CN216528004U - Active noise eliminator - Google Patents

Abstract

The utility model discloses an active noise eliminator which comprises a driver, a box body, a sound net, a cavity, a first pickup module, an audio processor module and a power amplifier module, wherein the driver and the cavity are arranged in the box body, the front surface of the driver is hermetically connected with the cavity, the sound net is arranged on the box body, the sound net is arranged on the rear side of the driver, the first pickup module is arranged outside the box body, the first pickup module is electrically connected with the audio processor module, the audio processor module is electrically connected with the power amplifier module, and the power amplifier module is electrically connected with the driver. The utility model can achieve the purpose of eliminating low-frequency standing waves in a room, improve the reverberation in the room and greatly improve the recording quality of sound.

Description

Active noise eliminator

Technical Field

The utility model belongs to the technical field of noise elimination, and particularly relates to an active noise elimination device.

Background

Record the field in the tradition, in order to improve room standing wave, reverberation and reflection influence, the passive sound device of inhaling of commonly used is placed in four corners in room department, fills sound absorption material through the cavity and improves the low frequency and inhale the sound quality, reduces the influence of corner standing wave, and the surface passes through the arc angle and handles, enlarges the diffusion surface, but this kind of passive sound device of inhaling receives the low frequency wavelength influence, and is bulky, with high costs, and is unfavorable for portable transport.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide an active noise eliminator aiming at solving the problems in the background, which can achieve the aim of eliminating low-frequency standing waves in a room, improve the reverberation in the room and greatly improve the recording quality of sound.

In order to achieve the purpose, the utility model provides an active noise elimination device which comprises a driver, a box body, a sound net, a cavity, a first sound pickup module, an audio processor module and a power amplifier module, wherein the driver and the cavity are arranged in the box body, the front surface of the driver is hermetically connected with the cavity, the sound net is installed on the box body, the sound net is arranged on the rear side of the driver, the first sound pickup module is arranged outside the box body and electrically connected with the audio processor module, the audio processor module is electrically connected with the power amplifier module, and the power amplifier module is electrically connected with the driver.

Preferably, the device further comprises a current feedback module and a voltage feedback module, wherein the current feedback module and the voltage feedback module are respectively electrically connected with the driver, and the current feedback module and the voltage feedback module are respectively electrically connected with the audio processor module.

Preferably, the device further comprises a second pickup module, the second pickup module is arranged in the box body, and the second pickup module is electrically connected with the audio processor module.

Preferably, the first pickup module is provided with at least one pickup.

Preferably, at least one second pickup module is arranged.

Preferably, the device further comprises a third pickup module, the third pickup module is installed in the cavity, and the third pickup module is electrically connected with the audio processor module.

Preferably, the power amplifier module includes a gain module and a power module.

Preferably, the cavity is filled with a sound absorption material.

Preferably, the sound net has an opening size of 3mm by 0.2mm and an opening ratio of 5-8%.

Preferably, the device further comprises an LED module.

Compared with the prior art, the utility model has the beneficial effects that:

1. the first pickup module outside the sound net detects the sound pressure in a room, the acoustic characteristic impedance matching processing is carried out through the audio processor module, the sound pressure is restored through the power amplifier module, and the sound pressure is played through the driver, so that the aim of eliminating low-frequency standing waves in the room is fulfilled, the reverberation in the room is improved, and the sound recording quality is greatly improved.

2. The volume is small, the portability is strong, the cost is low, and the equivalent silencing area is large;

3. detecting the sound pressure restored by the driver through the second sound pickup module, comparing the sound pressure restored by the driver with the external sound pressure of the sound network, and controlling the output of the driver to form closed-loop detection;

4. set up a plurality of first pickup modules and second pickup module, can improve and detect the precision.

Drawings

FIG. 1 is a schematic structural view of the present invention;

fig. 2 is a schematic diagram of the module connection of the present invention.

In the drawings, the reference numbers: 1. a driver; 2. a box body; 3. an acoustic mesh; 4. a cavity; 5. a first pickup module; 6. a second pickup module; 7. an audio processor module; 8. a power amplifier module; 9. and (4) sound absorption materials.

Detailed Description

In order to make the technical solution of the present invention more apparent, the present invention is further described in detail with reference to the following examples, it should be understood that the specific embodiments described herein are only for explaining the present invention and are not to be construed as limiting the present invention.

Example one

Referring to fig. 1, an active muffler device includes a driver 1, a housing 2, a sound net 3, a cavity 4, a first sound pickup module 5, a second sound pickup module 6, an audio processor module 7, and a power amplifier module 8. The power amplifier module 8 comprises a gain module 801 and a power module 802.

The cavity 4 is arranged at the rightmost side in the box body 2, the front surface of the driver 1 is hermetically connected with the cavity 4, the driver 1 and the cavity 4 form a sealed area integrally, and sound waves played at the front surface of the driver 1 cannot be transmitted out of the cavity 4 because the inside of the cavity 4 is sealed.

Further, the cavity 4 described in this embodiment is filled with a sound-absorbing material 9. The sound absorption material 9 is mainly made of glass fiber cotton, rock wool, egg cotton, polyester fiber cotton and the like, and the sound absorption material 9 is mainly used for reducing the Q value of the resonant frequency after the driver 1 is acoustically coupled with the inside of the cavity 4. The lower the Q value is, the larger the low-frequency bandwidth range is, and the better the active sound absorption effect of the whole product in the low frequency range of 15 Hz-200 Hz is fed back.

The sound wave played by the front side of the driver 1 is absorbed by the sound absorption material 9 in the cavity 4 and cannot be transmitted out of the cavity 4.

The back of the driver 1 can radiate reverse sound wave with the same sound pressure as the forward sound pressure to be transmitted out of the box body 2 through the sound net 3.

The sound screen 3 is mounted on the left side of the cabinet 2. The first sound pickup module 5 is disposed outside the case 2, that is, outside the sound net 3. The second module is arranged in the cabinet 2, i.e. in the sound net 3.

A first sound pickup module 5, specifically a microphone, is used for detecting the external sound pressure of the sound net 3. When the first sound pickup module 5 senses that there is no signal or does not reach a set threshold, the apparatus of this embodiment is in a standby state, and when the external sound pressure of the sound network reaches the threshold, the apparatus starts to operate, and the first sound pickup module 5 transmits the detected signal to the audio processor 7 for processing, and then amplifies the signal to the driver 1 through the power amplifier module 8 for restoration. In this embodiment, the threshold is a sensitivity or a sound pressure value corresponding to a low frequency band of 15Hz to 200 Hz.

A second sound pickup module 6, specifically a microphone, is used to detect the sound pressure inside the sound net 3. The second pickup module 6 detects the sound pressure restored by the driver 1, transmits the detected signal to the MCU for judgment, when the sound pressure restored by the driver 1 is smaller than the external sound pressure of the sound network, the gain module 801 increases the output gain, the sound pressure is amplified by the power module 802 and then output by the driver 1, closed loop detection is formed, the sound pressure value restored by the driver 1 is always consistent with the external sound pressure value of the sound network, the phases are opposite, and a stable active sound absorption effect is achieved.

The first and second sound pickup modules 5 and 6 may be provided in more than one number, so as to improve the detection accuracy of the sound pressure restored by the driver 1, which is smaller than the sound pressure outside the sound network and the sound pressure restored by the driver 1, but accordingly, the product structure is more complicated and the cost is increased.

Referring to fig. 2, the first sound pickup module 5 and the second sound pickup module 6 are electrically connected to an audio processor module 7, the audio processor module 7 is electrically connected to a power amplifier module 8, and the power amplifier module 8 is electrically connected to the driver 1, respectively. The device of this embodiment still includes power module for the circuit power supply, MCU for circuit control and LED lamp module are used for when power module is closed, the device is at the beginning of the work, and luminous instructs.

The audio processor module 7 comprises a DSP processing part, and is used for filtering frequencies except 15 Hz-200 Hz and adjusting the gain value of the output level of the frequency band, so that the sensitivity of the device in the embodiment at the low frequency band of 15 Hz-200 Hz is improved.

In other embodiments, the second pickup module 6 may be replaced by a combination of a current feedback module and a voltage feedback module. The current feedback module and the voltage feedback module are respectively and electrically connected with the driver 1, and the current feedback module and the voltage feedback module are respectively and electrically connected with the audio processor module 7. The vibration signal of the driver 1 is detected through voltage feedback at two ends of a coil of the driver 1 and current feedback at two ends of the coil of the driver 1, and the MCU controls the output of the driver 1 by comparing external sound pressure of an acoustic network with the vibration signal of the driver 1. However, the detection accuracy of this scheme is lowered, and the active sound absorption effect is inferior to that of the present embodiment.

In other embodiments, the apparatus may further comprise a third sound pickup module, in particular a microphone. The third pickup module is arranged in the cavity 4 and is electrically connected with the audio processor module 8. The third pickup module is used for detecting the sound pressure in the cavity, so that the sound pressure in the cavity 4 is adjusted.

The inside of the cavity 4 is a pressure field, the outside of the cavity 4 (namely the inside and the outside of the sound net) is a free field, the two feedback principles are different, and a third sound pickup module is not recommended. Since the pressure in the cavity 4 is very high when the driver 1 vibrates, the capacitive diaphragms are easily damaged. In addition, the active damping on the sound screen 3 is regulated by the free field and cannot be realized by the pressure field.

According to the sound wave vertical incidence model, when two different media exist, as long as the fluid characteristic impedance of the two media is equal, the interface between the media is as if the interface does not exist for sound propagation, and the sound wave is not transmitted and is totally transmitted as if the sound wave enters a black hole for absorption.

In order to keep the internal and external characteristic impedance of the sound net 3 consistent, the aperture ratio and the aperture size of the sound net 3 need to have certain air flow resistance characteristic, and the characteristic can enlarge the sound pressure on the surface of the driver 1 into the sound pressure inside the whole sound net 3, namely, the sound absorption area is far larger than the sound pressure on the surface of the driver 1, so that the characteristic of large indoor sound absorption area is achieved, and the sound absorption area is spherical wave dispersion.

In the present embodiment, the acoustic mesh 3 needs to satisfy the air flow resistance characteristic of 100Pa · s/m, the size of the acoustic mesh is referred to as 3 × 0.2mm, and the aperture ratio is referred to as 5% to 8%. The air flow resistance characteristic of each sound mesh is the same, and the sound pressure inside the sound mesh 3 is evenly distributed.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (10)

1. The utility model provides an initiative noise eliminator, its characterized in that, includes driver, box, sound net, die cavity, first pickup module, audio processor module and power amplifier module, the driver with the die cavity sets up in the box, the front of driver with die cavity sealing connection, the sound net install in on the box, the sound net set up in the rear side of driver, first pickup module set up in outside the box, first pickup module with audio processor module electricity is connected, audio processor module with power amplifier module electricity is connected, power amplifier module with the driver electricity is connected.

2. The active muffler device according to claim 1, further comprising a current feedback module and a voltage feedback module, wherein the current feedback module and the voltage feedback module are electrically connected to the driver, respectively, and the current feedback module and the voltage feedback module are electrically connected to the audio processor module, respectively.

3. The active muffler device according to claim 1, further comprising a second sound pickup module disposed in the case, the second sound pickup module being electrically connected to the audio processor module.

4. The active muffler device of claim 1, wherein the first pickup module is provided with at least one.

5. The active muffler device of claim 3, wherein the second pickup module is provided with at least one.

6. The active muffler device of claim 1, further comprising a third pickup module mounted within the cavity, the third pickup module electrically connected to the audio processor module.

7. The active muffler device of claim 1, wherein the power amplifier module comprises a gain module and a power module.

8. The active muffler device of claim 1, wherein the cavity is filled with a sound absorbing material.

9. The active muffler device of claim 1, wherein the acoustic mesh has an opening size of 3mm by 0.2mm and an opening ratio of 5 to 8%.

10. The active muffler device of claim 1, further comprising an LED module.

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