circuit 8 via an input terminal 7.
The adder 5 adds the first electrical signal and the second electrical signal and supplies the result to a speaker unit 82, which is the sounding means 6 shown in FIG.

The speaker unit 82 performs electro-acoustic conversion on the second electric signal, which is the reception signal, and generates sound. By electro-acoustic converting the first electrical signal, which is controlled to have an opposite phase in the same frequency spectrum, and emitting it as an acoustic signal, the external noise is canceled and only the audible signal, which is the received signal, becomes clear. can be heard.

In this case as well, by installing the microphone 2 in a position close to the ear canal 22, the frequency characteristics of the F and M become approximately equal as described above, and the external noise is reduced to the extent that the transmission characteristic H of the speaker unit 84 is easily corrected. can be canceled out.

Note that in FIG. 8, the same parts as in FIGS. 1, 2, and 3 are designated by the same reference numerals, and their explanations are omitted.

In this way, by applying the audible signal listening device according to the present invention to a telephone handset, it is possible to have a conversation without being affected by external noise.

Note that the audible signal listening device according to the present invention is not limited to the above-described embodiments, and can also be applied to, for example, transceivers used in high noise environments such as construction sites, helmets with headphones, etc. It can be easily achieved.

〔Effect of the invention〕

The audible signal listening device according to the present invention is provided with an acoustic-electrical conversion means and an electro-acoustic conversion means near the ear when worn, and collects external noise with the acoustic-electrical conversion means and enters the auditory canal from the outside. The first signal controlled in this way is controlled to be a signal with the same frequency spectrum but the opposite phase as the arriving external noise, and the electrical audible signal from the outside, such as a portable headphone player, is added. At the same time, by emitting sound from the electro-acoustic conversion means which is the sounding means, the acoustic signal component corresponding to the first signal in the emitted acoustic signal reduces external noise reaching the auditory canal from the outside. Therefore, only the audible signal can be clearly heard.

[Brief Description of the Drawings] Fig. 1 is a block diagram showing the basic configuration of the audible signal listening device according to the present invention, and Fig. 2 shows the use of the audible signal listening device of the present invention when applied to an inner-type headphone device. Figure 3 is a cross-sectional view taken along the line A-A in Figure 2, Figure 4 is the output frequency characteristic diagram of the acoustic characteristic block, Figure 5 is the output frequency characteristic diagram of the microphone, and Figure 6 is the microphone output frequency characteristic diagram. FIG. 7 is an M/F frequency characteristic diagram showing the ratio of the frequency characteristic M of the acoustic characteristic block to the frequency characteristic F of the acoustic characteristic block. FIG. 8 is a partially cutaway perspective view showing the state in which the audible signal listening device of the present invention is applied to a telephone handset. ■...Acoustic input end 2...Microphone 3...Control circuit 4.8...Amplification circuit 5.12...Adder 6 ..... Sound generation means 7 ..... Input terminal 9 ..... Adding means 10 ..... Acoustic characteristic block 11 ..... Acoustic Output end

Claims (1)

[Scope of Claims] Acoustic-to-electrical conversion means that is provided near the ear when worn and picks up external noise; and an output signal from the acoustic-to-electrical conversion means having predetermined phase characteristics and frequency characteristics. the supplied characteristic transmission means; an adder for adding the electrical signal from the transmission characteristic means and an external electrical audible signal; Electricity converted into a signal
an acoustic converting means, the characteristic between the acoustic-electrical converting means and the electric-acoustic converting means corresponds to the acoustic frequency characteristic during the external noise reaching the auditory canal, and the phase is reversed. An audible signal listening device characterized by having the following characteristics.