JPH03273798A - Electronic silencing system - Google Patents

Abstract

PURPOSE:To freely set a sound environment by changing the silencing effect of an electronic silencing system and freely changing the level and frequency characteristic of noise by adding a certain function to a controller so as to freely control the generating volume and frequency characteristic of an additional sound. CONSTITUTION:Based on information from a sensor microphone 2 and an error microphone 2A, a controller 3 generates the additional sound, which phase is reverse to that of noise 6 propagated in a duct, from a loudspeaker 4 for acoustic wave interference and silences the noise. The silenced and level-reduced noise 6 propagated in the duct is propagated through an air blowing out port 5 installed in a living room 7 into the living room. In such a case, the controller 3 is equipped with the function to freely change the generating volume and frequency characteristic of the additional sound which phase is reverse to that of the noise. Thus, the silencing characteristic of the electronic silencing system 1 is controlled and low air conditioning noise 8 or air conditioning noise 9 including masking noise can freely be set.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an electronic sound silencing system that generates additional sound with a phase opposite to that of air conditioning and sound absorption in an air conditioning duct leading to a living room to eliminate sound wave interference. In particular, the present invention relates to an electronic silencing system that can freely control the silencing effect by controlling the volume and frequency characteristics of additional sound.

Note that the term "living room" is used to include building spaces that people enter, such as factory spaces and offices.

[Conventional technology]

Conventionally, a countermeasure against air conditioning duct noise 6 has been to install a sound-absorbing duct 12 lined with sound-absorbing material in the middle of the air-conditioning duct that connects the air conditioner to the living room 7 and air-conditions the living room 7, as shown in FIG.
This is done by installing a number of passive silencers, including sound-absorbing silencers such as silencing elbows and sound-absorbing silencers, and expansion silencers that utilize the reflection of sound waves.

On the other hand, the comfort of the sound environment is greatly influenced by psychological factors, so the lower the noise level in living room 7, the better it is not necessarily, but the sound environment should be set to suit the usage condition and purpose. Should. For example, the quiet living room 7 is suitable for meetings and the like because voices can be transmitted clearly, but when used as an office or the like, it may be too quiet and difficult to use. This is because living room 7 is quiet, so external noise such as noise from the next room and noise from OA equipment can be clearly heard by the people in the living room, so the noise is not bothersome and has a psychological impact. This is because work efficiency decreases. On the other hand, with conventional passive silencers, the silencing effect cannot be varied and the sound environment cannot be freely set.

Therefore, in order to obtain a comfortable sound environment, a speaker 11 is installed in the quiet living room 7 to generate secondary sounds such as BGM, bio music, masking sound, etc. depending on the purpose of the living room. Countermeasures are being taken, such as psychologically masking external noise and creating a sound environment that matches the usage conditions of the room. However, this method required extensive equipment and was difficult to adjust.

In addition, in recent years, electronic silencing systems have been put into practical use that generate additional sound that is in the opposite phase of the noise and muffle the sound through sonic interference.Although these systems have been shown to be highly effective in reducing noise in air conditioning ducts, The purpose was only to maximize the silencing effect, and there was no idea of freely setting the sound environment in the living room.

[Problems to be Solved by the Invention] The purpose of the present invention is to eliminate the drawbacks of the above-mentioned prior art, and to
To provide an electronic silencing system that can freely change the sound level and frequency characteristics and freely set the sound environment.

[Failure to solve the problem]

A function is added to the controller to freely control the generated volume and frequency characteristics of the additional sound for sonic interference of the electronic silencing system, and as a result, the silencing effect of the electronic silencing system is changed, creating a new sound environment in spaces such as living rooms. It is characterized in that it can be controlled without placing speakers, audio devices, etc.

〔Example〕

FIG. 1 shows an embodiment of the present invention. The living room 7 and the air conditioner are connected by an air conditioning duct, and an electronic silencing system 1 is installed in the air conditioning duct to prevent duct noise 6. Electronic silencing system 1 includes sensor microphone 2
, an error microphone 2A, a controller 3, and an additional sound speaker 4. Based on the information from the sensor microphone 2 and the error microphone 2A, the controller 3 causes the sound wave interference speaker 4 to generate an additional sound having an opposite phase to the noise 6 propagating through the duct, thereby muffling the sound.

The muffled noise 6 propagating in the duct whose level has been reduced passes through the air outlet 5 installed in the living room 7 and propagates into the living room. At this time, the controller 3 has a function that allows you to freely change the volume and frequency characteristics of the additional sound that is in phase opposite to the noise.
By adjusting the silencing characteristics of the electronic silencing system 1, it is possible to freely set the low-noise air-conditioning noise 8 and the air-conditioning noise 9 including masking noise. The controller 3 is connected to a remote control switch 10 installed in the living room 7, and it is possible to adjust the silencing characteristics of the silencing system 1 according to the user's preferred operation. Additionally, the outputs of the two error microphones can be analyzed by the controller 3, and appropriate silencing characteristics can be automatically set.

The following two circuits are prepared as masking noise generation circuits from the additional sound speaker 4. The first is to adjust the generation accuracy of the additional sound, which can be generated by changing the phase characteristics and amplitude characteristics of the FIR adaptive filter 60 shown in FIG. 3 by setting the remote control switch 10.

The second is the operation of the masking noise generation dedicated circuit Ioo, and by setting the remote control switch 1o in FIG. 3, it is possible to generate noise by shorting the switch 101 and superimposing the masking noise signal on the silencing signal. . The masking noise generation dedicated circuit 100 can be easily configured using a noise generator, a graphic equalizer whose frequency characteristics can be freely set, or a digital filter and amplifier.

In addition, in FIG. 3, the symbols 30, 32, and 34 are amplifiers, and 50
is an A/D converter, 54 is a D/A converter, 70 is an arithmetic circuit, 8o is a feedback control filter, 90
is a delay correction filter.

This makes it possible to control the noise level in the living room 7 without newly installing speakers, audio equipment, etc. in the living room 7, and it is possible to create a desired sound environment in the room.

In the embodiment of the present invention, the level of the noise 6 propagating into the living room 7 is changed by remotely controlling the controller 3 of one electronic silencing system 1 to change the generated volume and frequency characteristics of the additional sound. Although we have explained how to
In the system, the main controller of the entire system may control the operation of the electronic silencing system 1 to control the silencing effect, and as a result, the level of noise propagating into the living room 7 may be changed.

〔Effect of the invention〕

It is possible to freely control the silencing effect of the electronic silencing system and obtain a desired sound environment.

・・Electronic sound deadening system, 2 A...Error microphone, 3 ...Additional sound speaker, 5 ...Noise, 7 ...Remote control switch.

...sensor microphone.

···controller.

...Air outlet.

···room.

Out wish Man Hitachi Plant Construction Co., Ltd.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram showing a conventional muffler, and FIG. 3 is a block diagram showing details of the embodiment of the present invention. Procedural amendment (, ¥N)

Claims (1)

[Claims] In an electronic silencing system that generates additional sound in the opposite phase to air conditioning noise in an air conditioning duct leading to a living room and muffles the sound by sonic interference, the controller is equipped with a function that can control the volume and frequency characteristics of the additional sound. An electronic silencing system characterized in that the silencing effect of the electronic silencing system can be freely controlled.