Active noise reduction Bluetooth headphone based on adjustable sound cavity rear cavity

Abstract

The utility model relates to an active noise reduction Bluetooth headphone based on an adjustable sound cavity rear cavity, a cavity is arranged in a shell of a headphone main body, a loudspeaker is arranged in the cavity, and the cavity is divided into a front cavity and a rear cavity by the loudspeaker; the shell is provided with a tuning channel communicated with the rear cavity, a valve used for opening or closing the tuning channel and a feed-forward microphone used for capturing external environment noise; a feedback microphone used for detecting residual noise actually entering the ears is arranged at the front cavity, and a main control unit used for conducting active noise reduction according to external environment noise and the residual noise actually entering the ears is further arranged in the earphone body. According to the utility model, through cooperation of the adjustable rear cavity and active noise reduction, the inherent contradiction between an open type earphone and a closed type earphone is solved, and the earphone has sound field naturalness, low-frequency impact force and active noise reduction capability. The structure is simple, the practicability is high, the diversity requirements of music types and use scenes are considered, and the use performance is improved.

Description

Technical Field

[0001] This utility model relates to the field of headphone technology, and in particular to Bluetooth headphones. Background Technology

[0002] Bluetooth headphones are worn directly on the user's head and cover the ears, with sound output through the headphones themselves. They are typically used for high-quality audio listening, such as music, games, or professional audio production. Bluetooth headphones come in two types: open-back and closed-back. Open-back headphones offer a natural soundstage but have poor noise isolation, while closed-back headphones deliver powerful bass but a narrow soundstage. Users need to choose the appropriate device based on the scenario. Furthermore, the fixed-cavity design cannot accommodate the diverse needs of different music genres and usage scenarios. Although some headphones incorporate ANC (Active Noise Cancellation) technology to compensate for the lack of sound isolation, they cannot solve the low-frequency leakage problem caused by the open-back design.

[0003] Therefore, a new technical solution needs to be researched to address the above problems. Summary of the Invention

[0004] The purpose of this invention is to provide an active noise-canceling Bluetooth headset based on an adjustable acoustic cavity rear chamber, which can effectively solve the above-mentioned technical problems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An active noise-canceling Bluetooth headset based on an adjustable acoustic cavity rear chamber includes a headband and two earphone bodies mounted on the headband. The two earphone bodies are positioned facing each other and are fitted to the user's left and right ears when worn. Each earphone body has a shell; the shell contains a cavity and a speaker, which divides the cavity into a front cavity closer to the user's ear and a rear cavity further away from the user's ear. The shell has a tuning channel communicating with the rear cavity, a valve for opening or closing the tuning channel, and a feedforward microphone for capturing external ambient noise. A feedback microphone is located in the front cavity for detecting residual noise actually entering the ear. The earphone body also contains a main control unit for active noise cancellation based on external ambient noise and residual noise actually entering the ear.

[0007] The above solution is further described as follows: the shell is composed of an inner liner and an outer shell, with the main control unit embedded between the inner liner and the outer shell; the inner liner has a cavity built inside, and a first through hole is opened on the inner liner to connect with the rear cavity, and a second through hole is opened on the outer shell to connect with the first through hole, and the first through hole and the second through hole are connected to form a tuning channel; the valve opens or closes the tuning channel by opening or closing the relationship between the first through hole and the second through hole.

[0008] The above solution further includes a door panel that is embedded between the first through hole and the second through hole and can slide, and an actuating member that connects the door panel and extends out of the housing. The actuating member moves back and forth along a pre-set guide groove on the housing and drives the door panel to slide, so that the door panel is inserted between the first through hole and the second through hole to cut off the connection between the first through hole and the second through hole, or to move the door panel out from between the first through hole and the second through hole to open the connection between the first through hole and the second through hole.

[0009] Furthermore, the valve supports multi-stage switching modes.

[0010] The above solution further includes an ANC circuit in the main control unit, and the active noise reduction of the main control unit includes:

[0011] When the tuning channel is open, the rear cavity is in open mode, and the main control unit enhances low-frequency compensation and cancels low-frequency loss caused by sound leakage.

[0012] When the tuning channel is closed, the rear cavity is in a sealed mode, and the main control unit increases the high-frequency noise reduction depth to suppress cavity resonance.

[0013] A further improvement in the above solution is that the feedforward microphone is hidden inside the housing and captures external environmental noise through pre-set vents in the housing.

[0014] A further improvement of the above scheme is that the interior of the cavity within the housing is designed as a spiral structure with frequency-dividing and flow-guiding effects.

[0015] By employing the aforementioned structure, this invention resolves the inherent contradictions between open-back and closed-back headphones through the coordinated use of an adjustable rear cavity and active noise cancellation, achieving a balance between natural soundstage, powerful low-frequency response, and active noise cancellation. The valve opens or closes the tuning channel, enabling rapid switching between open-back (free airflow) and closed-back (completely sealed) modes. An open rear cavity allows free airflow, preventing sound waves from being completely reflected or absorbed, thus reducing resonance and standing wave interference. This results in a wider and more natural soundstage with a stronger sense of space, clearer instrument positioning, and the sound not being muffled within the earcups. Conversely, a completely sealed rear cavity results in sound waves being absorbed or isolated after multiple reflections within the cavity. This leads to a narrower soundstage, a focused sound but a lack of spatial depth, and powerful low frequencies.

[0016] This utility model has a simple structure, strong practicality, and takes into account the diverse needs of music genres and usage scenarios, thereby improving performance. Attached Figure Description

[0017] Appendix Figure 1 This is a schematic diagram of a preferred embodiment of the present invention;

[0018] Appendix Figure 2 for Figure 1 A schematic diagram of the main structure of the earphone in the embodiment;

[0019] Appendix Figure 3 for Figure 2 A schematic diagram of the internal local structure distribution;

[0020] Appendix Figure 4 for Figure 2 A cross-sectional view of the internal structure. Detailed Implementation

[0021] The following will further explain the concept, specific structure and technical effects of the utility model in conjunction with the accompanying drawings, so as to fully understand the purpose, features and effects of the utility model.

[0022] It should be noted that in the description of this utility model, the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate directional or positional relationships, are based on the directional or positional relationships shown in the accompanying drawings. These terms are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] See Figure 1 , 2 Figures 3 and 4 show schematic diagrams of a preferred embodiment of this utility model. This utility model relates to an active noise-canceling Bluetooth headset based on an adjustable acoustic cavity rear chamber, comprising a headband 1 and two earphone bodies 2 mounted on the headband 1. The two earphone bodies are arranged facing each other and fit the user's left and right ears during use. The headband 1 and earphone bodies 2 are hinged together, allowing relative rotation, and the telescopic characteristics of the headband 1 enhance wearing convenience and comfort. Each earphone body 2 has a shell 21 and earcups 26 mounted on the shell. The earcups 26 are designed to fit the user's ears, increasing wearing comfort and listening experience. The housing 21 has a cavity inside, and a speaker 22 is installed in the cavity. The speaker divides the cavity into a front cavity 211 close to the user's ear and a rear cavity 212 away from the user's ear. The housing 21 has a tuning channel that connects to the rear cavity 212, a valve 23 for opening or closing the tuning channel, and a feedforward microphone 24 for capturing external ambient noise. A feedback microphone 25 for detecting residual noise that actually enters the ear is provided in the front cavity 211. The headphone body 2 also has a main control unit 3 for active noise cancellation based on external ambient noise and residual noise that actually enters the ear.

[0024] Main control unit 3 includes an ANC circuit. The active noise reduction of the main control unit includes:

[0025] When the tuning channel is open, the rear cavity is in open mode. The main control unit enhances low-frequency compensation and cancels low-frequency loss caused by sound leakage. The feedforward microphone 24 collects signals before noise enters the ear canal and transmits them to the main control unit 3. The ANC circuit generates an inverse sound wave (opposite phase), which is played by the speaker of the headphone body to cancel the noise that is about to enter the ear.

[0026] When the tuning channel is closed, the rear cavity is in a sealed mode, and the main control unit optimizes the high-frequency noise reduction depth and suppresses cavity resonance. The feedback microphone 25 collects the mixed signal (original noise + reverse sound wave) in the ear canal and transmits it to the main control unit 3. The reverse sound wave parameters are adjusted in real time through the closed-loop control of the ANC circuit to dynamically optimize the noise reduction effect.

[0027] This invention introduces a valve to open or close the rear cavity, achieving adjustable rear cavity design. This allows it to cater to diverse needs across music genres and usage scenarios, offering multiple uses in one device. Users no longer need to select different devices for different situations, enhancing practicality. Furthermore, the use of ANC technology resolves the inherent contradictions between open-back and closed-back headphones, combining a natural soundstage, powerful bass, and active noise cancellation.

[0028] Figure 2 , 3 As shown in Figure 4, the housing 21 is composed of an inner liner 213 and an outer shell 214. The main control unit 3 is embedded between the inner liner 213 and the outer shell 214 and is electrically connected to the feedforward microphone 24 and the feedback microphone 25. The inner liner 213 has an internal cavity and a first through hole 2131 that connects to the rear cavity 212. The outer shell 214 has a second through hole 2141 that connects to the first through hole 2131. The first through hole 2131 and the second through hole 2141 are connected to form a tuning channel. The valve 23 opens or closes the tuning channel by opening or closing the relationship between the first through hole 2131 and the second through hole 2141.

[0029] Furthermore, the valve 23 includes a door panel 231 that is embedded between the first through hole 2131 and the second through hole 2141 and can slide, and an actuating member 232 that connects the door panel and extends from the housing 21. In this embodiment, the door panel 231 and the actuating member 232 are integrally constructed into a U-shape. The door panel 231 is inserted into the reserved interlayer between the inner liner 213 and the outer shell 214, and is precisely embedded between the first through hole 2131 and the second through hole 2141. After the door panel 231 is installed, at least the inner side is tightly fitted with the contour of the inner liner 213, which satisfies the requirement of sealing the first through hole 2131. The actuating element 232 is a protruding pin that can reciprocate along a pre-set guide groove 215 on the housing 21, thereby driving the door panel 231 to slide. This allows the door panel 231 to be inserted between the first through hole 2131 and the second through hole 2141 to cut off the connection between the two holes, or to move the door panel 231 out of the space between the first through hole 2131 and the second through hole 2141 to open the connection. In this embodiment, the valve 23 supports multi-level switching modes, meaning that the degree to which the door panel 231 covers the first through hole 2131 achieves multiple opening levels (such as semi-open or semi-closed), adapting to different music genres and ambient noise levels.

[0030] In this embodiment, the feedforward microphone 24 is hidden inside the housing 21 and captures external ambient noise through a pre-set vent 216 in the housing 21. The structure is simple, easy to manufacture and assemble, and effectively protects the feedforward microphone 24 without affecting the headphone's appearance. The internal cavity of the housing 21 is designed as a spiral structure with frequency division and flow guiding effects. In open mode, it guides the diffusion of high-frequency sound waves, while in closed mode, it enhances low-frequency reflection.

[0031] This invention features a simple structure and high practicality. Through the synergy of an adjustable rear cavity and active noise cancellation (ANC technology), it resolves the inherent contradictions between open-back and closed-back headphones, combining a natural soundstage, powerful bass, and active noise cancellation capabilities. The valve opens or closes the tuning channel, enabling rapid switching between open-back (free airflow) and closed-back (completely sealed) modes. An open rear cavity allows free airflow, preventing sound waves from being completely reflected or absorbed, reducing resonance and standing wave interference. This results in a wider and more natural soundstage, stronger spatial awareness, clearer instrument positioning, and sound that doesn't feel muffled inside the earcups. Conversely, a completely sealed rear cavity results in sound waves being absorbed or isolated after multiple reflections within the cavity. This leads to a narrower soundstage, a focused sound, but a lack of spatial depth, and powerful bass.

[0032] While the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention should not be limited to the same structure and operation as described above and the accompanying drawings. For those skilled in the art, many equivalent improvements and variations can be made to the above embodiments through logical analysis, reasoning or limited experiments without exceeding the concept and scope of the present invention, but these improvements and variations should all fall within the scope of protection claimed by the present invention.

Claims

1. A kind of active noise reduction Bluetooth headset based on adjustable acoustic cavity back cavity, including head support (1) and two earphone main body (2) installed on head support (1), it is characterized in that: The headphone body (2) has a housing (21); the housing (21) has a cavity and a speaker (22) is provided in the cavity. The speaker divides the cavity into a front cavity (211) close to the user's ear and a rear cavity (212) away from the user's ear. The housing (21) has a tuning channel that connects to the rear cavity (212), a valve (23) for opening or closing the tuning channel, and a feedforward microphone (24) for capturing external ambient noise. A feedback microphone (25) for detecting residual noise that actually enters the ear is provided in the front cavity (211). The headphone body (2) also has a main control unit (3) for active noise reduction based on external ambient noise and residual noise that actually enters the ear.

2. The active noise reduction Bluetooth headset based on the adjustable sound cavity back cavity according to claim 1, characterized in that: The housing (21) is composed of an inner liner (213) and an outer shell (214), and the main control unit (3) is embedded between the inner liner (213) and the outer shell (214). The inner liner (213) has a cavity inside, and a first through hole (2131) connecting the rear cavity (212) is opened on the inner liner. A second through hole (2141) connecting the first through hole (2131) is opened on the outer shell (214). The first through hole (2131) and the second through hole (2141) are connected to form a tuning channel. The valve (23) opens or closes the tuning channel by opening or closing the relationship between the first through hole (2131) and the second through hole (2141).

3. The active noise reduction Bluetooth headset based on the adjustable sound cavity back cavity according to claim 1 or 2, characterized in that: The valve (23) includes a door panel (231) that is embedded between the first through hole (2131) and the second through hole (2141) and can slide, and an actuating member (232) that connects the door panel and extends out from the housing (21). The actuating member (232) moves back and forth along the pre-set guide groove (215) on the housing (21) and drives the door panel (231) to slide, so that the door panel (231) is inserted between the first through hole (2131) and the second through hole (2141) to cut off the connection between the first through hole (2131) and the second through hole (2141), or the door panel (231) is moved out from between the first through hole (2131) and the second through hole (2141) to open the connection between the first through hole (2131) and the second through hole (2141).

4. The active noise reduction Bluetooth headset based on the adjustable sound cavity back cavity according to claim 3, characterized in that: The valve (23) supports multi-stage switching modes.

5. The active noise reduction Bluetooth headset based on the adjustable sound cavity back cavity according to claim 1 or 2, characterized in that: The main control unit (3) includes an ANC circuit, and the active noise reduction of the main control unit includes: When the tuning channel is open, the rear cavity is in open mode, and the main control unit enhances low-frequency compensation and cancels low-frequency loss caused by sound leakage. When the tuning channel is closed, the rear cavity is in a sealed mode, and the main control unit increases the high-frequency noise reduction depth to suppress cavity resonance.

6. The active noise reduction Bluetooth headset based on the adjustable sound cavity back cavity according to claim 1, characterized in that: The feedforward microphone (24) is hidden inside the housing (21) and captures external ambient noise through a pre-set air hole (216) in the housing (21).

7. The active noise reduction Bluetooth headset based on the adjustable sound cavity back cavity according to claim 1, characterized in that: The cavity inside the housing (21) is designed as a spiral structure with frequency division and flow guiding function.

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