JPH0667679A - Active sound elimination system and sound eliminating device - Google Patents

Abstract

PURPOSE:To obtain the active sound elimination system which has a sufficient sound eliminating function even in an in-use state wherein there are plural sound sources and the position of the head always moves and the active sound eliminating device which is made simple and compact. CONSTITUTION:The active sound elimination system and sound eliminating device have an error microphone 2 and a speaker 3 for control and is equipped with a signal processing means 4 which control the control speaker with a reference signal regarding a sound entering the ears and performs control for minimizing the output of the error microphone 2 and further equipped with one or plural detection sensors 5 which are provided nearby a sound source 101 generating a sound to be eliminated corresponding to the sound source 101 and detects the sound, a mixer which mixes outputs at a specific level when there are plural sound sources, and transmitting means 6a and 4a which send out the output of the detection sensor 5 or the output of the mixer 6 as the reference signal to the signal processing means 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active muffling system and a muffling device which prevent external noises and the like to enable efficient work and clear communication.

[0002]

2. Description of the Related Art There is known an active sound deadening headphone having a function of canceling noise and the like coming from the outside.

FIG. 7 is an explanatory view for explaining the principle of a conventional active muffler headphone. As shown in the figure,
An error microphone 20 and a control speaker 30 are provided inside the pair of left and right headphones 10, and a detection microphone 40 is provided symmetrically outside thereof. The left and right error signal lines 20 for the left and right channels are connected to the signal processing device 50.
a, the control signal line 30a, and the reference signal line 40a.

Headphone 10 having such a configuration
When the detection microphone 40 detects a sound from the outside, the sound is sent to the signal processing device 5 through the reference signal line 40a.
When the signal processing device 50 receives this external sound signal, the signal processing device 50 generates a cancellation signal based on this signal and sends it to the control speaker 30 via the control signal line 30a to output from the error microphone 20. Is to be adjusted to the minimum.

[0005]

However, since the detection microphone 40 is installed just outside the headphone 10, the time when the detection microphone 40 detects an external sound and the external sound reaches the ear. Since there is not much time difference from the time, signal processing in this short time difference may not be in time, and it is effective for silencing synchronous sound and narrow band random sound, but silencing of wide band random sound that does not establish causality Had a problem that was difficult.

Further, in the structure of the conventional headphone with active silencer, since the detection position of the detection microphone 4 is constantly moved according to the movement of the head, a stable reference signal cannot be obtained and the silencing control is unstable. There was also a problem.

Further, when there are a plurality of external sound sources, a single sensor cannot detect the sounds from a plurality of sound sources equally, and the degree of association between the sound sensed by the ear and the reference signal is reduced and the sound is muted. There was also a problem that the effect could not be fully exerted.

Another problem is that the conventional headphone-type muffler is of a type that covers the entire ear and is troublesome when it is worn for a long time, and simplification thereof has been desired.

The present invention has been made to solve these problems, and has an active muffling system having a plurality of sound sources and a sufficient muffling function even in a use state in which the position of the head constantly moves, and a simple It is intended to provide a miniaturized active silencer.

[0010]

The active noise reduction system of the present invention has an error microphone and a control speaker, and controls the control speaker by a reference signal related to the sound coming into the ear to output the error microphone. In an active muffling system equipped with signal processing means for controlling to a minimum,

[0011] One or a plurality of detection sensors provided in the vicinity of a sound source that emits a sound to be muted and detecting the sound, and when there are a plurality of detection sensors, output of each of the detection sensors is set to a predetermined level. And a transmission means for transmitting the output of the detection sensor or the output of the mixer as a reference signal to the signal processing means to the outside. The transmission means is also characterized by using wireless.

Further, the silencer of the present invention has an error microphone and a control speaker, and controls the control speaker by the reference signal related to the sound coming into the ear to minimize the output of the error microphone. It is characterized by the fact that it is an earphone type configuration that incorporates an error microphone and a control speaker.

[0013]

By configuring the active silencing system in this way, the detection sensor is individually arranged for each machine and adjusted so as to have a high degree of association with the generated sound. A high level of noise reduction is possible. In addition, the portable headphones and signal processing device,
Since the detection sensor and its amplifier are not included, it is light and consumes less power. Furthermore, since the detection sensor is provided at a position away from the ear, signal processing is facilitated and wideband random sound can be silenced. In addition, when wireless is used, it can be applied to a plurality of sound sources, and the user can act freely. Since the muffler of the present invention is an earphone type, it is light and compact, and it is possible to work without the feeling of insertion.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram of the first embodiment.

Reference numeral 1 in the figure is a personal portable headphone composed of a pair of left and right sides of this embodiment. Inside the left and right sides of the headphone 1, an error microphone 2 is provided.
And a control speaker 3 are provided. The error microphone 2 and the control speaker 3 are integrated with the headphone 1 via the left and right L channel and R channel error signal lines 2a and control signal lines 3a. Is connected to the signal processing device 4.

Reference numeral 101 denotes a machine which serves as a vibration source or a sound source.
In the vicinity of the machine 101, a detection sensor 5 for detecting vibration or sound generated from the machine 101 and an amplifier 5a for amplifying the output of the detection sensor 5 to a predetermined level.
One set, or a plurality of sets if necessary,
In order to generate a reference signal having a high degree of association with the vibration or the generated sound of 01, it is provided at a position that is well investigated in advance.

When a plurality of detection sensors 5 are provided,
In order to make the reference signal representative of the machine 101, the outputs of the amplifiers 5a are mixed in the mixer 6, and the mixed output is used as the reference signal of the machine 101. This reference signal is output to a plurality of output jacks 6a provided near the machine 101.

When the headphone 1 is used near the machine 101, the plug 4b of the connection cable 4a for inputting the reference signal of the signal processing device 4 is inserted into the output jack 6a, and the reference signal is supplied to the signal processing device 4. It is configured so that a signal that minimizes the output of the error microphone 2 based on this reference signal is given to the control speaker 3 to perform active muffling. In this embodiment, the reference signal is commonly used for the L and R channels.

In this embodiment, as described above, the plurality of detection sensors 5 are properly arranged near the machine 101, which is the sound source, and these outputs are mixed at an appropriate level. A reference signal that is highly related to the incoming sound is obtained, and a high silencing effect is obtained by using this reference signal.

Further, the detection sensor 5 is a machine 10 which is a sound source.
Since it is installed in the vicinity of 1, there is a sufficient difference between the time when the reference signal is taken into the signal processing device 4 and the time when the sound of this machine 101 directly reaches the ear, and therefore the signal processing device 4 is silenced. It is possible to secure the processing time required to calculate the canceling signal for use and give it to the control speaker 3. This makes it possible to accurately mute random sounds.

FIG. 2 is a system configuration diagram of the second embodiment. This embodiment is an embodiment of a method of wirelessly transmitting a reference signal. As shown in the figure, a wireless receiver 7a is provided on the side of the signal processing device 4 carried by a person, and wireless transmission is performed on the output side of the mixer 6. A machine 7b is provided.

With this configuration, the reference signal representing the vibration or sound emitted by the machine 101 is transmitted to the wireless receivers 7a within the required electric field via the wireless transmitter 7b and can be used. Become.

Therefore, it is possible to save the labor of connecting the signal processing device 4 to the output of the mixer 6 through the connection cable 4a as in the first embodiment, and to secure the freedom of human behavior. FIG. 3 is a system configuration diagram of the third embodiment. In this embodiment, when there are a plurality of machines as sound sources, a radio transmitter 7b having the same frequency is provided corresponding to each of the machines 101 to 10n, and a reference signal of each machine is supplied from each radio transmitter 7b to a required electric field. This is an embodiment of transmitting to all the wireless receivers 7a in the inside.

The radio receiver 7a connected to the signal processing device 4 carried by a person mixes and receives a plurality of reference signals sent from each machine, and controls the signals based on the mixed received signals. Since the control signal to be sent to the speaker 3 is generated in a form including each reference signal and the muffling control is performed, this embodiment is very effective when sounds are heard from the machines 101 to 10n of a plurality of sound sources. There is.

The magnitude of the sound emitted from the machines 101 to 10n in relation to the ear is related to the distance to the sound source, but the radio field intensity is also related to the distance, and the received signal is large when the sound is emitted near the transmitting position. Become. For this reason, a high degree of association is always maintained between the sound directly coming from the machines 101 to 10n and the received signal from the wireless receiver 7a. In these embodiments, a better reference signal can be obtained by providing a filter between the detection sensor 5 and the mixer 6 to correct the sound quality. In the case of using wireless, if the frequency is changed for each machine and the frequency is selected at the time of reception, it is also possible to select the machine whose sound is to be silenced.

Further, if the signal processing device 4 is provided with a separate receiving circuit for communication and the received contents received by this receiving circuit are overlapped with the control signal sent to the control speaker 3, the received contents are heard without being muted. be able to. The embodiment shown in FIGS. 4 to 6 is an embodiment in which the headphone 1 is downsized to an earphone type. FIG. 4 shows a first earphone type embodiment in which the error microphone 2 and the control speaker 3 are integrated.

In the figure, reference numeral 8 denotes an earphone of this embodiment. When the earphone 8 is inserted into the ear 201, the error microphone 2 is provided at an internal position facing the eardrum 203 via the ear canal 202, and thereafter A control speaker 3 is provided on the external side, and each signal line and error signal line 2a is provided.
The control signal line 3a is connected to the signal processing device 4 (not shown).

With this configuration, the error microphone 2 detects a sound wave in which the sound coming into the ear canal 202 from the outside and the signal sound sent from the control speaker 3 are superposed and sent to the signal processing device 4 for signal processing. The device 4 performs a silencing operation to control the signal sent to the control speaker 3 so that the output of the error microphone 2 thus sent is minimized.

FIG. 5 shows a second earphone type embodiment. In this embodiment, the error microphone 2 is provided outside the control speaker 3, the sound of the ear canal 202 is guided to the error microphone 2 by the waveguide 9 penetrating the control speaker 3, and the error microphone 2 is fed to the flow microphone. To act as.

FIG. 6 shows a third earphone type embodiment. In this embodiment, as in the previous embodiment, the error microphone 2 is provided outside the control speaker 3, and the ear canal 2 is provided.
In this embodiment, the sound 02 is guided to the error microphone 2 by the waveguide 9 that bypasses the control speaker 3.

In these embodiments, the output of the error microphone 2 is controlled by the characteristics of the control speaker 3 and the ear canal 202.
By correcting using the transfer characteristic of, it is possible to improve the sound deadening effect. The present invention is not limited to the above-mentioned embodiments, and can be modified and carried out within the scope of the invention.

[0032]

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

(1) Since the detection sensor is adjusted and arranged individually for each machine and so as to have a high degree of association with the generated sound, stable high silencing can be achieved by the reference signal obtained from this detection sensor. (2) Since the headphone and the signal processing device to be carried do not include a detection sensor, its amplifier, etc., it is light and consumes less power. (3) A large number of detection sensors can be provided on the machine side in order to obtain a reference signal that is highly related to the generated sound, without imposing a burden on a person. (4) Since the detection sensor is installed at a position far from the ear,
Signal processing becomes easy and wideband random sound can be silenced. (5) When using wireless, it can be applied to multiple sound sources, and the user can act freely. (6) When the head hane is an earphone type, it is light and small, so it is possible to work without having the feeling of insertion.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a muffling system according to a first embodiment of the present invention.

FIG. 2 is a system configuration diagram of a second embodiment using wireless.

FIG. 3 is a system configuration diagram of a third embodiment in which wireless is used for a plurality of machines.

FIG. 4 is a sectional structural view showing the configuration of the earphone type first embodiment.

FIG. 5 is a sectional structural view showing a configuration of an earphone type second embodiment.

FIG. 6 is a sectional structural view showing the configuration of a third embodiment of an earphone type.

FIG. 7 is a configuration diagram of a conventional active sound deadening headset.

[Explanation of symbols]

1 ... Headphone, 2 ... Error microphone, 2a ... Error signal line, 3 ... Control speaker, 3a ... Control signal line, 4
... signal processing device, 4a ... connection cable, 4b ... plug 5 ... detection sensor, 5a ... amplifier, 6 ... mixer, 6a ...
Output jack 7a ... Wireless receiver, 7b ... Wireless transmitter, 8
... Earphones, 9 ... Waveguides, 101, 10n ... Machines, 2
01 ... ear, 202 ... external auditory meatus, 203 ... eardrum.

Claims (4)

[Claims] 1. A signal processing means having an error microphone and a control speaker, wherein the control speaker is controlled by a reference signal relating to a sound coming into the ear to control the output of the error microphone to a minimum. In the provided active noise reduction system, one or more detection sensors that are provided near the sound source that emits the sound that you want to mute and detect the sound, and if there are multiple detection sensors, output of each detection sensor A mixer for mixing at a predetermined level, and a transmission means for transmitting the output of the detection sensor or the output of the mixer as a reference signal to the signal processing means to the outside, an active muffling system, 2. The active muffling system according to claim 1, wherein the transmitting means is a wireless transceiver. 3. A silencer having an error microphone and a control speaker, wherein the control speaker is controlled by a reference signal relating to a sound coming into the ear to control the output of the error microphone to a minimum. Yes, an earphone-type silencer with a built-in error microphone and control speaker. 4. The silencer according to claim 3, further comprising a wave guide means for guiding the sound in the external auditory meatus when it is attached to the ear to the error microphone.