A directional sound system with active noise reduction function and a control method

Abstract

This invention discloses a directional audio system and control method with active noise cancellation, comprising: a housing, a directional sound wave transmitter, an ambient noise pickup unit, an error microphone array, an active noise cancellation speaker group, a control circuit board, an active noise cancellation module, and a collaborative control module. This invention relates to the field of acoustic equipment technology. By integrating the directional sound wave transmitter, the active noise cancellation speaker group, and the error microphone array on the front surface of the housing, and with the active noise cancellation speaker and error microphone distributed around the directional sound wave transmitter, the dual functions of directional sound projection and active ambient noise cancellation are achieved. Users can obtain clear directional sound without wearing headphones, while ambient noise is actively eliminated, truly realizing a clear, undisturbed, and noise-free immersive personal audio experience. This technical solution fills a gap in the prior art and solves the long-standing dilemma of uncomfortable headphone use versus disturbing external speakers that has plagued those skilled in the art.

Description

Technical Field

[0001] This invention relates to the field of acoustic equipment technology, specifically to a directional sound system and control method with active noise reduction function. Background Technology

[0002] With the rapid development of mobile internet and streaming media technology, people's demand for personal audio experiences is constantly increasing. A search reveals that there is currently no integrated device that can both direct sound to the user's ears and actively eliminate ambient noise without the need for headphones. The main technical challenges lie in the following three aspects: 1. Sound field coupling and interference problem: The audible sound beam generated by the directional sound wave transmitter and the anti-phase sound wave generated by the active noise-canceling loudspeaker coexist in space. Both are audible sound waves. If left uncontrolled, the anti-phase sound wave may interfere with the normal propagation of the directional sound beam, causing sound quality degradation, sound field distortion, or even howling. 2. Spatial coordination and area matching issues: Directional sound beams have narrow beam characteristics, and their effective listening area is usually a small spatial range; while active noise cancellation needs to form an anti-phase sound field near the user's ear that matches the noise wavefront, and its effective noise cancellation area is usually also a finite spatial area. It is easy for the effective noise cancellation area and the listening area to not coincide precisely, and the state needs to be adjusted at any time as the user's head moves, resulting in ineffective noise cancellation. 3. Feedback stability and system integration issues: Active noise cancellation systems require error microphones to be placed in the noise reduction target area to collect residual noise as feedback signals. However, when the error microphone is close to the directional sound wave transmitter, the directional sound beam itself may be picked up by the microphone and misjudged as residual noise, causing the active noise cancellation system to generate incorrect control signals. Therefore, how to organically integrate directional sound technology with active noise cancellation technology to achieve an acoustic experience of "clear hearing for the listener, no disturbance to bystanders, and a quiet environment" is a technical problem that urgently needs to be solved in this field, and it is also the core technical challenge that this invention aims to overcome. Summary of the Invention

[0003] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a directional sound system and control method with active noise cancellation, aiming to solve the following technical problems: This invention achieves the technical effect of projecting sound directionally to the user's ears and actively eliminating ambient noise without wearing headphones, while ensuring both superior sound quality and noise reduction effect through coordinated control.

[0004] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: This invention provides a directional sound system with active noise cancellation, comprising: The housing has an internal cavity for accommodating the control circuit board and other electronic components, and the front end of the housing is an acoustic output surface. A directional acoustic wave transmitter is disposed on the front end face of the housing and is used to emit a directional audible sound beam toward a target area. The directional acoustic wave transmitter is preferably a piezoelectric ultrasonic transducer array, which uses the nonlinear self-demodulation effect of ultrasonic waves to generate audible sound. The array elements of the ultrasonic transducer array can be arranged in a ring, rectangle or hexagon. The spacing between the array elements is designed according to the working wavelength, usually between half a wavelength and one wavelength, to ensure the directionality of the emitted beam. An ambient noise pickup unit includes at least one reference microphone for acquiring ambient noise signals. The reference microphone is preferably located on the back or side of the housing to avoid directly picking up the sound played by a directional sound wave transmitter or an active noise-canceling speaker, thus ensuring that the reference signal is pure ambient noise. An error microphone array is disposed on the front end of the housing and surrounds the directional acoustic wave transmitter. It is used to collect residual noise signals in the target area. The error microphone array consists of multiple MEMS microphones that are evenly distributed in the circumferential direction. Its function is to pick up the residual noise signals after active noise reduction and use them as the error input of the FxLMS adaptive filtering algorithm. An active noise-canceling speaker group is disposed on the front end face of the housing and distributed around the directional sound wave transmitter to generate noise-canceling anti-phase sound waves. The active noise-canceling speaker group consists of multiple miniature motorized speakers, the number of which corresponds to the number of error microphones or is set independently. They are evenly distributed around the directional sound wave transmitter to ensure that the anti-phase sound waves can evenly cover the target noise-canceling area. A control circuit board, disposed inside the housing, includes: The directional sound drive module is used to generate an ultrasonic carrier and modulate an audible sound signal onto the carrier, which is then amplified to drive the directional sound wave transmitter. The active noise cancellation module is used to generate an inverse noise signal based on the ambient noise signal collected by the reference microphone and the residual noise signal collected by the error microphone array, and then drive the active noise cancellation speaker group. The collaborative control module is used to adjust the spatial superposition relationship between the directional sound beam and the noise reduction zone to avoid mutual interference between the two, and to dynamically adjust the direction of the sound beam and the position of the noise reduction zone according to changes in the user's position.

[0005] In some embodiments, the directional acoustic wave transmitter is a piezoelectric ultrasonic transducer array, with its array elements arranged in a ring or rectangle; the active noise-canceling loudspeaker group consists of multiple miniature electrodynamic loudspeakers, evenly distributed around the directional acoustic wave transmitter, with the array element arrangement matching the loudspeaker distribution position to ensure the symmetry and uniformity of the sound field.

[0006] In some embodiments, the error microphone array is located on the periphery of the active noise cancellation speaker group, and each error microphone is equidistant from the adjacent active noise cancellation speaker. This layout allows each error microphone to effectively pick up the superposition signal of the antiphase sound wave and residual noise generated by the corresponding active noise cancellation speaker, which is beneficial to the convergence of the adaptive filtering algorithm.

[0007] In some embodiments, the front end face of the housing is provided with an adjustable acoustic lens, which is made of a material with gradually varying acoustic impedance and is used to adjust the matching degree between the focusing position of the directional sound beam and the noise reduction area. The acoustic lens can be made of 3D printed phononic crystal material. By changing the geometry of the lens or the effective refractive index distribution, the axial movement of the sound beam focus can be achieved, thereby adapting to the needs of different listening distances.

[0008] In some embodiments, an attitude sensor is provided inside the housing. The attitude sensor is used to detect the pointing angle of the housing. The attitude sensor is preferably a six-axis inertial measurement unit, including a three-axis accelerometer and a three-axis gyroscope, which can detect the attitude angle of the housing in three-dimensional space in real time. The cooperative control module adjusts the emission direction of the directional sound beam according to the attitude signal.

[0009] In some embodiments, the collaborative control module, based on the attitude signal and a preset user ear position, adjusts the phase delay of the directional sound wave transmitter or drives a mechanical rotation mechanism to make the directional sound beam dynamically track the user's head movement and make the noise reduction zone follow the focal point of the directional sound beam. Specifically, when the user's head rotation is detected, the collaborative control module calculates the angle that the sound beam needs to be deflected and achieves electronic beam scanning by adjusting the phase delay of each element of the ultrasonic transducer array; or it achieves mechanical pointing adjustment by driving a micro motor to rotate the directional sound wave transmitter as a whole.

[0010] In some embodiments, a user position detection unit is also included. The user position detection unit is at least one of a camera, an infrared sensor, or an ultra-wideband positioning module, used to obtain the spatial position of the user's ear relative to the shell. The user position detection unit works in conjunction with the attitude sensor to achieve three-dimensional positioning of the user's head position and provide accurate target coordinates for sound beam pointing control.

[0011] In some embodiments, the control circuit board further includes a volume adaptive adjustment module, which is used to analyze the sound pressure level near the user's ear based on the residual noise signal collected by the error microphone array, and automatically adjust the volume of the directional sound beam. When the ambient noise increases, the volume adaptive adjustment module automatically increases the volume of the directional sound beam; when the ambient noise decreases, it automatically decreases the volume, so that the user always obtains a constant signal-to-noise ratio and a comfortable listening experience.

[0012] In some embodiments, the directional sound driving module employs a double-sideband modulation (BSB) or single-sideband modulation (SSB) algorithm to modulate the audible sound signal onto an ultrasonic carrier. BSB modulation is simple to implement but has low efficiency, while SSB modulation is more efficient and avoids carrier waste. The choice can be made according to the application scenario. The active noise reduction module employs a feedforward, feedback, or hybrid active noise reduction architecture and an adaptive filtering algorithm. This algorithm can track noise changes in real time and adaptively adjust the filtering coefficients, exhibiting good convergence performance and stability.

[0013] Secondly, the present invention provides a control method for a directional sound system with active noise cancellation function, applied to any of the above-mentioned directional sound systems with active noise cancellation function, comprising the following steps: S1: Emits a directional audible sound beam toward the target area via a directional sound wave transmitter; S2: Acquire ambient noise signals through a reference microphone and acquire residual noise signals within the target area through an error microphone array; S3: The active noise reduction module generates an inverse noise signal based on the ambient noise signal and the residual noise signal; S4: Play the inverse noise signal through an active noise-canceling speaker array to form a noise reduction zone in the target area; S5: The spatial overlap between the directional sound beam and the noise reduction zone is monitored in real time by the collaborative control module. When the overlap exceeds the set threshold, the driving parameters of the directional sound wave transmitter or the filtering coefficient of the active noise reduction module are adjusted to make the two staggered in space or frequency domain to avoid mutual interference.

[0014] In some embodiments, the method further includes: detecting the pointing angle of the housing by an attitude sensor, and automatically calculating the optimal emission direction of the directional sound beam based on a preset user ear position or a real-time position obtained by a user position detection unit; adjusting the phase delay of the directional sound wave transmitter or driving a mechanical rotation mechanism to make the sound beam dynamically track the user's head movement, and making the noise reduction zone follow the focal point of the directional sound beam.

[0015] In some embodiments, the method further includes: analyzing the sound pressure level near the user's ear using signals acquired by an error microphone array, automatically adjusting the volume of the directional sound beam to maintain a constant loudness in the listening area while maintaining noise reduction.

[0016] (III) Beneficial Effects Compared with the prior art, the present invention has the following beneficial effects: 1. Integrated personal audio space and noise cancellation This invention is the first to integrate directional sound technology and active noise cancellation technology into the same device. By integrating a directional sound wave emitter, an active noise cancellation speaker group, and an error microphone array on the front surface of the housing, and with the active noise cancellation speaker and error microphone distributed around the directional sound wave emitter, the dual functions of directional sound projection and active cancellation of environmental noise are achieved. Users can obtain clear directional sound without wearing headphones, while the surrounding environmental noise is actively eliminated, truly realizing an immersive personal audio experience that is clear, unobtrusive, and noise-free. This technical solution fills the gap in the existing technology and solves the dilemma that has long troubled those skilled in the art of sound: the discomfort of wearing headphones and the intrusiveness of external speakers.

[0017] 2. Coordinated control of spatial sound field to avoid interference. This invention sets up a collaborative control module to monitor the spatial overlap between the directional sound beam and the noise reduction zone in real time. When the overlap exceeds a set threshold, the driving parameters of the directional sound wave transmitter or the filtering coefficient of the active noise reduction module are dynamically adjusted to make the two staggered in space or frequency domain, thereby effectively avoiding the mutual interference between directional sound and anti-phase sound waves. This technical means overcomes the technical prejudice that directional sound and anti-phase sound waves are difficult to coexist, which is usually believed by those skilled in the art, and ensures that sound quality and noise reduction effect are achieved at the same time.

[0018] 3. Adaptive pointing and noise reduction region matching This invention, by incorporating an attitude sensor and a user position detection unit, can acquire the pointing angle of the outer shell and / or the spatial position of the user's ear in real time. The collaborative control module dynamically adjusts the emission direction of the directional sound beam based on this information, ensuring that the sound beam is always aimed at the user's ear. Simultaneously, the active noise cancellation module adjusts the spatial distribution of the anti-phase sound waves according to the user's position, causing the noise cancellation zone to automatically follow the focus of the sound beam, ensuring that the user's ear is always centered in the noise cancellation zone. This dynamic tracking function greatly improves the practicality and convenience of the device, allowing users to move freely within a certain range without having to maintain a fixed posture.

[0019] 4. Optimized microphone and speaker layout to ensure stable feedback. This invention places an error microphone array around the active noise-canceling speaker group, with each error microphone equidistant from the adjacent active noise-canceling speaker. Meanwhile, a reference microphone is placed on the back or side of the housing. This layout allows the reference microphone to collect clean ambient noise signals, avoiding the direct pickup of directional sound beams or anti-phase sound waves. The error microphones can effectively pick up residual noise after noise reduction, providing accurate error input for the adaptive filtering algorithm. At the same time, it avoids the instability of the acoustic feedback loop, ensuring the stable operation of the active noise-canceling system.

[0020] 5. Adaptive volume adjustment enhances listening comfort. This invention uses a volume adaptive adjustment module to analyze the sound pressure level near the user's ear based on the residual noise signal collected by the error microphone array, and automatically adjusts the volume of the directional sound beam. When the ambient noise increases, the volume is automatically increased to maintain clarity; when the ambient noise decreases, the volume is automatically decreased to avoid discomfort. This function allows users to obtain a constant and comfortable listening experience in different noise environments without the need to manually adjust the volume.

[0021] 6. Compact structure, controllable cost, and wide range of applications. This invention adopts a modular design, integrating functions such as directional sound emission, active noise reduction, signal processing, and attitude perception into one unit. The shell size can be flexibly designed to adapt to different application scenarios. No additional wearing parts are required. It is suitable for various scenarios such as office, home, vehicle, outdoor live broadcast, and hearing aids, and has broad engineering application prospects and commercial value. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0023] Figure 2 This is a schematic diagram of the mounting structure of the acoustic lens of the present invention.

[0024] Figure 3 This is a schematic diagram of the structure of the control circuit board for the present invention.

[0025] Figure 4 This is a schematic diagram of the structure of the directional sound wave transmitter of the present invention.

[0026] Figure 5 This is a schematic diagram of the structure of the back of the outer casing of the present invention.

[0027] Figure 6 This is a schematic diagram of the structure of the back of the sound insulation panel of the present invention.

[0028] Figure 7 This is a schematic diagram of the cross-sectional structure of the outer shell of the present invention.

[0029] Figure 8This is a schematic diagram of the structure of Embodiment 3 of the present invention.

[0030] Figure 9 This is a schematic diagram of the control flow of the present invention.

[0031] Figure Labels In the diagram: 1. Outer shell; 101. Sound insulation panel; 102. Sound receiving channel; 103. Front-end kit; 104. Rotating ring; 105. Sound receiving hole; 2. Directional sound wave transmitter; 3. Reference microphone; 4. Error microphone array; 5. Active noise-canceling speaker group; 6. Control circuit board; 601. Directional sound drive module; 602. Active noise cancellation module; 603. Cooperative control module; 7. Acoustic lens; 8. Attitude sensor; 9. User position detection unit; 10. Volume adaptive adjustment module. Detailed Implementation

[0032] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] This invention proposes a directional audio system with active noise cancellation. By integrating a directional sound wave transmitter 2, an active noise-canceling speaker group 5, and an error microphone array 4 onto the front surface of the same housing 1, with the active noise-canceling speaker group 5 and the error microphone array 4 distributed around the directional sound wave transmitter 2, the system achieves integrated directional audio and active noise cancellation technology. Furthermore, by setting a collaborative control module 603, the spatial superposition relationship between the directional sound beam and the noise cancellation zone is dynamically adjusted to avoid mutual interference between directional sound and anti-phase sound waves. By setting an attitude sensor 8 and an acoustic lens 7, the directional sound beam is always aimed at the user's ear, and the noise cancellation zone automatically follows. By setting a volume adaptive adjustment module 10, the volume of the directional sound beam is automatically adjusted to adapt to changes in environmental noise. These technical means work together to solve the technical problems of existing directional audio systems being unable to actively eliminate environmental noise, the need for active noise cancellation devices to be worn, and the omnidirectional radiation of sound.

[0034] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0035] Example 1: A desktop directional sound system with active noise cancellation Please see Figures 1 to 3As shown, the present invention provides a technical solution: a directional sound system with active noise cancellation function, including a housing 1, a directional sound wave transmitter 2, an ambient noise pickup unit, an error microphone array 4, an active noise cancellation speaker group 5, and a control circuit board 6.

[0036] See Figure 1 and Figure 2 As shown, the outer shell 1 is a cuboid structure, made of aluminum alloy and CNC machined, with good heat dissipation and electromagnetic shielding performance. The outer shell 1 has dimensions of 500mm (length) × 300mm (width) × 500mm (height). Its front end is the acoustic output surface, and the surface has mounting holes and acoustic sound transmission holes corresponding to each acoustic component. The inner cavity of the outer shell 1 is provided to accommodate the control circuit board 6 and other electronic components. The bottom of the outer shell 1 is provided with an anti-slip silicone pad, which can be placed stably on the table.

[0037] See Figure 4 As shown, the directional acoustic wave transmitter 2 is located at the center of the front end face of the housing 1, and is used to emit a directional audible sound beam toward the target area. In this embodiment, the directional acoustic wave transmitter 2 is a 16×16 piezoelectric ceramic ultrasonic transducer array with an element spacing of 10mm and a working frequency of 40kHz. Each piezoelectric ceramic transducer has a diameter of 8mm and a thickness of 2mm, and has a high electromechanical coupling coefficient and a high Curie temperature. All transducer elements are arranged in a rectangular grid to form a emitting surface with a total size of 160mm×160mm. By controlling the phase of the driving signal of each element, electronic beamforming can be achieved, making the emitted sound beam highly directional, with a -3dB beam angle of approximately 12°. The directional sound driving module 601 uses a double-sideband modulation algorithm to modulate the input audible sound signal (20Hz-20kHz) onto a 40kHz ultrasonic carrier. After power amplification, it drives the ultrasonic transducer array. When the ultrasonic wave propagates in the air, it restores the audible sound through a nonlinear self-demodulation effect, forming a directional sound beam.

[0038] See Figures 5 to 7As shown, a sound insulation plate 101 is provided inside the housing 1. The ambient noise pickup unit is located at the center of the back of the sound insulation plate 101. The ambient noise pickup unit is a reference microphone 3, which can be a MEMS microphone with a sensitivity of -26dBFS and a signal-to-noise ratio of 64dB. Its direction is backward. A sound receiving hole 105 and a sound receiving channel 102 are also provided on the side wall of the housing 1. The sound receiving hole 105 is horn-shaped. One end 102 of the sound receiving channel 102 is detachably connected to the inner wall of the housing 1, so that the sound receiving channel 102 is connected to the sound receiving hole 105. The sound receiving channel 102 and the sound receiving hole 105 work together to collect the surrounding noise and transmit it to the reference microphone 3. The sound insulation plate 101 reduces the influence of the directional sound wave transmitter 2 or the active noise cancellation speaker group 5 on the reference microphone 3, so as to avoid the reference microphone 3 directly receiving the sound played by the directional sound wave transmitter 2 or the active noise cancellation speaker group 5, and ensure that the reference signal is a pure ambient noise signal.

[0039] See Figure 4 As shown, the error microphone array 4 is disposed on the front end of the housing 1 and surrounds the directional sound wave transmitter 2. In this embodiment, the error microphone array 4 consists of 4 MEMS microphones of the same model as the reference microphone 3. The 4 error microphones are located around the directional sound wave transmitter 2, 55mm away from the center of the directional sound wave transmitter 2, and are arranged in a rectangular shape. Each error microphone is connected to the main control circuit board through a flexible circuit board and is used to collect residual noise signals in the target area.

[0040] See Figure 4 As shown, the active noise cancellation speaker group 5 is disposed on the front end face of the housing 1 and distributed at the four corners of the directional sound wave transmitter 2. In this embodiment, the active noise cancellation speaker group 5 consists of four miniature electric speakers with a diameter of 20mm, model AAC miniature speakers, rated power of 1W, and impedance of 4Ω. The four speakers are located at the four corners of the directional sound wave transmitter 2, with a distance of 40mm from the center of the directional sound wave transmitter 2. The error microphone array 4 is located on the periphery of the active noise cancellation speaker group 5. Each error microphone is equidistant from the adjacent active noise cancellation speaker. This layout allows each error microphone to effectively pick up the superposition signal of the anti-phase sound wave and residual noise generated by the corresponding active noise cancellation speaker, which is beneficial to the convergence of the adaptive filtering algorithm.

[0041] See Figure 3 As shown, the control circuit board 6 is located at the front end of the sound insulation plate 101 inside the housing 1, and integrates a digital signal processor, power amplifier, power management module, etc. The control circuit board 6 includes a directional sound drive module 601, an active noise reduction module 602, and a collaborative control module 603.

[0042] See Figure 9As shown, the directional sound driving module 601 uses a digital signal processor as its core, runs a double-sideband modulation algorithm, modulates the input audible sound signal onto a 40kHz ultrasonic carrier, and outputs 16×16 PWM signals. After being amplified by MOSFET power, the signals drive the ultrasonic transducer array. The directional sound driving module 601 also integrates a phase control unit, which can independently adjust the phase of the driving signal of each array element to achieve electronic beam deflection.

[0043] See Figure 9 As shown, the active noise cancellation module 602 adopts a feedforward active noise cancellation architecture and uses the FxLMS adaptive filtering algorithm. The active noise cancellation module 602 uses the ambient noise signal collected by the reference microphone 3 as the reference input x(n) and the residual noise signal collected by the error microphone array 4 as the error signal e(n). Through adaptive iteration, it calculates the optimal filtering coefficient w(n) to generate an anti-phase noise signal y(n) with the same amplitude but opposite phase as the noise reaching the user's ear, driving the active noise cancellation speaker group 5 to play. The iterative formula of the FxLMS algorithm is: w(n+1) = w(n) + μ·x'(n)·e(n) Where μ is the convergence step size, and x'(n) is the reference signal after being filtered by the secondary channel transfer function estimation.

[0044] See Figure 9 As shown, the collaborative control module 603 is used to adjust the spatial superposition relationship between the directional sound beam and the noise reduction zone to avoid sound quality degradation caused by sound wave interference. The collaborative control module 603 calculates the spatial position of the main lobe of the directional sound beam and the spatial range of the noise reduction zone in real time. When the overlap between the two exceeds the set threshold, for example, when the overlap between the two reaches 80%, the carrier frequency of the directional sound wave transmitter 2 is finely adjusted (within ±1kHz range) or the filtering coefficient of the active noise reduction module 602 is adjusted to make the two slightly offset in the frequency domain, thereby reducing mutual interference.

[0045] See Figure 1 and Figure 2As shown, in this embodiment, a front-end assembly 103 may also be provided on the front end face of the outer casing 1. An adjustable acoustic lens 7 is provided directly in front of the directional sound wave transmitter 2. The acoustic lens 7 is flat, with a thickness of about 5-8 mm, and its effective diameter is slightly larger than the emitting surface of the directional sound wave transmitter 2. The acoustic lens 7 is installed in the front-end assembly 103 by screwing. The initial gap between the lens and the directional sound wave transmitter 2 is 2 mm. A rotating ring 104 is provided on the front-end assembly 103, which is connected to the acoustic lens 7. The user can adjust the lens according to the listening distance. The rotating ring 104 on the rotating front end assembly 103 drives the acoustic lens 7 to move back and forth along the acoustic axis. The rotating ring 104, the front end assembly 103, and the acoustic lens 7 form a mechanical rotating mechanism. The acoustic lens 7 can move within a range of ±5mm, thereby changing the focusing distance, which is adjustable from 0.5m to 2m. The acoustic lens 7 is made of 3D printed phononic crystal material and has a periodic microstructure inside, which can realize the axial adjustment of the sound beam focus. The acoustic lens 7 changes its effective focal length according to the set distance, so that the directional sound beam is precisely focused on the user's ear.

[0046] Work process: The user places the speaker on their desk, adjusts its orientation so that the front of it faces them, and upon activation, the directional sound wave transmitter 2 projects an audio signal toward the user's ears. Simultaneously, the reference microphone 3 picks up ambient office noise, such as keyboard or air conditioner sounds, while the error microphone array 4 picks up residual noise near the user's ears. The active noise cancellation module 602 calculates the anti-phase sound wave and drives the active noise cancellation speaker group 5 to play it, forming a noise reduction zone with a diameter of approximately 30cm around the user's head. The collaborative control module 603 monitors the spatial overlap between the directional sound beam and the noise reduction zone in real time to ensure their coordinated coexistence. Furthermore, the user can manually adjust the rotating ring to set the listening distance as needed, thereby ensuring that the directional sound beam is precisely focused on the user's ears.

[0047] Test results: In a 50dB background noise environment, the clarity of the audio signal heard by the user is improved by 80%, and the sound intensity heard by people 1 meter away is less than 40dB, effectively avoiding sound interference. The noise reduction effect allows users to hear the content clearly at 65dB without having to increase the volume. According to acoustic measurements, at the user's ear position, the active noise cancellation module achieves a noise reduction of 15-20dB in the 100Hz-1kHz frequency band. The directivity of the directional sound beam causes the sound pressure level attenuation of about 12dB at a distance of 30° from the main axis.

[0048] Example 2: A directional sound system with attitude tracking and active noise cancellation See Figure 9As shown, the main difference between this embodiment and embodiment 1 is that the outer shell 1 is equipped with an attitude sensor 8. The attitude sensor 8 is a six-axis inertial measurement unit, which can be an MPU6050. It includes a three-axis accelerometer and a three-axis gyroscope, and the sampling frequency is 100Hz. It is used to detect the pointing angle of the outer shell 1 in real time, such as pitch angle, yaw angle and roll angle. In addition, in this embodiment, the directional acoustic wave transmitter 2 adopts a ring piezoelectric transducer array, which facilitates the realization of electronic beam scanning.

[0049] The attitude sensor 8 is fixed on the control circuit board 6 inside the housing 1. Its coordinate axis is aligned with the geometric coordinate axis of the housing 1. When the device is used for the first time, the user needs to face the front of the speaker to the ear and press the calibration button through the preset calibration program. The attitude sensor 8 records the attitude angle at this time as the zero point reference. After that, the attitude sensor 8 outputs the attitude change amount relative to the zero point reference in real time.

[0050] The attitude tracking function of the collaborative control module 603: Based on the attitude signal detected by the attitude sensor 8, the collaborative control module 603 calculates the change in the azimuth angle of the user's ear relative to the speaker. When the user turns their head, the attitude sensor 8 detects the change in the angle of the outer shell 1 relative to the user's ear. The collaborative control module 603 calculates the angle Δθ that the sound beam needs to deflect, and achieves electronic beam scanning by adjusting the phase delay of each element of the ring ultrasonic transducer array. The phase control algorithm of the ring array is as follows: For a circular array, when the target beam pointing angle is (θ0, φ0), the phase delay of the i-th element is: Where k is the wave number, and x_i, y_i, and z_i are the array element coordinates, the directional sound beam can be rapidly deflected within a horizontal ±30° and a vertical ±20° range by updating the phase delay in real time, with a response time of less than 50ms. After the directional sound beam deflects, the active noise reduction module 602 regenerates the noise reduction zone based on the signal collected by the error microphone array 4. Since the error microphone array 4 is distributed around the directional sound wave transmitter 2, its spatial coverage range matches the sound beam deflection range. Therefore, the noise reduction zone automatically follows the sound beam focus, ensuring that the user's ear is always in the center of the noise reduction zone.

[0051] Work process: When the user places the speaker on the table and turns it on, the speaker automatically enters posture tracking mode. When the user sits in front of the speaker, the speaker detects the relative position of the outer shell 1 and the user's ear through the posture sensor 8, and directs the directional sound beam toward the user. When the user turns their head left or right or changes their sitting posture, the posture sensor 8 detects the posture change in real time, and the collaborative control module 603 adjusts the direction of the sound beam in milliseconds to ensure that the sound always follows the user's ear. At the same time, the active noise cancellation module 602 automatically adjusts the position of the noise cancellation zone according to the current sound beam direction, so that the user's head is always in the center of the noise cancellation zone.

[0052] Test results: Within a range of ±30° of horizontal head rotation, the directional sound beam tracking error is less than 3°. The user's subjective auditory evaluation is that the sound always comes from directly in front, the noise reduction effect remains stable throughout the tracking range, and the noise reduction amount changes by less than 3dB.

[0053] Example 3: A portable directional sound system with active noise cancellation See Figure 8 and Figure 9 As shown, the main difference between this embodiment and embodiment 1 is that the outer shell 1 is a cylindrical structure, made of high-strength ABS plastic injection molding, with a diameter of 60mm and a height of 80mm. It has a built-in rechargeable lithium battery with a capacity of 3000mAh and a battery life of 6 hours. The surface of the outer shell 1 is provided with a waterproof and dustproof mesh cover, which has IP54 protection capability.

[0054] The directional acoustic wave transmitter 2 uses a small piezoelectric MEMS ultrasonic array with a size of 20mm×20mm, 8×8 array elements, a working frequency of 45kHz, and an element spacing of 5mm. The MEMS ultrasonic transducer is manufactured using CMOS compatible technology and features small size, low power consumption, and good consistency, making it suitable for integration into portable devices.

[0055] The active noise-canceling speaker group 5 consists of two miniature speakers with a diameter of 15mm and a rated power of 0.5W, which are symmetrically arranged on the left and right sides of the directional sound wave transmitter 2. The error microphone array 4 consists of two MEMS microphones, which are located 5mm outside the two active noise-canceling speakers 5 respectively. The reference microphone 3 is located at the bottom of the housing 1.

[0056] The control circuit board 6 uses a low-power Bluetooth chip, such as Nordic nRF52840, as the main controller, integrating an audio codec, power amplifier, and active noise cancellation algorithm. The directional sound drive module uses a single-sideband modulation algorithm to reduce power consumption and improve efficiency. The active noise cancellation module adopts a feedback active noise cancellation architecture, which only uses the signal from the error microphone array 4 for feedback control. It has a simple structure, low power consumption, and is suitable for portable devices.

[0057] User location detection: This embodiment can be equipped with a user location detection unit 9, which adopts an ultra-wideband positioning module. By detecting the UWB tag worn by the user, such as a wristband or mobile phone, the distance and angle between the UWB tag and the speaker are detected to achieve the user's ear position positioning. The UWB positioning accuracy can reach the centimeter level, which is suitable for vehicle or outdoor scenarios.

[0058] Work process: Users can place the speaker on a table, clip it onto a backpack strap, or put it in a car cup holder to play music via Bluetooth to their mobile phones. The speaker uses a directional sound wave transmitter 2 to project sound toward the user's ears, while the active noise cancellation module 602 reduces interference from ambient wind noise, human voices, engine noise, etc. When the user moves, the UWB positioning module tracks the user's position in real time, and the collaborative control module 603 dynamically adjusts the direction of the sound beam to ensure that the user is always in the optimal listening area.

[0059] Test results: In outdoor environments with a background noise level of 60dB, the directional sound beam is clearly audible when the user is 1m away from the speaker, while it is almost inaudible to others at a distance of 60° from the main axis. The active noise cancellation module reduces low-frequency wind noise (100-500Hz) by 10-15dB. In a car environment with a speed of 60km / h and an interior noise level of approximately 65dB, users can make clear calls without raising their volume, and the other party reports significantly clearer voice communication than traditional in-car hands-free systems.

[0060] Example 4: A control method for a directional sound system with active noise cancellation function See Figure 9 As shown, this embodiment provides a control method for a directional sound system with active noise cancellation, applied to the directional sound system with active noise cancellation described in any of the above embodiments. The method includes the following steps: S1: Emit a directional sound beam. The directional sound wave transmitter 2 emits a directional audible sound beam toward the target area. Specifically, the directional sound drive module 601 modulates the input audible sound signal. Using a double-sideband modulation or single-sideband modulation algorithm, the audible sound signal is modulated onto an ultrasonic carrier (frequency range 30kHz-50kHz). After power amplification, the ultrasonic transducer array is driven to generate a highly directional sound beam.

[0061] S2: Acquire noise signals. Acquire ambient noise signals through reference microphone 3 and residual noise signals in the target area through error microphone array 4. Reference microphone 3 is set on the back of housing 1 and the acquired ambient noise signals are used as reference inputs for active noise reduction algorithms. Error microphone array 4 is set on the front face of housing 1 and surrounds directional sound wave transmitter 2 to acquire residual noise signals near the user's ears and serve as error inputs for adaptive filtering algorithms.

[0062] S3: Generate an inverse noise signal. The active noise reduction module 602 generates an inverse noise signal based on the ambient noise signal and the residual noise signal. The active noise reduction module 602 runs the FxLMS adaptive filtering algorithm, using the ambient noise signal collected by the reference microphone 3 as the reference input x(n) and the residual noise signal collected by the error microphone array 4 as the error signal e(n). The optimal filtering coefficient w(n) is calculated through adaptive iteration to generate an inverse noise signal y(n) with the same amplitude and opposite phase as the noise reaching the user's ear.

[0063] S4: Playing anti-phase noise to form a noise reduction zone. The anti-phase noise signal is played through the active noise-canceling speaker group 5 to form a noise reduction zone in the target area. The active noise-canceling speaker group 5 is distributed around the directional sound wave transmitter 2. The played anti-phase sound wave is superimposed with the environmental noise that propagates to the user's ear to achieve noise cancellation and form a noise reduction zone with a diameter of about 20-30cm around the user's ear.

[0064] S5: Cooperative control and interference avoidance. The cooperative control module 603 monitors the spatial overlap between the directional sound beam and the noise reduction zone in real time. When the overlap exceeds a set threshold, the driving parameters of the directional sound wave transmitter 2 or the filtering coefficient of the active noise reduction module 602 are adjusted to make them spatially or in the frequency domain staggered to avoid mutual interference. Specifically, one or more of the following measures can be taken: Fine-tune the carrier frequency of the directional sound wave transmitter 2, shifting it by ±500Hz, so that the main frequency band of the directional sound beam is offset from the operating frequency band of the active noise reduction module 602; Adjust the filtering coefficient of the active noise reduction module 602 so that the anti-phase sound wave complements the main lobe of the directional sound beam in spatial distribution, rather than overlaps it; By using electronic beamforming technology, the directional sound beam is slightly deflected to offset it from the center of the noise reduction zone. At the same time, the masking effect of human hearing is utilized to ensure that the auditory experience is not affected.

[0065] Optional step S6: Attitude tracking and sound beam following. The orientation angle of the housing 1 is detected by the attitude sensor 8, and the optimal emission direction of the directional sound beam is automatically calculated based on the preset user ear position or the real-time position obtained by the user position detection unit 9. The sound beam dynamically tracks the user's head movement by adjusting the phase delay of the directional sound wave transmitter 2 or by controlling the rotation of the acoustic lens 7 through the rotating ring 104, and the noise reduction zone follows the focus of the directional sound beam.

[0066] Optional step S7: Adaptive volume adjustment. The adaptive volume adjustment module 10 analyzes the sound pressure level near the user's ear based on the residual noise signal collected by the error microphone array 4, and automatically adjusts the volume of the directional sound beam. When the ambient noise increases, the volume of the directional sound beam is automatically increased to maintain a constant signal-to-noise ratio; when the ambient noise decreases, the volume is automatically decreased to avoid discomfort. The volume adjustment range can be set to ±15dB, and the adjustment speed is gradual to avoid discomfort caused by sudden changes.

[0067] Example: A cloud-based intelligent integrated modular directional sound system This embodiment, based on the previous embodiments, further introduces a modular integrated assembly structure, remote communication and edge computing functions, and a cloud-based intelligent control platform, aiming to solve the problems of unified deployment, remote operation and maintenance, intelligent scheduling, and sound field collaborative optimization of multiple directional sound systems in large venues.

[0068] Modular integrated assembly structure The outer shell 1 is designed as a standardized basic unit module, with magnetic or snap-on mechanical quick-release interfaces and spring pin electrical contacts on its back and sides. Multiple outer shells 1 can be spliced ​​together in a two-dimensional or three-dimensional array in the horizontal or vertical direction through the quick-release interfaces to form a "directional sound wall" or "spatial partition noise reduction array".

[0069] Each housing 1 has an integrated cascaded communication interface on its control circuit board 6. When multiple units are spliced ​​together, the system automatically establishes an internal communication network through electrical contacts. The main control unit user specifies or the collaborative control module 603 automatically elects and coordinates the working parameters of each unit to achieve the expansion of the sound field coverage area and the acoustic consistency calibration at the splicing seams. This integrated assembly structure allows users to flexibly increase or decrease the number of audio units according to the actual space size, reducing deployment costs and improving system scalability.

[0070] Integration of remote communication and edge computing functions Based on the original module, the control circuit board 6 further integrates remote communication and edge computing functions. The remote communication function supports Wi-Fi, 5G cellular networks and Bluetooth Low Energy protocols to establish a two-way data link with the cloud server and user smart terminals. The edge computing function is implemented by the digital signal processor in the collaborative control module 603 or an additionally configured neural network processing unit. It is used to execute real-time collaborative control algorithms for user voiceprint recognition, environmental noise feature extraction and directional sound beam and noise reduction zone locally, and only upload key status information to the cloud to reduce cloud load and network latency.

[0071] Cloud-based intelligent control platform The system also includes a cloud server that runs an acoustic environment digital twin model and a multi-objective optimization scheduling engine. Users can remotely control and intelligently operate the audio system through an application or web dashboard installed on their smart terminals. Specific functions include: Remote status monitoring and fault early warning: The cloud receives the operating temperature, power amplifier current, consistency index of error microphone array 4 and noise reduction margin of active noise reduction module 602 uploaded by each directional speaker unit in real time. When any parameter deviates from the preset threshold, the cloud automatically generates a fault work order and pushes it to the maintenance personnel through the application to realize predictive maintenance.

[0072] Cloud-based acoustic scene adaptation: Users can select the current application scene within the application. Based on the selected scene, the cloud downloads the optimal directional sound driving parameters, the initial coefficients of the active noise reduction filter, and the interference avoidance threshold of the cooperative control module 603 from the acoustic parameter library to the local device. At the same time, the cloud can utilize environmental noise feature data uploaded by multiple users to continuously optimize the noise reduction algorithm model through federated learning, and push the updated model parameters to all devices of the same model.

[0073] Intelligent control and voice interaction: Users can send voice commands through smart terminal applications or third-party smart speakers, such as: "Aim the directional speakers in the living room at the left side of the sofa", "Reduce the ambient noise reduction intensity of the speakers in the study to 60%", or "Start movie viewing mode, point the left channel directional sound beam at the main position and the right channel at the secondary position". After receiving the command, the cloud interprets the intent through natural language processing and calls the application interface of the collaborative control module 603 to automatically adjust the phase delay of the corresponding directional sound wave transmitter 2 or the focusing position of the acoustic lens 7, while adjusting the output intensity of the active noise cancellation speaker group 5.

[0074] Multi-device spatial collaboration: When multiple directional sound systems of this embodiment are deployed in an open space, the cloud obtains the real-time coordinates of all users through the user position detection unit 9 on each device and runs a spatial sound field conflict avoidance algorithm. When the cloud detects that there is a risk of cross-interference between the directional sound beams of two adjacent devices, it instructs one of the devices to temporarily fine-tune its carrier frequency or actively enable the frequency domain staggering strategy of the collaborative control module 603, thereby avoiding "sound crosstalk" and ensuring that each user obtains an independent and private listening space.

[0075] Work process example Taking the "smart conference room" scenario as an example: the administrator pre-configures multiple directional speaker systems of this embodiment in the cloud backend, assembles them into an array through magnetic interfaces, and evenly covers multiple seats of the long conference table.

[0076] Before the meeting begins, all devices are remotely woken up via the application, and the "meeting mode" parameter set is automatically sent to the cloud. After each participant is seated, the system automatically detects the position of their ears through the user position detection unit 9, and the collaborative control module 603 accurately projects the corresponding directional sound beam to the participant's ears, while activating active noise cancellation to eliminate the steady-state noise from the central air conditioning and projector fan.

[0077] When the speaker initiates the "simultaneous interpretation" function through the application, the cloud routes the audio streams of different languages ​​to the directional speaker units corresponding to different seats. Participants can clearly hear the translated content in their selected language from their own seats without wearing headphones, and there is absolutely no crosstalk between adjacent seats. During the meeting, the cloud continuously monitors the working status of each unit and displays data such as noise reduction effect and beam pointing accuracy to the administrator in the form of a visual dashboard. After the meeting, the system automatically generates an energy consumption report and a device health report, and supports one-click shutdown.

[0078] Multi-device collaboration capabilities break through physical limitations: The cloud-based spatial collaboration algorithm effectively solves the problem of sound interference when multiple directional speakers coexist at close range, making it possible to provide multiple users with private, clear, and noise-free personal audio spaces in a limited space.

[0079] Through the above method, the present invention achieves a deep integration of directional sound beam emission and active noise reduction, providing users with an immersive personal audio experience while ensuring sound quality.

[0080] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0081] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0082] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0083] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

[0084] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0085] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0086] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0087] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "over," or "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," or "beneath" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0088] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0089] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A directional sound system with active noise cancellation function, characterized in that, include: Outer shell (1); A directional sound wave transmitter (2) is disposed on the front end face of the housing (1) for emitting a directional audible sound beam toward the target area; An ambient noise pickup unit includes a reference microphone (3) for acquiring ambient noise signals; An error microphone array (4) is disposed on the front end face of the housing (1) and surrounds the directional sound wave transmitter (2) for collecting residual noise signals in the target area; An active noise-canceling speaker group (5) is disposed on the front end face of the housing (1) and distributed around the directional sound wave transmitter (2) for generating noise-canceling anti-phase sound waves; A control circuit board (6), the control circuit board (6) comprising: A directional sound driving module (601) is used to drive the directional sound wave transmitter (2); An active noise cancellation module (602) is used to generate an anti-phase noise signal based on the ambient noise signal and the residual noise signal, and drive the active noise cancellation speaker group (5); The collaborative control module (603) is used to adjust the spatial superposition relationship between the directional sound beam and the noise reduction zone.

2. The directional sound system with active noise cancellation function according to claim 1, characterized in that, The directional acoustic wave transmitter (2) is a piezoelectric ultrasonic transducer array, and its array elements are arranged in a ring or rectangle; the active noise reduction loudspeaker group (5) consists of at least two miniature electric loudspeakers, which are evenly distributed around the directional acoustic wave transmitter (2).

3. The directional sound system with active noise cancellation function according to claim 1, characterized in that, The error microphone array (4) is located on the periphery of the active noise cancellation speaker group (5), and each error microphone is equidistant from the adjacent active noise cancellation speaker.

4. The directional sound system with active noise cancellation function according to claim 1, characterized in that, The front end face of the housing (1) is provided with an adjustable acoustic lens (7), which is made of a material with gradually changing acoustic impedance and is used to adjust the focusing position of the directional sound beam and the matching degree of the noise reduction area.

5. The directional sound system with active noise cancellation function according to claim 1, characterized in that, An attitude sensor (8) is provided inside the outer shell (1). The attitude sensor (8) is used to detect the pointing angle of the outer shell (1). The cooperative control module (603) adjusts the emission direction of the directional sound beam according to the attitude signal.

6. The directional sound system with active noise cancellation function according to claim 5, characterized in that, The collaborative control module (603) adjusts the phase delay of the directional sound wave transmitter (2) according to the posture signal and the preset user ear position, so that the directional sound beam dynamically tracks the user's head movement and the noise reduction zone follows the focus of the directional sound beam.

7. The directional sound system with active noise cancellation function according to claim 1, characterized in that, It also includes a user position detection unit (9), which is at least one of a camera, an infrared sensor or an ultra-wideband positioning module, for obtaining the spatial position of the user's ear relative to the shell (1).

8. The directional sound system with active noise cancellation function according to claim 1, characterized in that, The control circuit board (6) also includes a volume adaptive adjustment module (10), which is used to analyze the sound pressure level near the user's ear based on the residual noise signal collected by the error microphone array (4) and automatically adjust the volume of the directional sound beam.

9. The directional sound system with active noise cancellation function according to claim 1, characterized in that, The directional sound driving module (601) uses a double-sideband modulation or single-sideband modulation algorithm to modulate the audible sound signal onto the ultrasonic carrier; the active noise reduction module (602) uses a feedforward, feedback or hybrid active noise reduction architecture and runs an adaptive filtering algorithm.

10. A control method for a directional sound system with active noise cancellation, applied to the directional sound system with active noise cancellation as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1: A directional audible beam is emitted toward the target area via a directional sound wave transmitter (2); S2: Acquire ambient noise signals through a reference microphone (3) and acquire residual noise signals in the target area through an error microphone array (4); S3: The active noise reduction module (602) generates an inverse noise signal based on the environmental noise signal and the residual noise signal; S4: The anti-phase noise signal is played through the active noise-canceling speaker group (5) to form a noise reduction zone in the target area; S5: The spatial overlap between the directional sound beam and the noise reduction zone is monitored in real time by the collaborative control module (603). When the overlap exceeds the set threshold, the driving parameters of the directional sound wave transmitter (2) or the filtering coefficient of the active noise reduction module (602) are adjusted so that the two are staggered in space and / or frequency domain to avoid mutual interference.

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