Acoustic filter

Abstract

This utility model discloses an acoustic filter, including a circuit board, a lower cover fixed to the top of the circuit board, and an upper cover fixed to the top surface of the lower cover. A filter turntable is rotatably mounted inside the lower cover, and a circular notch corresponding to the filter turntable is opened on the top surface of the upper cover. The filter turntable integrates a reverberation filter, a high-frequency filter, and a low-frequency filter. Three metal spring switches are provided on the circuit board. This acoustic filter, through innovative structural design and functional integration, achieves integrated and efficient acoustic filtering functions for multiple scenarios. Its core lies in the use of a rotatable turntable that integrates low-frequency, high-frequency, and reverberation filters, allowing for rapid switching of filtering modes through simple rotation. More importantly, the device achieves a highly efficient operation mode of "rotation switching equals gain linkage" through a mechanically triggered hardware-level circuit compensation mechanism, ensuring precise synchronization between filtering effect and gain compensation.

Description

Technical Field

[0001] This utility model belongs to the field of acoustic filtering technology, and specifically relates to an acoustic filter. Background Technology

[0002] In acoustic processing scenarios, the filtering requirements for audio signals are highly diverse. The filtering requirements for audio signals vary in different application scenarios. For example, in a recording studio environment, it is necessary to effectively filter out low-frequency noise to improve recording quality; while in a conference or lecture setting, it is necessary to attenuate high-frequency noise to reduce background interference; in addition, in spaces such as theaters or concert halls, reducing the impact of reverberation is crucial to ensuring sound clarity and positioning accuracy.

[0003] However, most existing acoustic filtering devices only have a single filter function, which is difficult to meet the filtering needs of diverse scenarios. When it is necessary to switch filtering modes, the operation process is complicated and time-consuming, often requiring manual replacement of filters or adjustment of complex parameter settings. More importantly, these devices are difficult to achieve precise linkage between filtering effect and gain compensation during the switching of filtering modes, resulting in signal distortion or gain imbalance during signal processing. Especially in small acoustic devices, such as headphones and microphones, existing filtering devices are often difficult to adapt due to their large size and complex structure, and their stability and ease of operation are significantly insufficient, failing to meet the needs of efficient and portable acoustic processing.

[0004] To address the aforementioned issues, there is an urgent need in the market for an acoustic filter device that can flexibly switch filtering modes and achieve precise linkage between filtering and gain compensation. Utility Model Content

[0005] The purpose of this invention is to provide an acoustic filter to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: an acoustic filter, comprising...

[0007] Circuit board, lower cover fixed to the top of the circuit board, upper cover fixed to the top surface of the lower cover;

[0008] The lower cover is rotatably fitted with a filter turntable, and the top surface of the upper cover has a circular notch corresponding to the filter turntable. The filter turntable integrates a reverberation filter, a high-frequency filter, and a low-frequency filter.

[0009] The circuit board is provided with three metal spring switches, each including an upper spring and a lower spring. The free ends of the upper and lower springs extend through the inside of the lower cover and are located at the bottom of the filter turntable. The bottom surface of the filter turntable is provided with a metal contact protrusion corresponding to the metal spring switch. The side of the lower cover is provided with a turntable notch corresponding to the filter turntable, and the edge of the filter turntable extends to the outside of the lower cover through the turntable notch.

[0010] The circuit board is equipped with three parallel compensation circuits, which correspond one-to-one with three metal spring switches and filters.

[0011] Preferably, the filter turntable has three circular mounting holes on its surface for mounting a reverberation filter, a high-frequency filter, and a low-frequency filter. The low-frequency filter consists of a fixing ring three, a plastic collar, and high-density foam. The high-density foam fills the inside of the plastic collar, and the plastic collar is fixed in one of the circular mounting holes on the surface of the filter turntable by the fixing ring three. The high-frequency filter consists of a fixing ring two, a polytetrafluoroethylene film, and a stainless steel mesh. The polytetrafluoroethylene film and the stainless steel mesh are ultrasonically welded together and are interference-fitted with one of the circular mounting holes on the surface of the filter turntable by the fixing ring two. The reverberation filter consists of a fixing ring one and a porous ceramic. The porous ceramic is embedded in one of the circular mounting holes on the surface of the filter turntable by the fixing ring one.

[0012] Preferably, the metal spring switch includes an upper spring and a lower spring, with the upper spring located directly above the lower spring.

[0013] Preferably, both the upper and lower springs are made of phosphor bronze, and the lower surface of the free end of the upper spring and the upper surface of the free end of the lower spring are provided with silver-plated conductive contacts.

[0014] Preferably, a base shaft is fixed on the inner side of the lower cover, and the filter turntable is rotatably sleeved on the base shaft. A positioning gear mechanism is also provided between the lower cover and the filter turntable.

[0015] Preferably, the positioning gear mechanism includes an L-shaped swing block, a reset spring, a swing shaft, and a circular positioning side. The swing shaft is fixed to the inner side of the lower cover. The L-shaped swing block is rotatably mounted on the inner side of the lower cover and located at the bottom of the filter turntable via the swing shaft. The reset spring is installed between the rear end of the L-shaped swing block and the inner wall of the lower cover. The circular positioning side is fixed at the bottom center of the filter turntable, and the front end of the L-shaped swing block is engaged in one of the tooth grooves of the circular positioning side.

[0016] Preferably, screw holes are provided at all four corners of the upper cover, and threaded grooves corresponding to the screw holes are provided at all four corners of the top surface of the lower cover.

[0017] Preferably, an auxiliary structure is provided between the upper cover and the lower cover. The auxiliary structure includes two positioning strips fixed to the bottom surface of the upper cover. Both positioning strips are inserted into the inner side of the lower cover and respectively fit against the inner walls on both sides of the lower cover. The outer surface of the positioning strip is provided with an integral hemispherical positioning protrusion. The inner walls on both sides of the lower cover are provided with circular positioning sides for the hemispherical positioning protrusion to be inserted.

[0018] Compared with existing technologies, the beneficial effects of this utility model are as follows: This utility model proposes a switchable acoustic filter, which achieves integrated and efficient acoustic filtering functions for multiple scenarios through innovative structural design and functional integration. Its core lies in the use of a rotatable turntable that integrates low-frequency, high-frequency, and reverberation filters, allowing for rapid switching of filtering modes through simple rotation. More importantly, the device achieves a highly efficient operation mode of "rotation switching equals gain linkage" through a mechanically triggered hardware-level circuit compensation mechanism, ensuring precise synchronization between filtering effect and gain compensation. The precise cooperation between the metal contact protrusions and the phosphor bronze spring switch not only provides fast response and strong anti-interference capabilities but also ensures the stability and reliability of the device during long-term use, with an extremely low failure rate. Simultaneously, the three differentiated compensation circuits are optimized for the characteristics of different filters, significantly improving the clarity and integrity of the filtered signal, providing a reliable acoustic processing solution for small acoustic devices such as headphones and microphones, and meeting the needs for high efficiency and portability in diverse scenarios. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of this utility model;

[0020] Figure 2 This is an exploded view of the filter turntable and filter assembly of this utility model.

[0021] Figure 3 This is an exploded view of the present invention;

[0022] Figure 4 This is a top view of the internal structure of the lower cover of this utility model;

[0023] Figure 5 This is a bottom view of the filter turntable and positioning gear mechanism of this utility model;

[0024] Figure 6 This is a perspective view of the internal structure of the lower cover of this utility model;

[0025] Figure 7 This is a circuit diagram of the three-way compensation circuit and the filter linkage circuit of this utility model;

[0026] Figure 8 This is a cross-sectional view of the auxiliary structure of this utility model;

[0027] In the diagram: 1. Circuit board; 2. Upper spring; 3. Lower spring; 4. Top cover; 41. Positioning insert; 42. Hemispherical positioning protrusion; 5. Filter turntable; 6. Reverb filter; 61. Fixing ring one; 62. Porous ceramic; 7. High-frequency filter; 71. Fixing ring two; 72. PTFE film; 73. Stainless steel mesh; 8. Low-frequency filter; 81. Fixing ring three; 82. Plastic collar; 83. High-density foam; 9. Bottom cover; 91. L-shaped swing block; 92. Reset spring; 93. Swing shaft; 94. Turntable notch; 95. Circular positioning side; 10. Metal contact protrusion. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model. Example 1

[0029] Please see Figures 1 to 7 This is the first embodiment of the present invention, which provides the following technical solution: an acoustic filter, comprising...

[0030] Circuit board 1, lower cover 9 fixed to the top of circuit board 1, upper cover 4 fixed to the top surface of lower cover 9;

[0031] The lower cover 9 is fitted with a rotating filter disc 5, and the top surface of the upper cover 4 has a circular notch corresponding to the filter disc 5. The filter disc 5 integrates a reverberation filter 6, a high-frequency filter 7, and a low-frequency filter 8. The diameter of the filter disc 5 is 1cm, which is within the range of small devices.

[0032] The circuit board 1 is equipped with three metal spring switches, each including an upper spring 2 and a lower spring 3. The free ends of the upper spring 2 and the lower spring 3 extend through the inside of the lower cover 9 and are located at the bottom of the filter turntable 5. The bottom surface of the filter turntable 5 is provided with a metal contact protrusion 10 corresponding to the metal spring switch. The side of the lower cover 9 is provided with a turntable notch 94 corresponding to the filter turntable 5, and the edge of the filter turntable 5 extends to the outside of the lower cover 9 through the turntable notch 94. The edge of the filter turntable 5 can be moved to make the filter turntable 5 start to rotate, thereby rotating the metal contact protrusion 10 to contact the corresponding metal spring switch, realizing the closure of the corresponding metal spring switch, triggering the connection of the preset resistor-capacitor network in the circuit board 1, and realizing the linkage of filtering and circuit compensation.

[0033] Circuit board 1 has three parallel compensation circuits, corresponding one-to-one with three metal spring switches and filters. The low-frequency filter 8 circuit consists of switch S1, small resistor R1, and capacitor C1 connected in series. After filtering, it enhances the 300-800Hz low-frequency signal through an RC network, and can compensate for the gain of mid-to-high frequency signals, offsetting the attenuation of the high-frequency filter in this frequency band. The high-frequency filter 7 circuit consists of switch S2, large resistor R2, and inductor L1 connected in series. After filtering, it enhances the 1000-3000Hz high-frequency signal through an RL network. It uses the impedance characteristic of inductance to enhance the gain of low-frequency signals and compensate for the loss of low-frequency filter in this frequency band. The reverberation filter 6 circuit consists of switch S3 and fixed resistor R3 connected in series. It constructs a negative feedback loop through stable impedance matching to maintain a balanced gain of the signal across the entire frequency band, ensuring that the signal is not distorted after reverberation processing.

[0034] In this embodiment, preferably, the surface of the filter turntable 5 has three circular mounting holes for mounting the reverberation filter 6, the high-frequency filter 7, and the low-frequency filter 8. The low-frequency filter 8 consists of a fixing ring 81, a plastic collar 82, and high-density foam 83. The high-density foam 83 fills the inside of the plastic collar 82 to ensure the stability of the foam shape. The porous structure of the foam can effectively absorb low-frequency noise. The plastic collar 82 is fixed in one of the circular mounting holes on the surface of the filter turntable 5 by the fixing ring 81. The high-frequency filter 7 consists of a fixing ring 71, a polytetrafluoroethylene film 72, and a stainless steel mesh 73. The polytetrafluoroethylene film 72 and the stainless steel mesh 73 are ultrasonically welded together to avoid separation of the two materials. The reverberation filter has a good filtering effect and can attenuate high-frequency noise. The thin film material further improves corrosion resistance and signal transmittance. The stainless steel mesh 73 is interference-fitted with one of the circular mounting holes on the surface of the filter turntable 5 through the fixing ring 2 71 to prevent structural loosening due to vibration during high-frequency filtering. The reverberation filter 6 is composed of fixing ring 1 61 and porous ceramic 62. The porous ceramic 62 is embedded in one of the circular mounting holes on the surface of the filter turntable 5 through fixing ring 1 61 to ensure uniform stress on the ceramic structure and reduce the risk of breakage. The honeycomb structure of the porous ceramic 62 can reduce reverberation by scattering sound waves. A small amount of adhesive can be applied to the fixing ring 1 61 during assembly to help fix it and ensure that it will not loosen during long-term use.

[0035] In this embodiment, preferably, the metal spring switch includes an upper spring 2 and a lower spring 3, with the upper spring 2 located directly above the lower spring 3.

[0036] In this embodiment, preferably, both the upper spring 2 and the lower spring 3 are made of phosphor bronze, which has good elasticity and conductivity, ensuring reliable contact after repeated triggering. Furthermore, the lower surface of the free end of the upper spring 2 and the upper surface of the free end of the lower spring 3 are provided with silver-plated conductive contacts to reduce contact resistance and improve signal transmission efficiency. Subsequently, when the filter turntable 5 is rotated to align the target filter with the pickup position, the metal contact protrusion 10 at its bottom will press the corresponding metal spring switch to close. Initially, the filter turntable 5 is not rotated, all three metal spring switches are in the open state, the upper spring 2 and lower spring 3 maintain a distance, the three compensation circuits are in a high-impedance state, and the device has no filtering or compensation function. When it is necessary to switch to the low-frequency filter 8 mode, the filter turntable 5 is manually rotated to align the low-frequency filter 8 with the pickup port. The metal contact protrusion 10 rotates with the filter turntable 5 to above the first metal spring switch, and its bottom plane presses down on the upper spring 2, causing the upper spring 2 and lower spring 3 to... When contact point 3 is activated, the corresponding switch closes, the low-frequency filter 8 circuit is turned on, and the RC network operates to achieve gain compensation for mid-to-high frequency signals. When switching to the high-frequency filter 7 mode, rotating filter dial 5 aligns the high-frequency filter 7 with the pickup port. The metal contact protrusion 10 presses down on the second metal spring switch, triggering the metal spring switch to close, turning on the high-frequency filter 7 circuit, and the RL network enhances the gain of the low-frequency signal. When switching to the reverb filter 6 mode, rotating filter dial 5 aligns the reverb filter 6 with the pickup port. The metal contact protrusion 10 presses down on the third metal spring switch, triggering the corresponding switch to close, turning on the reverb filter 6 circuit, and achieving balanced gain across the entire frequency band through stable impedance. When filter dial 5 is rotated again, the previously triggered metal contact protrusion 10 leaves the spring, the upper spring 2 resets under its own elasticity, the corresponding circuit is disconnected, and the triggering process of the new target filter repeats the above logic, achieving uninterrupted mode switching.

[0037] In this embodiment, preferably, a base shaft is fixed on the inner side of the lower cover 9, and the filter turntable 5 is rotatably sleeved on the base shaft, so that the filter turntable 5 can rotate smoothly. A positioning gear mechanism is also provided between the lower cover 9 and the filter turntable 5.

[0038] In this embodiment, preferably, the positioning gear mechanism includes an L-shaped swing block 91, a reset spring 92, a swing shaft 93, and a circular positioning side 95. The swing shaft 93 is installed inside the lower cover 9. The L-shaped swing block 91 is rotatably installed inside the lower cover 9 via the swing shaft 93 and is located at the bottom of the filter turntable 5. The reset spring 92 is installed between the rear end of the L-shaped swing block 91 and the inner wall of the lower cover 9. The circular positioning side 95 is fixed at the bottom center of the filter turntable 5, and the front end of the L-shaped swing block 91 is engaged in one of the tooth grooves of the circular positioning side 95. When the filter turntable 5 is rotated, the circular positioning side 95 will also rotate and squeeze the front end of the L-shaped swing block 91, causing the L-shaped swing block 91 to rotate and stretch the reset spring 92. Then, as the filter turntable 5 continues to rotate, the front end of the L-shaped swing block 91 will engage in other tooth grooves of the circular positioning side 95, thereby forming clear positioning feedback during the rotation of the filter turntable 5 and avoiding misoperation.

[0039] In this embodiment, preferably, screw holes are provided at all four corners of the upper cover 4, and threaded grooves corresponding to the screw holes are provided at all four corners of the top surface of the lower cover 9, so that the upper cover 4 can be easily fixed to the top of the lower cover 9 by screws.

[0040] In summary, this acoustic filter integrates and quickly switches between filtering functions for multiple scenarios. Through hardware-level linkage of mechanical triggering and circuit compensation, it improves ease of operation, structural stability, and signal processing accuracy, making it suitable for small acoustic devices such as headphones and microphones. Example 2

[0041] Please see Figures 1 to 8 This is the second embodiment of the present invention. Based on the previous embodiment, the difference is that an auxiliary structure is provided between the upper cover 4 and the lower cover 9. The auxiliary structure includes two positioning strips 41 fixed to the bottom surface of the upper cover 4. Both positioning strips 41 are inserted into the inner side of the lower cover 9 and respectively fit against the inner walls of both sides of the lower cover 9. The outer surface of the positioning strips 41 is provided with an integral hemispherical positioning protrusion 42. Both are made of rubber and will undergo elastic deformation when compressed. The inner walls of both sides of the lower cover 9 are provided with circular positioning sides 95 for the hemispherical positioning protrusions 42 to be inserted into, so that… When the upper cover 4 is connected to the lower cover 9, the operator can place the upper cover 4 on top of the lower cover 9, so that the positioning strip 41 is inserted into the inside of the lower cover 9, and the hemispherical positioning protrusion 42 is squeezed and elastically deformed and squeezed into the circular positioning side 95, thus achieving auxiliary limiting of the upper cover 4 at this time, ensuring that the upper cover 4 will not easily slip during the installation process, and ensuring that the screw holes on the upper cover 4 are continuously aligned with the threaded grooves on the lower cover 9 during the installation process, which facilitates the operator to install the screws. The auxiliary structure here plays an auxiliary limiting role when the upper cover 4 is installed, further improving the ease of installation.

[0042] Although embodiments of the present invention have been shown and described (see the detailed description above), it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An acoustic filter, characterized by: include Circuit board (1), lower cover (9) fixed on the top of circuit board (1), upper cover (4) fixed on the top surface of lower cover (9); The lower cover (9) is rotatably fitted with a filter turntable (5), and the top surface of the upper cover (4) is provided with a circular notch corresponding to the filter turntable (5). The filter turntable (5) integrates a reverberation filter (6), a high-frequency filter (7) and a low-frequency filter (8). The circuit board (1) is provided with three metal spring switches, each of which includes an upper spring (2) and a lower spring (3). The free ends of the upper spring (2) and the lower spring (3) extend through the inner side of the lower cover (9) and are located at the bottom of the filter turntable (5). The bottom surface of the filter turntable (5) is provided with a metal contact protrusion (10) corresponding to the metal spring switch. The side of the lower cover (9) is provided with a turntable notch (94) corresponding to the filter turntable (5), and the edge of the filter turntable (5) extends to the outside of the lower cover (9) through the turntable notch (94). The circuit board (1) is provided with three parallel compensation circuits, which correspond one-to-one with three metal spring switches and filters.

2. An acoustic filter according to claim 1, characterized in that: The filter turntable (5) has three circular mounting holes on its surface for mounting a reverberation filter (6), a high-frequency filter (7), and a low-frequency filter (8). The low-frequency filter (8) consists of a fixing ring three (81), a plastic collar (82), and high-density foam (83). The high-density foam (83) fills the inside of the plastic collar (82), and the plastic collar (82) is fixed in one of the circular mounting holes on the surface of the filter turntable (5) by the fixing ring three (81). The high-frequency filter (7) consists of a fixing ring two (81), a high-frequency filter (82), and a high-density foam (83). 71) The filter (6) is composed of a polytetrafluoroethylene film (72) and a stainless steel mesh (73). The polytetrafluoroethylene film (72) and the stainless steel mesh (73) are ultrasonically welded together and are interference-fitted with one of the circular mounting holes on the surface of the filter turntable (5) through a fixing ring two (71). The reverberation filter (6) is composed of a fixing ring one (61) and a porous ceramic (62). The porous ceramic (62) is embedded in one of the circular mounting holes on the surface of the filter turntable (5) through the fixing ring one (61).

3. An acoustic filter according to claim 1, characterized in that: The metal spring switch includes an upper spring (2) and a lower spring (3), with the upper spring (2) located directly above the lower spring (3).

4. An acoustic filter according to claim 3, characterized in that: Both the upper spring (2) and the lower spring (3) are made of phosphor bronze, and the lower surface of the free end of the upper spring (2) and the upper surface of the free end of the lower spring (3) are provided with silver-plated conductive contacts.

5. An acoustic filter according to claim 1, characterized in that: A base shaft is fixed on the inner side of the lower cover (9), and the filter turntable (5) is rotatably mounted on the base shaft. A positioning gear mechanism is also provided between the lower cover (9) and the filter turntable (5).

6. An acoustic filter according to claim 5, characterized in that: The positioning gear mechanism includes an L-shaped swing block (91), a reset spring (92), a swing shaft (93), and a circular positioning side (95). The swing shaft (93) is fixed to the inner side of the lower cover (9). The L-shaped swing block (91) is rotatably mounted on the inner side of the lower cover (9) and located at the bottom of the filter turntable (5) via the swing shaft (93). The reset spring (92) is installed between the rear end of the L-shaped swing block (91) and the inner wall of the lower cover (9). The circular positioning side (95) is fixed at the bottom center of the filter turntable (5), and the front end of the L-shaped swing block (91) is engaged in one of the tooth grooves of the circular positioning side (95).

7. An acoustic lens according to claim 1, wherein: The upper cover (4) has screw holes at all four corners, and the lower cover (9) has threaded grooves at all four corners of its top surface that correspond to the screw holes.

8. An acoustic lens according to claim 1, wherein: An auxiliary structure is provided between the upper cover (4) and the lower cover (9). The auxiliary structure includes two positioning strips (41) fixed to the bottom surface of the upper cover (4). Both positioning strips (41) are inserted into the inner side of the lower cover (9) and respectively fit against the inner walls of the two sides of the lower cover (9). The outer surface of the positioning strip (41) is provided with an integral hemispherical positioning protrusion (42). The inner walls of both sides of the lower cover (9) are provided with circular positioning sides (95) for the hemispherical positioning protrusion (42) to be inserted.

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