A noise suppression device and method

Abstract

The invention provides a noise suppressing device and a method thereof. The device is mainly composed of a cavity, a plurality of ducts, an electroacoustic sensor, a loudspeaker and a noise suppressing circuit; wherein, one duct is connected with the cavity so as to provide an external acoustic signal to enter the cavity; another duct is connected with the cavity so as to send the processed acoustic signal an ear canal; the electroacoustic sensor is used for receiving the acoustic wave signal which enters the cavity and converting thereof into an electronic signal and then sending thereof the noise suppressing circuit; the loudspeaker is used for receiving the electronic signal which is generated by the noise suppressing circuit and generating an opposite phase acoustic signal; the noise signal with high frequency can be suppressed by a low pass acoustic wave filter which is formed by the ducts and the cavity; the opposite phase acoustic wave signal has better noise suppressing effect to the noise with low frequency in the cavity; the invention achieves the object of noise resistance with full frequency by the effect synthesis of two noise suppressions.

Description

technical field [0001] The present invention relates to a noise suppression device and method, especially a device that combines a noise suppression circuit system and a cavity structure designed with an appropriate size. The noise suppression circuit generates anti-phase sound waves to suppress low-frequency noise. The above-mentioned cavity forms a low-pass acoustic wave filter to suppress high-frequency noise, so as to achieve the purpose of anti-noise at all frequencies. Background technique [0002] Long-term exposure to noise can easily lead to hearing loss in the ears, and excessive noise can make people feel uncomfortable. In recent years, due to the popularity of portable audio-visual equipment, the number of people who use headphones to listen to music has increased. When users are exposed to noisy environments, they often turn up the volume of the headphones because they cannot hear the sound of the outside world. damage to the eardrum. [0003] Taking earphone ...

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Problems solved by technology

[0002] Long-term exposure to noise can easily lead to hearing loss in the ears, and excessive noise can make people feel uncomfortable

In recent years, due to the popularity of portable audio-visual equipment, the number of people who use headphones to listen to music has increased. When users are exposed to noisy environments, they often turn up the volume of the headphones because they cannot hear the sound of the outside world. damage to the eardrum

[0003] Taking earphone products as an example, the earphones with noise suppression effect in general earphones can be roughly divided into earmuffs and earplugs. Traditional earmuffs usually have a bulky earmuff, and most of the earmuffs are made of Foam is used as a sound insulation material, and the user sets the earmuffs outside the ears, and the ears can be wrapped in the earmuffs, so as to prevent external noise from entering, but it is not conducive to carrying because of its bulky size; as for earphones, It can put the earphone into the ear, and through the tight fit formed between the earphone and the ear, the earphone can be fixed in the ear, and the external noise can be blocked. Although the earplug-like earphone has the advantage of being easy to carry, However, compared with the earmuff type earphones, although the sound insulation effect of the earplug type earphones is better, but because they are completely sealed, the air pressure will be unbalanced, and the so-called internal body noise will be heard, that is, when the user uses it, he will hear it. All kinds of internal sounds caused by talking, swallowing, or even the movement of body muscles and joints, and there is a feeling of suffocation and discomfort

[0004] Due to the poor sound insulation effect of the existing earmuff structure, there is a design combined with an active circuit design to filter out noise, such as the US Patent No. 4455675 "Head phoning". The said case first proposes a sound control system, which It is to generate sound waves through a sound sensing device to eliminate unwanted sound waves by interference. The above-mentioned type of technology is currently widely used by related industries, but the preferred applicable frequency range of the above-mentioned type of noise suppression method is a frequency range of several kHz The following low-frequency noise, and high-frequency noise, because the phase cannot be synchronized, resulting in poor anti-noise effect, it still needs to be eliminated by earmuffs; as for the patents of various countries that have been proposed in the later period to suppress noise, such as the US invention patent 4985925 No. "Active noise reduction system", the electronic components or their circuit layout may be different, but none of them can escape the design method of actively suppressing noise by the circuit, so high-frequency noise cannot be eliminated

[0005] Please refer to the U.S. Patent No. 6,683,965 "In-the-ear noise reduction headphones" shown in Fig. 1. The case proposes an earphone inserted into the ear canal, and the earphone has an outer casing 14, and the outer casing The body 14 includes an extension part 16 that can be put into the ear canal (not shown in the figure), and the outer shell 14 has an inner cavity 28, and the inner cavity 28 is connected to the passage 29 in the extension part 16. In the same way, its speaker 32 is configured in the channel 29, and the microphone 34 is configured in the space below the speaker 32 and the channel 29, through the configuration of the speaker 32 and the microphone 34, and the channel 29 and the ear canal to generate sound field coupling or transfer to achieve the purpose of reducing noise, but the cavity 28 and channel 29 have no filtering effect and cannot filter out high-frequency noise

[0006] Please refer to the Taiwan New Patent Application No. 91213715 "Feedback Active Noise Control Earphone" shown in Fig. On the contrary, the sound wave signal is then sensed by the microphone sensor 120 to detect the ambient noise of the speaker 110 and converted into a noise sensing signal, because the microphone sensor 120 is arranged in front of the speaker 110 and is located at the The front of the speaker 110 is in the energy vortex 150 generated in the earmuffs 140 due to the near-field effect, so it can suppress the reception of low-frequency noise, and can cancel each other with the anti-phase sound waves generated by the speaker 110; For low-frequency noise cancellation, the location of the microphone sensor 120 is limited to the front of the speaker 110, and the earmuffs 140 and the active noise control circuit 130 must be matched at the same time.

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