A multi-frequency independent processing noise reduction headphone and its noise reduction method

Abstract

The present invention discloses a multi-frequency independent processing noise-canceling headphone and its noise-canceling method. The multi-frequency independent processing noise-canceling headphone includes a rear shell, a middle cover, and a front cover that are sequentially installed. At least two mutually isolated frequency-dividing cavities are formed between the rear shell and the middle cover. A first microphone and a first low-pass filter for low-frequency phase extraction are provided in one of the frequency-dividing cavities, and a third microphone and a high-pass filter for high-frequency phase extraction are provided in one of the frequency-dividing cavities. An out-sound chamber that is in communication with all the frequency-dividing cavities is further formed between the front cover and the middle cover. A fourth microphone and a third low-pass filter for filtering residues of the mixed signal are provided in the out-sound chamber. A first speaker and a third speaker for outputting audio are further provided at the rear side of the middle cover, and the rear ends of the first speaker and the third speaker are respectively placed in one of the frequency-dividing cavities. The first microphone, the first low-pass filter, the third microphone, the high-pass filter, the fourth microphone, the third low-pass filter, the first speaker, and the third speaker are all connected to a controller.

Description

Technical Field:

[0001] The present invention relates to the technical field of headphone products, and particularly to a multi-frequency independent processing noise-canceling headphone and a noise-canceling method thereof. Background Art:

[0002] A headphone is a pair of transducer units that receive electrical signals emitted by a media player or receiver and convert them into audible sound waves using speakers close to the ears. As a sound listening device, headphones have been widely used in various industries, and they have the advantages of being inexpensive, small, convenient to use, and not disturbing others. Common headphones include several types such as over-ear, ear-hook, and in-ear types, with a wide variety of varieties and appearances.

[0003] Currently, most headphones generally perform noise-canceling processing to improve sound quality. Specifically, currently, most headphones generally set up a chamber to install speakers, and use a microphone to collect noise, and cooperate with a low-pass filter or a high-pass filter to filter out noise. When using a low-pass filter, between frequencies 0 to f2, the amplitude-frequency characteristic is flat. It can make the part of the signal below f2 pass through with almost no attenuation. The IIR algorithm filter can effectively extract and reverse-process to cancel the noise part, while the frequency part above f2 is greatly attenuated, and the IIR algorithm filter cannot extract and reverse-process the remaining noise. When using a high-pass filter, it is the opposite of the low-pass filter. From frequency f1 to ∞, its amplitude-frequency characteristic is flat. It allows the frequency part of the signal above f1 to pass through without attenuation, while the frequency part below f1 will be greatly attenuated, and the algorithm filter cannot extract the noise source for reverse cancellation processing.

[0004] That is to say, currently, headphones can only process high-frequency noise or low-frequency noise. When filtering out high-frequency noise, low-frequency noise will remain, and when filtering out low-frequency noise, high-frequency noise will remain, that is, it is impossible to simultaneously remove high-frequency noise and low-frequency noise, resulting in a clean music signal output, affecting sound quality, and being disadvantageous for improving market competitiveness.

[0005] In view of this, the inventor of the present invention proposes the following technical solutions. Summary of the Invention:

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a multi-frequency independent processing noise-canceling headphone and a noise-canceling method thereof.

[0007] To solve the above technical problems, the present invention adopts the following first technical solution: The multi-frequency independent processing noise-canceling earphone includes a rear shell, a middle cover disposed at the front end of the rear shell, and a front cover mounted at the front end of the middle cover. At least two mutually isolated frequency-dividing cavities are formed between the rear shell and the middle cover. A first microphone and a first low-pass filter for low-frequency phase extraction are disposed in one of the frequency-dividing cavities, and a third microphone and a high-pass filter for high-frequency phase extraction are disposed in one of the frequency-dividing cavities. An out-sound chamber communicating with all the frequency-dividing cavities is further formed between the front cover and the middle cover. A fourth microphone and a third low-pass filter for filtering residues of the mixed signal are disposed in the out-sound chamber. A first speaker and a third speaker for outputting audio are further disposed at the rear side of the middle cover, and the rear ends of the first speaker and the third speaker are respectively placed in one of the frequency-dividing cavities. The first microphone, the first low-pass filter, the third microphone, the high-pass filter, the fourth microphone, the third low-pass filter, the first speaker, and the third speaker are all connected to a controller.

[0008] Furthermore, in the above technical solution, the number of the frequency-dividing cavities is three, namely a bass cavity, a midrange cavity, and a treble cavity. The first microphone and the first low-pass filter are disposed in the bass cavity. A second microphone and a second low-pass filter for mid-frequency phase extraction are disposed in the midrange cavity, and the third microphone and the high-pass filter are disposed in the treble cavity. A second speaker for outputting audio is further disposed at the rear side of the middle cover, and the second speaker is in the midrange cavity. The rear ends of the first speaker and the third speaker are respectively placed in the bass cavity and the treble cavity. The second microphone, the second low-pass filter, and the second speaker are all connected to the controller.

[0009] Furthermore, in the above technical solution, the outer periphery of the rear shell is provided with a first perforation, a second perforation, and a third perforation respectively communicating with the bass cavity, the midrange cavity, and the treble cavity, and a first tuning net, a second tuning net, and a third tuning net are respectively disposed in the first perforation, the second perforation, and the third perforation.

[0010] Furthermore, in the above technical solution, the midrange cavity and the treble cavity have the same size, and both are smaller than the size of the bass cavity.

[0011] Furthermore, in the above technical solution, the rear shell is formed with mutually isolated bass grooves, midrange grooves, and treble grooves. After the bass grooves, midrange grooves, and treble grooves are respectively butted with the middle cover, the bass cavity, the midrange cavity, and the treble cavity are formed. First card slots, second card slots, and third card slots are respectively formed at the bottoms of the bass grooves, midrange grooves, and treble grooves, and the first microphone, the second microphone, and the third microphone are respectively clamped and fixed in the first card slot, the second card slot, and the third card slot.

[0012] Furthermore, in the above technical solution, a first installation groove, a second installation groove, and a third installation groove that are isolated from each other are further provided at the rear side of the middle cover. Three first through holes, second through holes, and third through holes that respectively penetrate the first installation groove, the second installation groove, and the third installation groove are opened from the front end of the middle cover backward. The first speaker, the second speaker, and the third speaker are respectively disposed in the first installation groove, the second installation groove, and the third installation groove.

[0013] Furthermore, in the above technical solution, the front cover is provided with a plurality of sound outlet holes communicating with the sound outlet chamber, and an installation ring is provided at the rear side of the front cover. The fourth microphone is snap-fitted and installed in the installation ring.

[0014] Furthermore, in the above technical solution, the controller includes a DSP chip. A DPS module, a power management module connected to the DPS module, a register for connecting music input, an AGC module for adjusting the microphone gain, and several operational amplifiers are integrated in the DSP chip. The first low-pass filter, the second low-pass filter, the high-pass filter, the third low-pass filter, the first speaker, the second speaker, and the third speaker are respectively connected to an operational amplifier and then connected to the DPS module. The first microphone, the second microphone, the third microphone, and the fourth microphone are all connected to a comparator and then connected to the DPS module. A reserved port for controlling its on and off operations and communicating with other chips is integrated in the DSP chip.

[0015] To solve the above technical problems, the present invention adopts the following second technical solution: The noise reduction method of the multi-frequency independent processing noise reduction earphone is as follows: At least two mutually isolated frequency division cavities and a sound outlet chamber communicating with the frequency division cavities are provided inside the earphone. A first microphone and a first low-pass filter are provided in the first frequency division cavity to collect noise sources and filter high-frequency noise, and the high-frequency phase signal is sent to the DSP chip. A third microphone and a high-pass filter are provided in the second frequency division cavity to collect noise sources and filter low-frequency noise, and the low-frequency phase signal is sent to the DSP chip. The DSP chip performs phase superposition on the sent high-frequency and low-frequency phase signals and mixes them with the music signal. Then, the residual noise in the mixed signal is filtered by the fourth microphone and the third low-pass filter in the sound outlet chamber. Finally, a clean music signal is output through the speaker.

[0016] Furthermore, in the above technical solution, the number of the frequency division cavities is three. A second microphone and a second low-pass filter are provided in the third frequency division cavity to collect noise sources and filter high-frequency noise and low-frequency noise to extract the intermediate frequency phase and send it to the DSP chip. The DSP chip performs phase superposition on the sent high-frequency, intermediate-frequency, and low-frequency phase signals and mixes them with the music signal.

[0017] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art: The present invention overcomes the defects of the prior art of using low-pass filters or high-pass filters alone. By using an acoustic architecture design with independent frequency division and implementing a hybrid filter through algorithm extraction and integration, it avoids interference between upper frequency bands during algorithm extraction, ensuring a clean music signal output and giving the present invention strong market competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS:

[0018] Figure 1 is a perspective view of the present invention;

[0019] Figure 2 is a perspective view of the present invention from another perspective;

[0020] Figure 3 is an exploded perspective view of the present invention;

[0021] Figure 4 is a cross-sectional view of the present invention;

[0022] Figure 5 is a cross-sectional view of the present invention from another perspective;

[0023] Figure 6 is an internal structure diagram of the present invention;

[0024] Figure 7 is a perspective view of the rear shell of the present invention;

[0025] Figure 8 is a perspective view of the middle cover of the present invention;

[0026] Figure 9 is a perspective view of the front shell of the present invention;

[0027] Figure 10 is a circuit diagram of the present invention;

[0028] Figure 11 is a circuit schematic diagram of the present invention. DETAILED DESCRIPTION OF THE INVENTION:

[0029] The present invention will be further described below in conjunction with specific embodiments and the accompanying drawings.

[0030] See Figures 1-11As shown in the figure, it is a multi - frequency independent processing noise - cancelling headphone, which includes a rear shell 1, a middle cover 2 arranged at the front end of the rear shell 1, and a front cover 3 installed at the front end of the middle cover 2. At least two mutually isolated frequency - dividing cavities are formed between the rear shell 1 and the middle cover 2 to achieve an acoustic architecture design of independent frequency - division. A first microphone 41 for low - frequency phase extraction and a first low - pass filter 42 are arranged in one of the frequency - dividing cavities, and a third microphone 45 for high - frequency phase extraction and a high - pass filter 46 are arranged in another frequency - dividing cavity; An out - sound chamber 30 communicating with all the frequency - dividing cavities is further formed between the front cover 3 and the middle cover 2. A fourth microphone 301 for filtering residues of the mixed signal and a third low - pass filter 302 are arranged in the out - sound chamber 30; A first speaker 51 and a third speaker 53 for outputting audio are further arranged at the rear side of the middle cover 2, and the rear ends of the first speaker 51 and the third speaker 53 are respectively placed in a frequency - dividing cavity; The first microphone 41, the first low - pass filter 42, the third microphone 45, the high - pass filter 46, the fourth microphone 301, the third low - pass filter 302, the first speaker 51 and the third speaker 53 are all connected to a controller. In the present invention, at least two mutually isolated and exchangeable frequency - dividing cavities and an out - sound chamber communicating with the frequency - dividing cavities are provided inside the headphone. A first microphone and a first low - pass filter are arranged in the first frequency - dividing cavity to collect the noise source and filter high - frequency noise, and send the high - frequency phase signal to the DSP chip; A third microphone and a high - pass filter are arranged in the second frequency - dividing cavity to collect the noise source and filter low - frequency noise, and send the low - frequency phase signal to the DSP chip; The DSP chip performs phase superposition on the input high - and low - frequency phase signals and mixes them with the music signal, and then the fourth microphone and the third low - pass filter in the out - sound chamber filter the residual noise in the mixed signal, and finally a clean music signal is output through the speaker. That is to say, in the present invention, the low - pass filter and the high - pass filter are used in combination. Combining with the acoustic mechanism (i.e., the frequency - dividing cavity), a two - frequency (or multi - frequency) low - frequency and high - frequency independent unit is used as frequency - division. The low - pass filter serves as the low - frequency unit to extract low - frequency noise and perform reverse cancellation processing, and the high - pass filter serves as the high - frequency unit to extract and perform reverse cancellation processing on the residual noise, realizing the function of a hybrid filter. And later, the DSP chip performs phase superposition on the high - and low - frequency phase signals and mixes them with the music signal, and then the low - pass filter filters the residual noise in the mixed signal, and finally a clean music signal is output through the speaker. The present invention overcomes the defects of the existing technology of using a low - pass filter or a high - pass filter alone, uses an acoustic architecture design of independent frequency - division, and uses algorithm extraction and integration to realize a hybrid filter, avoiding interference between frequency bands in algorithm extraction, ensuring the output of a clean music signal, and making the present invention have extremely strong market competitiveness.

[0031] The number of the frequency division cavities is three, namely a bass cavity 101, a midrange cavity 102 and a treble cavity 103. The first microphone 41 and the first low-pass filter 42 are arranged in the bass cavity 101; a second microphone 43 and a second low-pass filter 44 for mid-frequency phase extraction are arranged in the midrange cavity 102; the third microphone 45 and a high-pass filter 46 are arranged in the treble cavity 103; a second speaker 52 for outputting audio is further arranged at the rear side of the middle cover 2, and the second speaker 52 is arranged in the midrange cavity 102; the rear ends of the first speaker 51 and the third speaker 53 are respectively arranged in the bass cavity 101 and the treble cavity 103; the second microphone 43, the second low-pass filter 44 and the second speaker 52 are all connected to a controller. The present invention adds the second microphone 43 and the second low-pass filter 44, and the second microphone 43 and the second low-pass filter 44 are used for mid-frequency phase extraction, filter out high and low frequency noises, and retain mid-frequency signals, so as to perform phase superposition on high, mid and low frequency phase signals through a DSP chip in the later stage, and ensure the quality of noise filtering.

[0032] A first through hole 11, a second through hole 12 and a third through hole 13 which are respectively communicated with the bass cavity 101, the midrange cavity 102 and the treble cavity 103 are arranged on the periphery of the rear shell 1, and a first tuning net 111, a second tuning net 112 and a third tuning net 113 are respectively arranged in the first through hole 11, the second through hole 12 and the third through hole 13, and the frequencies of the bass cavity 101, the midrange cavity 102 and the treble cavity 103 are independently adjusted through the first tuning net 111, the second tuning net 112 and the third tuning net 113.

[0033] The midrange cavity 102 and the treble cavity 103 are the same in size and both are smaller than the size of the bass cavity 101, so that better frequency division processing of low frequency, mid frequency and high frequency can be realized.

[0034] The rear housing 1 is formed with a bass groove 14, a midrange groove 15 and a treble groove 16 that are isolated from each other. After the bass groove 14, the midrange groove 15 and the treble groove 16 are respectively docked with the middle cover 2, the bass cavity 101, the midrange cavity 102 and the treble cavity 103 are formed. The bottoms of the bass groove 14, the midrange groove 15 and the treble groove 16 are respectively formed with a first card slot 141, a second card slot 151 and a third card slot 161. The first microphone 41, the second microphone 43 and the third microphone 45 are respectively snap-fitted and fixed in the first card slot 141, the second card slot 151 and the third card slot 161, so as to ensure the stability of the assembly of the first microphone 41, the second microphone 43 and the third microphone 45, and ensure the quality of the frequency division design. Further, the rear side of the middle cover 2 is also provided with a first mounting groove 21, a second mounting groove 22 and a third mounting groove 23 that are isolated from each other. The front end of the middle cover 2 is provided with three groups of first through holes 24, second through holes 25 and third through holes 26 that respectively penetrate the first mounting groove 21, the second mounting groove 22 and the third mounting groove 23. The first speaker 51, the second speaker 52 and the third speaker 53 are respectively arranged in the first mounting groove 21, the second mounting groove 22 and the third mounting groove 23, so as to ensure the stability of the assembly of the first speaker 51, the second speaker 52 and the third speaker 53.

[0035] The front cover 3 is provided with a plurality of sound outlet holes 31 communicating with the sound outlet chamber 30, and an installation ring 32 is arranged at the rear side of the front cover 3. The fourth microphone 301 is snap-fitted and installed in the installation ring 32.

[0036] The controller includes a DSP chip 6. The DSP chip 6 is integrated with a DPS module 61, a power management module 62 connected to the DPS module 61, a register 63 for connecting music input, an AGC module 64 for adjusting the microphone gain, and a number of operational amplifiers 65. The first low-pass filter 42, the second low-pass filter 44, the high-pass filter 46, the third low-pass filter 302, the first speaker 51, the second speaker 52 and the third speaker 53 are respectively connected to an operational amplifier 65 and then connected to the DPS module 61. The first microphone 41, the second microphone 43, the third microphone 45 and the fourth microphone 301 are all connected to a comparator and then connected to the DPS module 61. The DSP chip 6 is integrated with a reserved port 66 for controlling its on and off operations and for communicating with other chips.

[0037] In summary, the present invention provides at least two mutually isolated and exchangeable frequency-dividing cavities inside the earphone and a sound output cavity communicating with the frequency-dividing cavities. A first microphone and a first low-pass filter are arranged in the first frequency-dividing cavity to collect noise sources and filter high-frequency noise, and send the high-frequency phase signal to the DSP chip; a third microphone and a high-pass filter are arranged in the second frequency-dividing cavity to collect noise sources and filter low-frequency noise, and send the low-frequency phase signal to the DSP chip; the DSP chip performs phase superposition on the sent high-frequency and low-frequency phase signals and mixes them with the music signal, and then the fourth microphone and the third low-pass filter in the sound output cavity filter the residual noise in the mixed signal, and finally a clean music signal is output through the speaker. That is to say, the present invention combines the use of a low-pass filter and a high-pass filter, and uses a two-way frequency division (or multi-way frequency division) low-frequency and high-frequency independent unit as frequency division in combination with an acoustic mechanism (i.e., a frequency-dividing cavity). The low-pass filter serves as the low-frequency unit to extract and perform reverse cancellation processing on low-frequency noise, and the high-pass filter serves as the high-frequency unit to extract and perform reverse cancellation processing on residual noise, realizing the function of a hybrid filter. And later, the DSP chip performs phase superposition on the high-frequency and low-frequency phase signals and mixes them with the music signal, and then the low-pass filter filters the residual noise in the mixed signal, and finally a clean music signal is output through the speaker. The present invention overcomes the defects of the prior art of using a low-pass filter or a high-pass filter alone, uses an acoustic architecture design with independent frequency division, and uses algorithm extraction and integration to realize a hybrid filter, avoiding interference between frequency bands in algorithm extraction, ensuring the output of a clean music signal, and making the present invention highly competitive in the market.

[0038] The present invention also provides a noise reduction method for a multi-way frequency division independent processing noise reduction earphone. The noise reduction method is as follows: at least two mutually isolated and exchangeable frequency-dividing cavities and a sound output cavity communicating with the frequency-dividing cavities are provided inside the earphone. A first microphone 41 and a first low-pass filter 42 are arranged in the first frequency-dividing cavity to collect noise sources and filter high-frequency noise, and send the high-frequency phase signal to the DSP chip; a third microphone 45 and a high-pass filter 46 are arranged in the second frequency-dividing cavity to collect noise sources and filter low-frequency noise, and send the low-frequency phase signal to the DSP chip; the DSP chip performs phase superposition on the sent high-frequency and low-frequency phase signals and mixes them with the music signal, and then the fourth microphone 301 and the third low-pass filter 302 in the sound output cavity filter the residual noise in the mixed signal, and finally a clean music signal is output through the speaker. The present invention overcomes the defects of the prior art of using a low-pass filter or a high-pass filter alone, uses an acoustic architecture design with independent frequency division, and uses algorithm extraction and integration to realize a hybrid filter, avoiding interference between frequency bands in algorithm extraction, ensuring the output of a clean music signal, and making the present invention highly competitive in the market.

[0039] The number of the frequency division cavities is three. The third frequency division cavity is provided with a second microphone 43 and a second low-pass filter 44 for collecting the noise source and filtering high-frequency noise and low-frequency noise so as to extract the intermediate-frequency phase and send it to the DSP chip. The DSP chip performs phase superposition on the sent high-, medium- and low-frequency phase signals and then mixes them with the music signal. The noise reduction method of the multi-frequency division independent processing noise reduction earphone of the present invention further adds a second microphone 43 and a second low-pass filter 44 for collecting the noise source and filtering high-frequency noise and low-frequency noise so as to extract the intermediate-frequency phase, so that the DSP chip can perform phase superposition on the high-, medium- and low-frequency phase signals in the later stage, further ensuring the quality of noise filtering.

[0040] Certainly, the above are only specific embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Any equivalent changes or modifications made according to the structure, features and principles described in the scope of the patent application of the present invention shall be included in the scope of the patent application of the present invention.

Claims

1. A multi-frequency independent processing noise-canceling headphone, characterized in that: It includes a rear shell (1), a middle cover (2) disposed at the front end of the rear shell (1), and a front cover (3) mounted at the front end of the middle cover (2). At least two mutually isolated frequency division cavities are formed between the rear shell (1) and the middle cover (2). A first microphone (41) for low-frequency phase extraction and a first low-pass filter (42) are disposed in one of the frequency division cavities. A third microphone (45) for high-frequency phase extraction and a high-pass filter (46) are disposed in one of the frequency division cavities. An acoustic chamber (30) communicating with all the frequency division cavities is further formed between the front cover (3) and the middle cover (2). A fourth microphone (301) for filtering residues of the mixed signal and a third low-pass filter (302) are disposed in the acoustic chamber (30). A first speaker (51) and a third speaker (53) for outputting audio are further disposed at the rear side of the middle cover (2). The rear ends of the first speaker (51) and the third speaker (53) are respectively placed in a frequency division cavity. The first microphone (41), the first low-pass filter (42), the third microphone (45), the high-pass filter (46), the fourth microphone (301), the third low-pass filter (302), the first speaker (51), and the third speaker (53) are all connected to a controller.

2. The multi-frequency independent processing noise-canceling earphone according to claim 1, wherein: The number of the frequency division cavities is three, namely a bass cavity (101), a midrange cavity (102), and a treble cavity (103). The first microphone (41) and the first low-pass filter (42) are disposed in the bass cavity (101). A second microphone (43) for mid-frequency phase extraction and a second low-pass filter (44) are disposed in the midrange cavity (102). The third microphone (45) and the high-pass filter (46) are disposed in the treble cavity (103). A second speaker (52) for outputting audio is further disposed at the rear side of the middle cover (2). The second speaker (52) is in the midrange cavity (102). The rear ends of the first speaker (51) and the third speaker (53) are respectively placed in the bass cavity (101) and the treble cavity (103). The second microphone (43), the second low-pass filter (44), and the second speaker (52) are all connected to a controller.

3. The multi-frequency independent processing noise reduction earphone according to claim 2, wherein: First perforations (11), second perforations (12), and third perforations (13) respectively communicating with the bass cavity (101), the midrange cavity (102), and the treble cavity (103) are disposed on the periphery of the rear shell (1). A first tuning net (111), a second tuning net (112), and a third tuning net (113) are respectively disposed in the first perforation (11), the second perforation (12), and the third perforation (13).

4. The multi-frequency independent processing noise-canceling earphone according to claim 2, wherein: The midrange cavity (102) and the treble cavity (103) have the same size and are both smaller than the size of the bass cavity (101).

5. The multi-frequency independent processing noise-canceling earphone according to claim 2, wherein: The rear shell (1) is formed with a bass groove (14), a midrange groove (15), and a treble groove (16) that are isolated from each other. After the bass groove (14), the midrange groove (15), and the treble groove (16) are respectively docked with the middle cover (2), the bass cavity (101), the midrange cavity (102), and the treble cavity (103) are formed. The bottoms of the bass groove (14), the midrange groove (15), and the treble groove (16) are respectively formed with a first card slot (141), a second card slot (151), and a third card slot (161). The first microphone (41), the second microphone (43), and the third microphone (45) are respectively snap-fitted and fixed in the first card slot (141), the second card slot (151), and the third card slot (161).

6. A multi-frequency independent processing noise reduction headphone according to claim 2, characterized in that: On the rear side of the middle cover (2), there are also provided a first installation groove (21), a second installation groove (22), and a third installation groove (23) that are isolated from each other. At the front end of the middle cover (2), three groups of first through holes (24), second through holes (25), and third through holes (26) that respectively penetrate the first installation groove (21), the second installation groove (22), and the third installation groove (23) are opened backward. The first speaker (51), the second speaker (52), and the third speaker (53) are respectively disposed in the first installation groove (21), the second installation groove (22), and the third installation groove (23).

7. A multi-frequency independent processing noise-canceling headphone according to any one of claims 2-5, characterized in that: The front cover (3) is provided with a plurality of sound outlet holes (31) of the sound outlet chamber (30), and an installation ring (32) is provided on the rear side of the front cover (3). The fourth microphone (301) is snap-fitted and installed in the installation ring (32).

8. The multi-frequency independent processing noise reduction earphone according to claim 6, characterized in that: The controller includes a DSP chip (6). The DSP chip (6) is integrated with a DPS module (61), a power management module (62) connected to the DPS module (61), a register (63) for connecting music input, an AGC module (64) for adjusting the microphone gain, and a number of operational amplifiers (65). The first low-pass filter (42), the second low-pass filter (44), the high-pass filter (46), the third low-pass filter (302), the first speaker (51), the second speaker (52), and the third speaker (53) are respectively connected to an operational amplifier (65) and then connected to the DPS module (61). The first microphone (41), the second microphone (43), the third microphone (45), and the fourth microphone (301) are all connected to a comparator and then connected to the DPS module (61). The DSP chip (6) is integrated with a reserved port (66) for controlling its on and off operations and for communicating with other chips.

9. A noise reduction method for a multi-frequency independent processing noise reduction headphone, characterized in that: The noise reduction method is as follows: There are at least two mutually isolated and exchangeable frequency division cavities inside the earphone and a sound output chamber communicated with the frequency division cavities. A first microphone (41) and a first low-pass filter (42) are arranged in the first frequency division cavity to collect the noise source and filter high-frequency noise, and send the high-frequency phase signal to the DSP chip; A third microphone (45) and a high-pass filter (46) are arranged in the second frequency division cavity to collect the noise source and filter low-frequency noise, and send the low-frequency phase signal to the DSP chip; The DSP chip performs phase superposition on the input high-frequency and low-frequency phase signals and mixes them with the music signal, and then the fourth microphone (301) and the third low-pass filter (302) in the sound output chamber filter the residual noise in the mixed signal, and finally a clean music signal is output through the speaker.

10. The noise reduction method of a multi-frequency independent processing noise reduction headphone according to claim 9, characterized in that: The number of the frequency division cavities is three. A second microphone (43) and a second low-pass filter (44) are arranged in the third frequency division cavity to collect the noise source and filter high-frequency noise and low-frequency noise, so as to extract the intermediate-frequency phase and send it to the DSP chip. The DSP chip performs phase superposition on the input high-frequency, intermediate-frequency and low-frequency phase signals and mixes them with the music signal.

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