JPH059038B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a soundproofing device used for work in high noise environments such as factories and airports.

``Prior Art'' In general, prolonged exposure to environments with high noise levels of 90 dB or more can lead to hearing loss and other disorders.
When working in such an environment, some kind of soundproofing measures are necessary.

BACKGROUND ART Shion-shaped earmuffs called earplugs or earmuffs have been used for a long time. The advantage of this method is that the structure does not include electrical circuits, so it can be provided at low cost, and it also has a great soundproofing effect.

However, since these systems emit a muffled sound across the entire range of sounds, they have drawbacks such as the inability to hear human speech and the necessary operating and modulated sounds of machinery.

One way to solve these drawbacks is to use a bandpass filter. (Unexamined Japanese Patent Publication 1973)
(No. 135503, No. 57-75100) These devices first input ambient sound through a microphone, pass it through a bandpass filter, and then output it to earphones. Ambient sounds are physically dampened by the earphones, and only the necessary frequency bands, such as voice, are output from the earphones, making it possible to have a conversation even in high-noise environments. However, in reality, there are generally many other sounds that are needed in addition to voice.

For example, in factories and the like, it is not uncommon to hear the proximity of dangerous objects or abnormal noises from machinery and take necessary measures. Desirably, only particularly high-level sounds and sounds that cause discomfort should be removed, and the passband should be as wide as possible. And these particularly high-level sounds and sound bands that cause discomfort are
often specific to the location.

Therefore, if only the sound in that band is to be removed, the frequency characteristics of the filter must be widened and adjusted to a band specific to the site. Once a conventional filter circuit has been assembled, if the circuit constants are to be changed, the circuit must be reassembled, which is time-consuming and not easy.

Furthermore, the method of preparing several frequency adjustment elements in advance and adjusting them using switches or the like or resistors requires a complicated circuit, a large device, and is inconvenient to carry.

"Problems to be Solved by the Invention" The present invention provides a small and portable soundproofing device whose circuit constants can be easily adjusted depending on the characteristics of the noise source.

"Means for Solving the Problem" The present invention provides the following advantages when a bandpass filter having a certain frequency bandwidth is inserted into a signal transmission/amplification circuit between a microphone and an electroacoustic transducer such as an earphone. It is provided with a socket into which one or more adjusting elements such as coils and capacitors for adjusting the frequency pass band can be inserted and pulled out.

"Function" According to the present invention, when a necessary frequency adjustment element is placed in a circuit, the connection can be easily made by hand without using a soldering iron or the like. By preparing the required number of adjustment elements with different frequency pass constants, the frequency pass band of the band pass filter can be adjusted.
It can be freely adjusted according to the situation at each site.

The present invention will be explained in more detail with reference to Examples below.

Embodiment 1 FIG. 1 is a block wiring diagram showing the configuration of a conventional soundproofing device using a bandpass filter.

As is clear from FIG. 1, it consists of a microphone 1, amplifiers 2 and 5, a bandpass filter, a volumetric volume, and a voice conversion speaker 6. A signal sound inputted from a microphone is converted into an electric signal, passes through an amplifier 2, a bandpass filter 3, a volumetric volume 4, and an amplifier 5, and is supplied to a speaker 6.

For example, an LC circuit as shown in FIG. 2 is used as the bandpass filter. Since high-frequency sounds are gradually removed by L and low-frequency sounds are removed by C, only a specific frequency band passes through. The upper and lower limits of the frequency band are adjusted by the values of L and C. The optimal L-C after adjustment is combined and fixed on the board by soldering.

Furthermore, if a plurality of LCs are fixedly wired on the board in advance and the circuits can be switched using a rotary switch or the like, the pass frequency band can be adjusted by operating the switch.

The general structure of the soundproofing device of the present invention can be used as is in conventional soundproofing devices.

The present invention is significantly different from conventional soundproofing devices in the mounting method of the bandpass filter. That is, as shown in FIG. 3, a socket 7 into which a frequency adjustment element is inserted is provided.

A coil, a capacitor, a resistor, a transistor, an IC, or a circuit including these can be used as the frequency adjustment element. In this embodiment, a coil L and a capacitor C are used as frequency adjustment elements.

FIG. 4 shows the configuration of the bandpass filter portion of the soundproofing device of the present invention. Here 8,
Numerals 9, 10, and 11 are frequency adjustment elements, which can be freely inserted into the socket 7 and replaced.

By appropriately changing the constants of L1, L2, C1, and C2, a desired frequency band can be arbitrarily cut.

Embodiment 2 FIG. 5 is an example of a bandpass filter portion of a soundproofing device according to this embodiment of the present invention.

Here, C1 removes the low frequency band, and C2 removes the high frequency band by bypassing. The use of only C simplifies the circuit and reduces the size, which is very convenient. However, with this method, the frequency cut curve is gentle in both the low and high ranges.

Furthermore, if necessary, the frequency band can be easily adjusted by using duplicate socket connections in series or parallel.

Further, in using the present invention, the following forms are possible.

(1) Earphone type The circuit board including the socket of this device, microphone, battery, etc. are housed in a small case, and binaural earphones are used as electroacoustic transducers. The main case is used by putting it in the pocket of a jacket or shirt.

(2) Headphone type This is a method that uses a sound-type headphone as an electroacoustic transducer, but it is also possible to use a headphone instead of the earphones in (1), but it is also possible to use a headphone with a circuit board that includes a socket inside the headphone container. , microphone, batteries, etc.

This type is very easy to use as it does not require external cords for earphones or headphones.

(3) Helmet type This is a method of storing everything other than earphones or headphone inside a helmet, and this method is very important in places where helmets are required to be used.

``Effects'' The present invention is very efficient because the frequency band can be easily adjusted on site by using a socket for an adjustment element that determines the frequency band. Furthermore, since there is no need to perform wiring or soldering each time an adjustment element is replaced, the soundproofing system specific to the site can be easily and economically maintained. However, it also causes less fatigue and other burdens than conventional products.

In addition, it is possible to eliminate unnecessary sounds according to the work environment, so you can hear not only human conversations but also machine operating sounds, which can greatly improve workplace safety. .

Furthermore, if two microphones are installed separately to create a stereo system, the sense of direction and distance of the sound will be provided, further improving safety.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the soundproofing device. FIG. 2 is a wiring diagram of a bandpass filter. FIG. 3 is a block diagram of the soundproofing device of the present invention. 4 and 5 are wiring diagrams showing an example of a bandpass filter of a soundproofing device. 1: Microphone, 2, 5: Amplifier, 3: Bandpass filter, 4: Volume, 6: Speaker (earphone), 7: Socket for frequency band adjustment element, 8, 9, 10, 11: Frequency band adjustment element.

Claims (1)

[Claims] 1. (a) Microphone for collecting ambient sound; (b)
an amplifier for amplifying a signal from a microphone; (c) a bandpass filter having a fixed frequency passband; (d) a bandpass filter consisting of an adjustment element for adjusting the frequency passband; and one or more adjustments. A socket into which the element can be inserted and pulled out, (e) an amplification adjuster that adjusts the level of the output signal, (f) an electroacoustic transducer that reproduces the adjusted output, and the main parts (a) to ( f) A soundproofing device characterized by comprising: 2. The soundproofing device according to claim 1, wherein the socket has a structure in which a plurality of frequency adjustment elements can be inserted in parallel or in series.