A speaker capable of eliminating electromagnetic interference, elimination method and electronic musical instrument

Abstract

This invention belongs to the field of musical instruments, specifically relating to a loudspeaker capable of eliminating electromagnetic interference, an elimination method, and an electronic musical instrument. The loudspeaker capable of eliminating electromagnetic interference includes: a sounding diaphragm; at least two sets of driving components, each driving component including a cooperating magnetic circuit system and a voice coil, the voice coil being fixed to the sounding diaphragm and used to generate an alternating magnetic field under the drive of an electrical driving signal; wherein the at least two driving components are configured such that, when an electrical driving signal is input, the total magnetic flux change of the alternating magnetic fields generated by each driving component at the target element cancels each other out, and the driving force generated by each driving component on the sounding diaphragm is in the same direction. This invention eliminates interference by having at least two sets of driving components jointly drive the same sounding diaphragm, causing the alternating magnetic fields generated by each component to cancel each other out at the target element, while simultaneously ensuring that the driving forces on the diaphragm are superimposed in the same direction for normal sound production.

Description

Technical Field

[0001] This invention belongs to the field of musical instruments, specifically relating to a loudspeaker capable of eliminating electromagnetic interference, an elimination method, and an electronic musical instrument. Background Technology

[0002] In electroacoustic devices (such as electronic musical instruments and smart speakers), it is often necessary to integrate speakers with sensitive components such as pickups and microphones in close proximity. However, when the voice coil of a speaker is operating, it carries an alternating current, which not only drives the diaphragm to produce sound but also radiates an alternating magnetic field as a current carrier. This magnetic field is easily picked up by nearby components (such as electric guitar pickups), amplified by the circuit, and then used to drive the speaker again, thus forming a positive feedback coupling loop that can cause a piercing self-excited howl or severe signal distortion.

[0003] To address this issue, traditional solutions typically employ physical isolation (increasing distance), adding magnetic shielding, or introducing anti-phase compensation structures. Physical isolation limits the compactness and integrated design of the equipment; magnetic shielding increases weight and cost, and its shielding effect on low-frequency alternating magnetic fields is limited. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a loudspeaker, a method for eliminating electromagnetic interference, and an electronic musical instrument. By having at least two sets of driving components jointly drive the same sound-producing diaphragm, the alternating magnetic fields generated by each component cancel each other out at the target element to eliminate interference, while ensuring that the driving forces on the diaphragm are superimposed in the same direction for normal sound production.

[0005] This invention provides a loudspeaker capable of eliminating electromagnetic interference, comprising: The sound-producing diaphragm; At least two sets of driving components, each driving component including a cooperating magnetic circuit system and a voice coil, the voice coil being fixed to the sound-producing diaphragm, the voice coil being used to generate an alternating magnetic field under the drive of an electric driving signal; The at least two driving components are configured such that, when an electric driving signal is input, the total magnetic flux change of the alternating magnetic field generated by each driving component at the target element cancels each other out, and the driving force generated by each driving component on the sound-producing diaphragm is in the same direction. Furthermore, the drive assembly is provided in two sets, and the magnetic field directions of the magnetic circuit systems in the two sets of drive assemblies are opposite.

[0006] Furthermore, the voice coils in the two sets of drive components are wound in opposite directions, and the two sets of drive components are configured to be driven by the same electrical drive signal.

[0007] Furthermore, the voice coils in both sets of drive components are wound in the same direction, and the two sets of drive components are configured to be driven by electrical drive signals that are out of phase with each other.

[0008] Furthermore, the magnetic circuit system includes: Magnetic column; A ring magnet is sleeved outside the magnetic guide post, and a magnetic gap is formed between the inner wall of the ring magnet and the outer wall of the magnetic guide post. A magnetic guide plate is disposed on the side of the annular magnet away from the sound-producing diaphragm and is connected to the end of the magnetic guide post; Wherein, at least a portion of the winding of the voice coil is placed in the magnetic gap; The magnetic circuit system also includes a magnetic conductor disposed on the side of the annular magnet near the sound-producing diaphragm.

[0009] Furthermore, the voice coil includes a coil frame and a winding, the winding being wound on the coil frame, the coil frame being fixed to the sound-producing diaphragm, and at least a portion of the winding being placed in the magnetic gap.

[0010] Furthermore, the drive component is provided in two sets; It also includes a control unit, which is used to dynamically adjust the gain of one group of the driving components based on the residual components of the alternating magnetic field generated by each driving component picked up by the target element, so as to suppress the residual components; The control unit is configured to perform the following operations in calibration mode: Output a reference signal, and simultaneously drive the first driving component with a first gain and drive the second driving component with a second gain; Acquire a feedback signal generated by the target element in response to the reference signal, the feedback signal characterizing the residual component of the alternating magnetic field generated by the first drive component and the second drive component at the target element; The following iteration is performed repeatedly at multiple preset sampling times: Calculate the current residual component based on the feedback signal; The gain adjustment is obtained by multiplying the current residual component by a fixed step size; The second gain is updated with the aforementioned gain adjustment amount, causing the residual component to approach zero.

[0011] Furthermore, the drive component is provided in two sets; It also includes a control unit, which is used to dynamically adjust the gain of one group of the driving components based on the residual components of the alternating magnetic field generated by each driving component picked up by the target element, so as to suppress the residual components; The control unit is configured to perform the following operations in calibration mode: Output a reference signal to drive the first driving component with a first gain and drive the second driving component with an initial value of the second gain. Acquire a first feedback signal generated by the target element in response to the reference signal, the first feedback signal characterizing a first residual component at the target element; The second gain is adjusted to be the sum of the initial value of the second gain and a preset increment; Acquire a second feedback signal generated by the target element in response to the reference signal, the second feedback signal representing a second residual component at the target element after adjusting the second gain; Based on the first feedback signal, the second feedback signal, and the preset increment, calculate the estimated value of the system gain; In subsequent sampling periods, the current feedback signal generated by the target element is acquired, and the current feedback signal is normalized with the estimated value of the system gain to obtain the actual error estimate; The actual error estimate is subjected to proportional-integral control operation to obtain a gain adjustment amount, and the second gain is updated with the gain adjustment amount to make the residual component approach zero.

[0012] The present invention also provides a method for eliminating electromagnetic interference using a loudspeaker, comprising the following steps: An electric drive signal is input to the at least two sets of drive components to drive the voice coil of each drive component to generate an alternating magnetic field and jointly drive the sound-producing diaphragm to vibrate and produce sound; The input configuration of the electric drive signal is such that the total magnetic flux change of the alternating magnetic field generated by each of the drive components cancels each other out at the target element, and the driving force generated by each of the drive components on the sound-producing diaphragm is in the same direction.

[0013] The present invention also provides an electronic musical instrument, including the aforementioned loudspeaker capable of eliminating electromagnetic interference; The target component is a microphone.

[0014] The beneficial effects of this invention are that it provides a loudspeaker capable of eliminating electromagnetic interference. By setting at least two sets of driving components, and ensuring that the changes in the total magnetic flux of the alternating magnetic fields generated by each driving component cancel each other out at the target element, while simultaneously ensuring that the driving force on the sound-producing diaphragm is in the same direction, the path for the loudspeaker and the target element to form a positive feedback loop through magnetic field coupling is fundamentally cut off. While ensuring that the normal sound production performance of the loudspeaker is not affected, the electromagnetic interference generated by the loudspeaker on the target element is effectively suppressed. This allows the loudspeaker to be integrated with sensitive components such as pickups at close range, realizing the functional feasibility and stability of integrated audio systems such as electric guitars with built-in loudspeakers.

[0015] Furthermore, the arrangement of at least two sets of driving components on the sound-producing diaphragm provides additional design freedom for optimizing the speaker's sound performance. Without altering the core configuration used to suppress electromagnetic interference in this embodiment (i.e., the total magnetic flux of the alternating magnetic fields of each driving component cancels out at the target element, and the driving force on the sound-producing diaphragm is in the same direction), optimization can provide flexible design space for improving the speaker's sound quality. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the explosion of the electronic musical instrument in this invention; Figure 2 This is a schematic diagram of the speaker structure in this invention; Figure 3 This is a schematic diagram of the driving component in this invention; Figure 4 This is a schematic diagram of the operation of the control unit in this invention.

[0017] In the diagram, 1-speaker; 11-diaphragm; 12-drive assembly; 121-magnetic circuit system; 1211-magnetic post; 1212-ring magnet; 1213-magnetic gap; 1214-magnetic plate; 1215-magnetic component; 122-voice coil; 1221-coil frame; 1222-winding; 2-pickup. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0020] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0021] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0023] like Figure 1-Figure 4 As shown, the present invention provides a loudspeaker capable of eliminating electromagnetic interference, comprising: The sound-producing diaphragm 11 is used to generate sound by vibrating and pushing air, and is the sound-producing component of the loudspeaker. As a sound-producing carrier shared by all driving components 12, the sound-producing diaphragm 11 can concentrate the driving force generated by each driving component 12 onto the same sound-producing body, and work together to drive the sound-producing diaphragm 11 to vibrate and produce sound.

[0024] At least two sets of driving components 12 are provided. Each driving component 12 includes a cooperating magnetic circuit system 121 and a voice coil 122. The voice coil 122 is fixed to the sound-producing diaphragm 11 and is used to generate an alternating magnetic field under the drive of an electrical driving signal. The magnetic circuit system 121 and the voice coil 122 cooperate to form a complete electro-mechanical-acoustic conversion unit, converting the input electrical driving signal into a mechanical force that drives the sound-producing diaphragm 11, while simultaneously generating an alternating magnetic field radiating outward.

[0025] In this configuration, the at least two drive components 12 are configured such that, upon input of an electric drive signal, the total change in magnetic flux of the alternating magnetic fields generated by each drive component 12 at the target element cancels each other out. The target element is a component susceptible to electromagnetic interference, such as a pickup in an electric guitar. Because the vector sum of the magnetic flux of the alternating magnetic fields generated by each drive component 12 at the target element approaches zero, the target element cannot effectively pick up interference signals from the speaker, thereby disrupting the conditions for forming a positive feedback coupling loop between the speaker and the target element.

[0026] Furthermore, the driving force exerted by each driving component 12 on the sound-producing diaphragm 11 is in the same direction. Although the phase relationship of the alternating magnetic fields generated by each driving component 12 is configured to cancel each other out in space for the target element, the direction of the Ampere force they apply to the sound-producing diaphragm 11 is consistent. This means that while suppressing electromagnetic interference, the driving forces of each driving component 12 do not weaken each other, but rather superimpose, ensuring that the speaker can output sound normally and efficiently. The electromagnetic interference-eliminating loudspeaker provided in this embodiment, by setting at least two sets of driving components 12, ensures that the changes in the total magnetic flux of the alternating magnetic fields generated by each driving component 12 cancel each other out at the target element, and that the driving force on the sound-producing diaphragm 11 is in the same direction, fundamentally cuts off the path for the positive feedback loop formed by magnetic field coupling between the loudspeaker and the target element. While ensuring that the normal sound production performance of the loudspeaker is not affected, it effectively suppresses the electromagnetic interference generated by the loudspeaker on the target element, allowing the loudspeaker to be integrated with sensitive components such as pickups at close range, realizing the functional feasibility and stability of integrated audio systems such as electric guitars with built-in loudspeakers.

[0027] Furthermore, the arrangement of at least two sets of drive components 12 on the sound-producing diaphragm 11 provides additional design freedom for optimizing the speaker's sound performance. Without changing the core configuration used to suppress electromagnetic interference in this embodiment (i.e., the total magnetic flux of the alternating magnetic fields of each drive component 12 cancels out at the target element, and the driving force on the sound-producing diaphragm 11 is in the same direction), optimization can also provide flexible design space for improving the speaker's sound quality.

[0028] It should be noted that the drive components 12 can be set in two, three, four or more groups, as long as the total magnetic flux change of the alternating magnetic fields generated by all drive components 12 at the target element cancels each other out. The setting principle is as follows: all drive components 12 are divided into a first type with a first magnetic field direction and a second type with an opposite second magnetic field direction according to the magnetic field direction of the magnetic circuit system 121. The sum of the alternating magnetic flux generated by the first type of drive components 12 and the sum of the alternating magnetic flux generated by the second type of drive components 12 are equal in magnitude and opposite in direction at the target element, so that the total magnetic flux change cancels each other out.

[0029] In one preferred embodiment, the drive component 12 is provided in two sets. For ease of explanation, the following description uses two sets of drive components 12 as an example to further elaborate on the specific structure of the present invention.

[0030] The magnetic fields of the magnetic circuit systems 121 in the two sets of drive components 12 are in opposite directions. The permanent magnets of the two sets of magnetic circuit systems 121 are magnetized in opposite directions, which is one of the core configurations for achieving magnetic flux cancellation at the target element while maintaining the same direction of driving force on the sound-producing diaphragm 11. Its working principle is as follows: Since the constant magnetic fields of the two sets of magnetic circuit systems 121 are in opposite directions, when a suitable electrical drive signal is applied to the two sets of voice coils 122, the alternating magnetic fields generated by the two sets of voice coils 122 are in opposite directions in space. By properly configuring the relative positions of the two sets of drive components 12 and the target element, the magnetic flux of the two sets of alternating magnetic fields at the target element can be mutually canceled. At the same time, the two sets of magnetic circuit systems 121 with opposite magnetic field directions, when combined with the correspondingly configured voice coils 122, can cause the two sets of voice coils 122 to experience Ampere forces in the same direction, thereby jointly driving the sound-producing diaphragm 11 to produce sound. This reverse magnetic field configuration allows the system to simultaneously meet the dual requirements of magnetic flux cancellation and driving force superposition without introducing complex phase inversion processing at the circuit end, resulting in a simple structure and high reliability.

[0031] In one embodiment, the voice coils 122 in the two sets of drive components 12 have opposite winding directions, and the two sets of drive components 12 are configured to be driven by the same electrical drive signal. The two sets of voice coils 122 are a first voice coil and a second voice coil, with the winding direction of the first voice coil opposite to that of the second voice coil. The same electrical drive signal is simultaneously input to the first and second voice coils. This is the first voice coil configuration scheme of the present invention to achieve magnetic flux cancellation and thrust superposition. Its working principle is as follows: Since the winding directions of the two sets of voice coils 122 are opposite, when the same electrical drive signal is input, the instantaneous directions of the current flowing through the two sets of voice coils 122 are opposite to each other. According to the law of electromagnetic induction, the alternating magnetic fields generated by the two sets of voice coils 122 are opposite to each other. Combined with the core configuration of the two sets of magnetic circuit systems 121 with opposite magnetic field directions, the alternating magnetic fields generated by the two sets of voice coils 122 achieve magnetic flux cancellation at the target element. Meanwhile, according to Ampere's left-hand rule, currents flow in opposite directions in the two sets of magnetic circuit systems 121 with opposite magnetic field directions. The Ampere forces on the two sets of voice coils 122 are in the same direction, jointly driving the sounding diaphragm 11. The advantage of this scheme is that there is no need to set up an inverting amplifier circuit or a differential output circuit on the circuit side. Only one electrical drive signal is needed to simultaneously meet the dual requirements of magnetic flux cancellation and thrust superposition. The circuit structure is simple and the system has high reliability.

[0032] In one embodiment, the voice coils 122 in the two sets of drive components 12 have the same winding direction, and the two sets of drive components 12 are configured to be driven by electrical drive signals that are out of phase with each other.

[0033] The two sets of voice coils 122 have the same winding direction, but the electrical drive signals input to the two sets of voice coils 122 are out of phase. This is the second voice coil configuration scheme of the present invention to achieve magnetic flux cancellation and thrust superposition, forming an equivalent technical effect to the first scheme. Its working principle is as follows: Since the two sets of voice coils 122 have the same winding direction, when an inverse electrical drive signal is input, the instantaneous directions of the current flowing through the two sets of voice coils 122 are opposite. According to the law of electromagnetic induction, the alternating magnetic fields generated by the two sets of voice coils 122 are in opposite directions. Combined with the core configuration of the two sets of magnetic circuit systems 121 with opposite magnetic field directions, the alternating magnetic fields generated by the two sets of voice coils 122 achieve magnetic flux cancellation at the target element. At the same time, according to the left-hand rule of Ampere's force, the currents flowing through the two sets of magnetic circuit systems 121 with opposite magnetic field directions are in opposite directions, and the Ampere forces on the two sets of voice coils 122 are in the same direction, jointly driving the sounding diaphragm 11. The advantage of this scheme is that the two sets of voice coil 122 windings are wound in the same direction, and can share the same winding process, which helps improve the winding consistency of the two sets of voice coil 122 and reduces the impact of manufacturing tolerances on the accuracy of flux cancellation. Meanwhile, the inverting electric drive signal can be provided by a differential amplifier circuit or a dual-channel inverting output controlled by an MCU, enabling flexible signal phase management on the circuit side. These two schemes are technically equivalent and can be flexibly selected according to actual manufacturing process conditions and circuit design requirements.

[0034] In one embodiment, the magnetic circuit system 121 includes: Magnetic post 1211; A ring magnet 1212 is sleeved on the outside of the magnetic post 1211, and a magnetic gap 1213 is formed between the inner wall of the ring magnet 1212 and the outer wall of the magnetic post 1211. A magnetic guide plate 1214 is disposed on the side of the annular magnet 1212 away from the sound-producing diaphragm 11 and is connected to the end of the magnetic guide post 1211; At least a portion of the winding of the voice coil 122 is placed in the magnetic gap 1213.

[0035] This embodiment provides a specific implementation structure of the magnetic circuit system 121. The magnetic post 1211, the ring magnet 1212, and the magnetic plate 1214 together form a closed magnetic circuit. The ring magnet 1212 provides a constant magnetic field, and the magnetic post 1211 and the magnetic plate 1214 guide the magnetic field to concentrate at the magnetic gap 1213. The magnetic gap 1213 is the working area of ​​the voice coil 122 winding. When an electrical drive signal is applied to the winding, the current-carrying conductor generates an Ampere force under the action of the constant magnetic field in the magnetic gap 1213, driving the voice coil 122 and the fixed diaphragm 11 to vibrate. This structure efficiently concentrates the magnetic energy of the ring magnet 1212 in the magnetic gap 1213, providing a stable and uniform working magnetic field for the voice coil 122, which is beneficial for improving the electro-electric conversion efficiency and reducing distortion. Simultaneously, the magnetic plate 1214 is located on the side of the ring magnet 1212 away from the diaphragm 11 and is connected to the end of the magnetic post 1211, serving the dual functions of closing the magnetic circuit and providing fixed support. It should be noted that each set of drive components 12 has an independent magnetic circuit system 121. The two sets of magnetic circuit systems 121 each form an independent magnetic circuit, and there is no magnetic circuit interference between them, which facilitates the independent assembly of the two sets of drive components 12 and the independent configuration of the magnetic field direction.

[0036] The magnetic circuit system 121 further includes a magnetic conductor 1215, which is disposed on the side of the annular magnet 1212 near the sound-producing diaphragm 11.

[0037] The magnetic guide element 1215, as a supplementary magnetic guide element to the magnetic circuit system 121, is located between the annular magnet 1212 and the voice coil 122 winding area. Its function is to further optimize the magnetic field distribution in the magnetic gap 1213. The magnetic guide element 1215 can guide the magnetic lines of force of the annular magnet 1212 near the sound-producing diaphragm 11 to the magnetic gap 1213 more evenly, making the magnetic field strength distribution along the vibration direction of the voice coil 122 in the magnetic gap 1213 more uniform. This helps to reduce the nonlinear distortion caused by the non-uniform magnetic field during the reciprocating motion of the voice coil 122, and improve the sound quality of the loudspeaker. On the other hand, the setting of the magnetic guide element 1215 can also reduce the magnetic leakage at the magnetic gap 1213, so that more magnetic energy is concentrated in the working area of ​​the voice coil 122 winding, further improving the electro-electric conversion efficiency. Meanwhile, the outer walls of the magnetic guide element 1215 and the magnetic guide post 1211 together define the inner and outer boundaries of the magnetic gap 1213. The radial distance between them is the width of the magnetic gap 1213. The machining accuracy of the magnetic guide element 1215 directly affects the dimensional consistency of the magnetic gap 1213, which is of positive significance for ensuring the magnetic circuit symmetry of the two sets of drive components 12. It should be noted that the magnetic guide elements 1215 are independently set in the two sets of magnetic circuit systems 121. The two sets of magnetic guide elements 1215 are symmetrically arranged on the side of the annular magnet 1212 near the sound diaphragm 11. This helps to keep the magnetic circuit performance of the two sets of drive components 12 consistent, thereby achieving more precise mutual cancellation of alternating magnetic flux at the target element.

[0038] In one embodiment, the voice coil 122 includes a coil frame 1221 and a winding 1222, the winding 1222 being wound on the coil frame 1221, the coil frame 1221 being fixed to the sound-producing diaphragm 11, and at least a portion of the winding 1222 being placed in the magnetic gap 1213.

[0039] The coil frame 1221 serves as a supporting structure for the voice coil 122, with one end fixedly connected to the sound-producing diaphragm 11, transmitting the driving force generated by the winding 1222 to the sound-producing diaphragm 11. The winding 1222 is made of conductive material wound around the outer wall of the coil frame 1221, forming a multi-layered helical tubular structure. In operation, the winding 1222 is placed in the magnetic gap 1213 of the magnetic circuit system 121. When an electrical drive signal is applied to the winding 1222, the current-carrying conductor experiences an Ampere force within the constant magnetic field of the magnetic gap 1213. This force is transmitted through the coil frame 1221 to the sound-producing diaphragm 11, driving the diaphragm 11 to vibrate and produce sound. The fixed connection between the coil frame 1221 and the sound-producing diaphragm 11 can be achieved by bonding, snap-fitting, or integral molding, ensuring the rigidity and reliability of the driving force transmission path. It should be noted that each of the two sets of driving components 12 has an independent coil frame 1221 for its voice coil 122, and the two sets of coil frames 1221 are symmetrically arranged on the sound-producing diaphragm 11.

[0040] In one embodiment, the drive component 12 is provided in two sets; It also includes a control unit, which is used to dynamically adjust the gain of one group of the driving components 12 according to the residual component of the alternating magnetic field generated by each driving component 12 picked up by the target element, so as to suppress the residual component; The control unit is configured to perform the following operations in calibration mode: Output a reference signal, and simultaneously drive the first driving component 12 with a first gain and drive the second driving component 12 with a second gain; The feedback signal generated by the target element in response to the reference signal is obtained, and the feedback signal characterizes the residual component of the alternating magnetic field generated by the first drive component 12 and the second drive component 12 at the target element; The following iteration is performed repeatedly at multiple preset sampling times: Calculate the current residual component based on the feedback signal; The gain adjustment is obtained by multiplying the current residual component by a fixed step size; The second gain is updated with the aforementioned gain adjustment amount, causing the residual component to approach zero.

[0041] This embodiment is a preferred embodiment that introduces an active calibration function. In actual manufacturing, due to the unavoidable manufacturing tolerances of the magnetic circuit systems 121 and voice coils 122 of the two sets of drive components 12, coupled with assembly errors in the installation position, the alternating magnetic fields generated by the two sets of drive components 12 are difficult to completely cancel at the target component, and a residual component will always remain. If this residual component is large enough, it may still form a positive feedback loop with the target component and subsequent circuits, causing self-excitation. This embodiment sets up a control unit to enter calibration mode when the speaker system is turned on or at a specific time, and adaptively adjusts the drive gain of the two sets of drive components 12 to compensate for the inconsistencies caused by manufacturing and assembly errors.

[0042] The control unit operates as follows: In calibration mode, the control unit outputs a reference signal, such as a test signal in the ultrasonic frequency band, which is inaudible to the human ear and does not affect the user experience. This reference signal simultaneously drives the first driving component 12 and the second driving component 12. However, due to the difference in the actual parameters of the two driving components 12, the target element will still pick up a weak feedback signal, which reflects the magnitude of the current residual component. The control unit calculates the current residual component at each sampling time iteratively and updates the second gain according to the fixed-step gradient descent method: each time, the residual component is multiplied by a preset fixed step size (small constant), and the resulting product is added to the second gain as a gain adjustment. Since there is a definite gradient relationship between the residual component and the direction of the second gain adjustment, after several iterations, the residual component will converge exponentially to a level close to zero. The value of the fixed step size must meet the convergence condition, that is, the product of the step size and the system gain must be between 0 and 2. In practice, a sufficiently small step size can be used to ensure a stable convergence process. This control scheme requires minimal computing resources, does not require prior knowledge of system gain and other parameters, and is easy to implement in embedded MCUs, providing a reliable guarantee for the speaker to maintain low electromagnetic interference performance in actual use.

[0043] In one specific implementation of this embodiment, taking two sets of drive components 12 as an example: the control unit uses a fixed-step gradient descent method for gain adjustment. The following parameters are defined: A Gain of the first driving component ( GainA This value can be set to a fixed value during the calibration process; B Gain of the second driving component ( GainB ), which is the variable to be adjusted during the calibration process; D The relative value of the current residual component, characterized by the feedback signal generated by the target element in response to the reference signal, is obtained by measurement; sSystem gain is an unknown constant coefficient determined by factors such as magnetic signal space loss, target component conversion efficiency, and internal circuit gain. s >0; m Fixed step size, which is a preset small positive constant, must satisfy... m s <2 to ensure convergence; E： error, E = A - B .

[0044] The relative value of the residual component picked up by the target element D The following relationship is satisfied between the gain of each driving component: D=s· (AB) .

[0045] The calibration process is as follows: Initialization: Settings B For initial values ​​(such as) B =0), keep A Set to a preset fixed gain; Iterative update: At each sampling time, perform the following update operation: Measurement D=s·(AB) renew B←B+μ·D Repeat this step until the residual component D approaches zero (or reaches the preset number of iterations / convergence threshold).

[0046] Explanation of the principle: Error after update E′=A-(B+μ·D)=AB-μ·s·(AB)=(1-μ·s·E Because 0 < μs <2, error E The system converges to zero exponentially. The step size μ must be chosen to be small enough to guarantee any possible system gain. s Lower convergence, m The actual value can be determined by experience or set through system debugging.

[0047] This specific implementation method fully utilizes the relative values ​​of the residual components obtained from the target element. D As a feedback quantity, there is no need to identify the system gain in advance. s The iterative process involves only multiplication and addition operations, with minimal resource consumption, making it suitable for execution in low-cost embedded MCUs. It can automatically balance the gain during power-on calibration, effectively compensating for inconsistencies caused by manufacturing tolerances and assembly errors, and ensuring that the total alternating magnetic flux change at the target component is suppressed to the maximum extent under normal operating conditions.

[0048] In one embodiment, the drive component 12 is provided in two sets; It also includes a control unit, which is used to dynamically adjust the gain of one group of the driving components 12 according to the residual component of the alternating magnetic field generated by each driving component 12 picked up by the target element, so as to suppress the residual component; The control unit is configured to perform the following operations in calibration mode: Output a reference signal to drive the first driving component 12 with a first gain and drive the second driving component 12 with a second initial gain value; Acquire a first feedback signal generated by the target element in response to the reference signal, the first feedback signal characterizing a first residual component at the target element; The second gain is adjusted to be the sum of the initial value of the second gain and a preset increment; Acquire a second feedback signal generated by the target element in response to the reference signal, the second feedback signal representing a second residual component at the target element after adjusting the second gain; Based on the first feedback signal, the second feedback signal, and the preset increment, calculate the estimated value of the system gain; In subsequent sampling periods, the current feedback signal generated by the target element is acquired, and the current feedback signal is normalized with the estimated value of the system gain to obtain the actual error estimate; The actual error estimate is subjected to proportional-integral control operation to obtain a gain adjustment amount, and the second gain is updated with the gain adjustment amount to make the residual component approach zero.

[0049] This is another preferred embodiment of introducing active calibration function, employing a proportional-integral control method with initial estimation. Its core idea consists of two stages: the first stage involves actively applying a known gain disturbance and observing the system's response change, thereby deriving the system's gain parameters; the second stage uses the obtained system gain parameters to reconstruct the subsequently measured feedback signal, obtaining the true error, and then achieving rapid convergence and long-term stability through the proportional-integral controller.

[0050] In the first stage, the control unit is unaware of the overall signal attenuation factor from the drive component 12 to the target element. This attenuation factor is determined by multiple factors, including the spatial propagation loss of the magnetic field, the conversion efficiency of the target element, and the internal circuit gain, and varies slightly from device to device due to manufacturing tolerances. To obtain this unknown parameter, the control unit first records the magnitude of the residual signal under the current gain setting, then actively fine-tunes the gain of one of the drive components 12 by a known small amount, and measures the change in the residual signal again. The difference between the two residual signals is entirely caused by this known gain fine-tuning; therefore, by dividing the difference between the two measurements by the known fine-tuning amount, the system's attenuation factor can be accurately estimated. The entire process requires only two measurements and one active fine-tuning, and is completely transparent to the user.

[0051] In the second stage, the control unit uses the estimated system attenuation factor to restore the feedback signal measured by the target element to the true gain deviation between the two sets of drive components 12. Since the feedback signal is a reduced version of the true deviation after system attenuation, directly adjusting based on the feedback signal easily underestimates the magnitude of the deviation, resulting in a slow response. However, the normalized value is an estimate of the true deviation, which the control unit can use to perform fast and accurate gain adjustment using a proportional-integral control strategy. The proportional control part responds instantly according to the magnitude of the current deviation, with a large adjustment for large deviations and a small adjustment for small deviations; the integral control part accumulates historical deviations and continuously compensates for long-standing small residuals, eliminating steady-state error. The combination of the two makes the gain of the second drive component 12 quickly approach the optimal equilibrium point, and the residual component converges to a level close to zero in a very short time and can remain stable for a long time. Compared with the fixed step size iterative method, this embodiment, because the system parameters are identified in advance, provides a clear direction and scale for the adjustment process, resulting in faster convergence and higher accuracy.

[0052] In one specific implementation of this embodiment, the control unit employs a proportional-integral control method with initial estimation for gain adjustment. For ease of description, the following parameters are defined: A The gain of the first driving component can be set to a fixed value during calibration. B The gain of the second driving component is a variable to be adjusted during the calibration process; D The relative value of the current residual component, characterized by the feedback signal generated by the target element in response to the reference signal, is obtained by measurement. D=s·(AB) ; s System gain is an unknown coefficient determined by factors such as magnetic signal space loss, target component conversion efficiency, and internal circuit gain. s >0, for a single devices It is relatively constant, but may vary slightly with external parameters such as temperature and usage environment; d The preset increment is a known small quantity, for example... d =0.1, used to actively perturb the second gain to estimate the system gain; System gain s The estimated value was obtained from the calculation in the first stage; Ê Actual error estimation Ê=D / , representing the true deviation E=AB The estimated value; Kp : Proportionality coefficient, which is a positive constant, for example Kp =1; Ki The integral coefficient is a positive constant, for example... Ki =0.1; I : The integral accumulation term, with an initial value of 0; T Sampling period, for example T =0.1 seconds; m Fixed step size, which is a preset small positive constant, must satisfy... m s <2 to ensure convergence.

[0053] The calibration process is carried out in two stages, with the following steps: Output a reference signal to drive a first driving component with a first gain and drive a second driving component with a second initial gain value; obtain a first feedback signal generated by the target element in response to the reference signal, wherein the first feedback signal characterizes a first residual component at the target element; Relative value of the first residual component: D 0 =s·(AB 0 ) This step establishes the initial error state under the current gain configuration. At this point, the first drive component operates at a fixed gain. A Running, the second driving component starts at initial values B 0 operation, due to manufacturing tolerances and assembly errors in the two sets of drive components, A and B 0 are not equal, therefore there is a residual alternating magnetic flux at the target element, the relative magnitude of which is measured as D 0. D 0 represents the true deviation. E =AB 0 by system gain s The reaction after attenuation.

[0054] The control unit adjusts the second gain to the sum of the initial value of the second gain and a preset increment. Specifically, it adjusts the second gain from... B 0 is adjusted to: B 1 =B 0 +d The second feedback signal generated by the target element in response to the same reference signal is obtained again and denoted as the relative value of the second residual component: D 1 =s·(AB 1 ) This step involves actively applying a known gain perturbation. d Observe the changes in the system response. d This is a known small quantity preset by the control unit, and its value must balance the requirements of estimation accuracy and not causing audible noise. Because the second gain is actively changed... d The residual component at the target element changes accordingly, from D 0 becomes D 1. The difference between the two measurements is entirely due to the known gain perturbation. d This provides a basis for subsequently inferring the unknown system gain s.

[0055] Based on the first feedback signal, the second feedback signal, and the preset increment, an estimated value of the system gain is calculated. This is derived from the difference between the two measurements: D 0 -D 1 =s·(AB 0 )-s·(AB 0 -δ)=sδ The estimated value of the system gain can be obtained:

[0056] The system gain *s* is a bridging parameter connecting the drive gain deviation and the feedback signal from the target element. It comprehensively reflects factors such as the spatial loss of the magnetic signal propagating from the two sets of drive components to the target element, the conversion efficiency of the target element in converting magnetic flux into an electrical signal, and the gain of the internal signal chain. Due to differences in manufacturing tolerances, assembly precision, and component parameters, each device... s The specific values ​​vary. Through two active measurements and a known increment, the control unit automatically identifies the estimated value of s without relying on any preset parameters. . The accuracy of the signal directly affects the convergence performance of subsequent PI control. dThe larger the value, the higher the estimated signal-to-noise ratio, but an excessively large value... d A brief, audible noise may occur during the calibration process, therefore d A smaller, compromised amount is usually chosen.

[0057] In subsequent sampling periods, the current feedback signal generated by the target component is acquired, and the current feedback signal is normalized using the estimated system gain to obtain an actual error estimate. In each sampling period, the control unit acquires the current feedback signal. D ,calculate: Ê=D /

[0058] because D=s·(AB) When the estimate is accurate ≈ s Sometimes, Ê ≈ AB = E The significance of normalization lies in the feedback signal. D Is it the system gain s A scaled-down version after significant attenuation, if directly based on D Gain adjustment is performed, but the adjustment range is significantly insufficient due to attenuation, resulting in slow convergence. Divide by The true gain bias estimate was then recovered. Ê This ensures that the adjustment amount of subsequent PI control is proportional to the actual deviation, eliminates the influence of the attenuation factor, and guarantees that the adjustment strength and direction match the actual situation.

[0059] The actual error estimate is subjected to proportional-integral control operation to obtain a gain adjustment amount, and the second gain is updated with the gain adjustment amount to make the residual component approach zero.

[0060] Design a PI controller with the following continuous-domain expression: B(t)=Kp·Ê(t)+Ki·∫ 0 t Ê(τ)dτ in Kp、Ki For positive numbers (e.g.) Kp =1, Ki =0.1). This PI controller consists of a proportional term. Kp·Ê(t) and integral terms Ki·∫ 0 t Ê(τ)dτ It consists of two parts. The proportional term responds instantly to the magnitude of the current error, adjusting larger increments for larger errors and smaller increments for smaller errors, ensuring rapid adjustment. The integral term accumulates all historical errors since calibration began. Even if the current error is very small, the integral term will continue to compensate for long-standing minor residual errors, eliminating steady-state errors that cannot be avoided by proportional adjustment alone.

[0061] Discretization is implemented as follows: Initialize the integral term I =0, sampling period T (like T =0.1).

[0062] For each sampling period, perform the following operations: Measure the current feedback signal D ,calculate Ê=D / ; Update points accumulation items: I←I+Ê·T Update the second gain: B←B+μ·D Here, μ is a fixed step size, which has the same meaning as the step size in Algorithm 1, and is a preset small positive number. Since s is fixed and accurately estimated, the controller can make AB quickly approach zero.

[0063] The above steps are repeated until the residual components converge to below a preset threshold or the preset number of iterations is reached, at which point the calibration is complete. Afterward, the control unit exits calibration mode and drives the two sets of drive components into normal operation with the calibrated gain configuration.

[0064] Compared to the fixed-step gradient descent method, this specific implementation method, because it pre-identifies the system gain s, is equivalent to having the direction and scale of error adjustment clearly defined before adjustment, resulting in faster convergence. Simultaneously, the integral action in the PI controller eliminates steady-state error, achieving higher precision flux cancellation. Furthermore, minor drifts in the system gain s caused by factors such as temperature changes and environmental variations can be automatically re-identified and compensated for during the next power-on calibration, ensuring the speaker maintains excellent low electromagnetic interference performance throughout long-term use.

[0065] The present invention also provides a method for eliminating electromagnetic interference using a loudspeaker, comprising the following steps: An electric drive signal is input to the at least two sets of drive components 12 to drive the voice coil 122 of each drive component 12 to generate an alternating magnetic field and jointly drive the sound-producing diaphragm 11 to vibrate and produce sound; The input configuration of the electric drive signal is such that the total magnetic flux change of the alternating magnetic field generated by each of the drive components 12 at the target element cancels each other out, and the driving force generated by each of the drive components 12 on the sound diaphragm 11 is in the same direction.

[0066] The electromagnetic interference elimination method for loudspeakers provided in this embodiment eliminates electromagnetic interference at its source and cuts off the positive feedback self-excitation circuit by rationally configuring the electric drive signals, so that the alternating magnetic fields generated by each drive component cancel each other out at the target element. At the same time, it ensures that the driving forces of each drive component on the sound-producing diaphragm are superimposed in the same direction, effectively suppressing interference while ensuring the high-efficiency sound production performance of the loudspeaker, and achieving a perfect balance between electromagnetic compatibility and acoustic output.

[0067] The present invention also provides an electronic musical instrument, including the aforementioned loudspeaker capable of eliminating electromagnetic interference; The target component is a microphone 2.

[0068] This electronic musical instrument integrates an electromagnetic interference-eliminating speaker and a pickup 2 into the same body, such as an electric guitar, electric bass, or other electro-acoustic instrument with a pickup 2. The pickup 2 is used to pick up the string vibration signal through electromagnetic induction, and the electromagnetic interference-eliminating speaker is used to convert the processed and amplified audio signal into sound output. Because the speaker uses the aforementioned configuration of at least two sets of drive components 12, the total magnetic flux change of the alternating magnetic field generated by it cancels each other out at the pickup 2. The pickup 2 cannot effectively pick up the interference signal from the speaker, thereby cutting off the positive feedback self-excitation loop between the speaker, pickup, signal processing circuit, and speaker. The speaker and pickup 2 can coexist in close proximity within the instrument body, without the need for additional large gain limiting or notch filtering measures in the signal processing circuit or power amplifier circuit to suppress self-excitation. The playing experience is guaranteed, and the built-in speaker enables autonomous sound production, allowing for playing and monitoring without an external speaker.

[0069] In one embodiment, the loudspeaker capable of eliminating electromagnetic interference and the pickup 2 are arranged symmetrically on the left and right sides of the instrument body. Since the alternating magnetic field generated by each driving component 12 in the loudspeaker is distributed in space with a certain symmetry, placing the pickup 2 in the equilibrium position of this symmetrical distribution can maximize the magnetic flux cancellation effect, further reduce the residual magnetic flux introduced by the installation position deviation, and ensure the reliability of self-excitation suppression.

[0070] The electronic musical instrument may also include a control unit, which can be mounted on a circuit board inside the instrument body and electrically connected to the pickup 2 and the speaker capable of eliminating electromagnetic interference. The control unit receives the audio signal output from the pickup 2, processes it through effects and amplifies its power, and then drives the speaker capable of eliminating electromagnetic interference to produce sound. At the same time, the control unit can execute the aforementioned calibration mode at power-on or at a specific time, automatically adjusting the gain of each drive component 12 to suppress residual magnetic flux, so that the system maintains stable low electromagnetic interference performance over a long period of time.

[0071] The above description is merely an embodiment and does not constitute any limitation on the present invention. Any person skilled in the art can make many possible variations, modifications, or alterations to the technical solutions of the present invention without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, should fall within the protection scope of the present invention.

Claims

1. A loudspeaker capable of eliminating electromagnetic interference, characterized in that, include: Sound-producing diaphragm (11); At least two sets of driving components (12), each driving component (12) includes a cooperating magnetic circuit system (121) and a voice coil (122), the voice coil (122) being fixed on the sound-producing diaphragm (11), the voice coil (122) being used to generate an alternating magnetic field under the drive of an electric driving signal; The at least two drive components (12) are configured such that when an electric drive signal is input, the total magnetic flux change of the alternating magnetic field generated by each drive component (12) at the target element cancels each other out, and the driving force generated by each drive component (12) on the sound diaphragm (11) is in the same direction.

2. The loudspeaker capable of eliminating electromagnetic interference according to claim 1, characterized in that, The drive assembly (12) is provided in two sets, and the magnetic field directions of the magnetic circuit system (121) in the two sets of drive assemblies (12) are opposite.

3. The loudspeaker capable of eliminating electromagnetic interference according to claim 2, characterized in that, The voice coils (122) in the two sets of drive components (12) are wound in opposite directions, and the two sets of drive components (12) are configured to be driven by the same electrical drive signal.

4. The loudspeaker capable of eliminating electromagnetic interference according to claim 2, characterized in that, The voice coils (122) in the two sets of drive components (12) have the same winding direction, and the two sets of drive components (12) are configured to be driven by electrical drive signals that are out of phase with each other.

5. The loudspeaker capable of eliminating electromagnetic interference according to claim 1, characterized in that, The magnetic circuit system (121) includes: Magnetic post (1211); A ring magnet (1212) is sleeved outside the magnetic post (1211), and a magnetic gap (1213) is formed between the inner wall of the ring magnet (1212) and the outer wall of the magnetic post (1211). A magnetic guide plate (1214) is disposed on the side of the annular magnet (1212) away from the sound-producing diaphragm (11) and is connected to the end of the magnetic guide post (1211); Wherein, at least a portion of the winding of the voice coil (122) is placed in the magnetic gap (1213); The magnetic circuit system (121) further includes a magnetic conductor (1215), which is disposed on the side of the annular magnet (1212) near the sound-producing diaphragm (11).

6. The loudspeaker capable of eliminating electromagnetic interference according to claim 5, characterized in that, The voice coil (122) includes a coil frame (1221) and a winding (1222), the winding (1222) being wound on the coil frame (1221), the coil frame (1221) being fixed on the sound-producing diaphragm (11), and at least a portion of the winding (1222) being placed in the magnetic gap (1213).

7. The loudspeaker capable of eliminating electromagnetic interference according to any one of claims 1-6, characterized in that, The drive component (12) is provided in two sets; It also includes a control unit, which is used to dynamically adjust the gain of one set of the driving components (12) based on the residual component of the alternating magnetic field generated by each driving component (12) picked up by the target element, so as to suppress the residual component; The control unit is configured to perform the following operations in calibration mode: Output a reference signal, and simultaneously drive the first driving component (12) with the first gain and drive the second driving component (12) with the second gain. Obtain the feedback signal generated by the target element in response to the reference signal, the feedback signal characterizing the residual component of the alternating magnetic field generated at the target element by the first drive component (12) and the second drive component (12); The following iteration is performed repeatedly at multiple preset sampling times: Calculate the current residual component based on the feedback signal; The gain adjustment is obtained by multiplying the current residual component by a fixed step size; The second gain is updated with the aforementioned gain adjustment amount, causing the residual component to approach zero.

8. The loudspeaker capable of eliminating electromagnetic interference according to any one of claims 1-6, characterized in that, The drive component (12) is provided in two sets; It also includes a control unit, which is used to dynamically adjust the gain of one set of the driving components (12) based on the residual component of the alternating magnetic field generated by each driving component (12) picked up by the target element, so as to suppress the residual component; The control unit is configured to perform the following operations in calibration mode: Output a reference signal to drive the first driving component (12) with a first gain and drive the second driving component (12) with a second initial gain value. Acquire a first feedback signal generated by the target element in response to the reference signal, the first feedback signal characterizing a first residual component at the target element; The second gain is adjusted to be the sum of the initial value of the second gain and a preset increment; Acquire a second feedback signal generated by the target element in response to the reference signal, the second feedback signal characterizing a second residual component at the target element after adjusting the second gain; Based on the first feedback signal, the second feedback signal, and the preset increment, calculate the estimated value of the system gain; In subsequent sampling periods, the current feedback signal generated by the target element is acquired, and the current feedback signal is normalized with the estimated value of the system gain to obtain the actual error estimate; The actual error estimate is subjected to proportional-integral control operation to obtain a gain adjustment amount, and the second gain is updated with the gain adjustment amount to make the residual component approach zero.

9. A method for eliminating electromagnetic interference in a loudspeaker, characterized in that, Using a loudspeaker capable of eliminating electromagnetic interference as described in any one of claims 1-8, the method includes the following steps: An electric drive signal is input to the at least two sets of drive components (12) to drive the voice coil (122) of each drive component (12) to generate an alternating magnetic field and jointly drive the sound-producing diaphragm (11) to vibrate and produce sound; The input configuration of the electric drive signal is such that the total magnetic flux change of the alternating magnetic field generated by each of the drive components (12) at the target element cancels each other out, and the driving force generated by each of the drive components (12) on the sound-producing diaphragm (11) is in the same direction.

10. An electronic musical instrument, characterized in that, Including a loudspeaker capable of eliminating electromagnetic interference as described in any one of claims 1-8; The target component is a microphone (2).

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