CN109997372B - Method for adjusting vibration balance position of vibrating diaphragm and loudspeaker - Google Patents
Method for adjusting vibration balance position of vibrating diaphragm and loudspeaker Download PDFInfo
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- CN109997372B CN109997372B CN201680091207.1A CN201680091207A CN109997372B CN 109997372 B CN109997372 B CN 109997372B CN 201680091207 A CN201680091207 A CN 201680091207A CN 109997372 B CN109997372 B CN 109997372B
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- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
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Abstract
The embodiment of the invention provides a method for adjusting the vibration balance position of a vibrating diaphragm, which comprises the following steps: obtaining the displacement of the vibration balance position of a vibrating diaphragm of a loudspeaker deviating from an initial position, wherein when the vibrating diaphragm works, the vibrating diaphragm takes the vibration balance position as the vibration balance position, and when the vibrating diaphragm takes the initial position as the vibration balance position, the vibrating diaphragm vibrates with a preset maximum amplitude; and inputting a direct current bias current to a voice coil of the loudspeaker according to the displacement so as to calibrate the vibration balance position of the diaphragm to the initial position, wherein the voice coil is positioned on one side of the diaphragm and vibrates along with the diaphragm. Therefore, the loudspeaker can output larger sound pressure level, and better sound output effect is achieved.
Description
Technical Field
The embodiment of the invention relates to the technical field of loudspeakers, in particular to a method capable of dynamically adjusting the vibration balance position of a loudspeaker diaphragm and a loudspeaker.
Background
At present, Smart power amplifiers (Smart PA for short) are generally applied to mobile phone audio, and Smart PA can not only exert the acoustic performance of a loudspeaker, but also well protect the loudspeaker according to the amplitude and temperature characteristics of the loudspeaker (such as a receiver or a loudspeaker). In order to protect the normal operation of the speaker, the intelligent power amplifier usually needs to monitor the vibration displacement of the diaphragm in real time, for example, by establishing a model in advance, the real-time displacement of the diaphragm is predicted, and the diaphragm is ensured to always operate in a safe state. At present, some manufacturers pre-establish a model of the amplitude (equivalent to the vibration amplitude of a voice coil) of a loudspeaker diaphragm and the temperature of the loudspeaker with respect to the input current and the input voltage of the loudspeaker, and then predict the real-time amplitude of the diaphragm by monitoring the voltage and the current signals during working, so as to ensure that the real-time amplitude does not exceed the preset maximum amplitude Z _ max, thereby achieving the purpose of protecting the loudspeaker.
However, some deviations always exist in the physical parameters of mass-produced loudspeaker products, and under the actual working state, the up-and-down displacement of the diaphragm can also cause inconsistency, that is, the loudspeaker products cannot guarantee 100% consistency, and the intelligent power amplifier needs to leave enough margin for protecting the vibrating component. At the present stage, when the displacement of the vibrating diaphragm is predicted in a mode of pre-establishing a model, the maximum amplitude of the vibrating diaphragm is influenced by the detection precision and the model precision, and the original performance of the vibrating assembly cannot be fully exerted.
Disclosure of Invention
The embodiment of the invention provides a method for dynamically adjusting the vibration balance position of a vibrating diaphragm, which can ensure that a loudspeaker outputs at a higher sound pressure level.
The first aspect of the embodiments of the present invention provides a method for adjusting a vibration balance position of a diaphragm, where the method includes the following steps: the method comprises the steps of obtaining the displacement of the vibration balance position of a vibrating diaphragm of a loudspeaker deviating from an initial position, wherein when the vibrating diaphragm works, the vibrating diaphragm takes the vibration balance position as the vibration balance position, and when the vibrating diaphragm takes the initial position as the vibration balance position, the vibrating diaphragm can vibrate with the preset maximum amplitude; and inputting a direct current bias current to a voice coil of the loudspeaker according to the displacement so as to calibrate the vibration balance position of the diaphragm to the initial position, wherein the voice coil is positioned on one side of the diaphragm and vibrates along with the diaphragm. Therefore, the vibration balance position of the loudspeaker diaphragm can be dynamically adjusted, and the loudspeaker is ensured to output at a larger sound pressure level.
According to the first aspect, in a first possible implementation manner of the first aspect, a displacement amount of a vibration balance position of a diaphragm of a loudspeaker from an initial position may be specifically obtained by: firstly, detecting the capacitance value of a capacitor formed between a front cover of the loudspeaker and the diaphragm; then, the displacement amount is calculated based on the capacitance value.
According to the first possible implementation manner of the first aspect, in the second possible implementation manner of the first aspect, the displacement d can be obtained according to the following formulaoffsetCalculating the DC bias current ioffset：
Wherein, KmsBl is a magnetic force factor of the voice coil and the magnetic circuit assembly, which is an equivalent stiffness coefficient of the speaker.
According to the first aspect, in a second possible implementation manner of the first aspect,
according to the first possible implementation manner of the first aspect, in a third possible implementation manner of the first aspect, a magnetic induction device may be further disposed on the diaphragm, and the magnetic induction device measures magnetic induction intensity in the speaker to calculate vibration displacement of the diaphragm; and calculating the displacement of the vibration balance position of the vibrating diaphragm from the initial position according to the vibration displacement of the vibrating diaphragm.
According to a third possible implementation manner of the first aspect, in a fourth possible implementation manner of the first aspect, the magnetic induction device is a hall sensor.
According to any one possible implementation manner of the first aspect to the fourth possible implementation manner of the first aspect, in a fifth possible implementation manner of the first aspect, the method further includes: detecting the temperature of the loudspeaker during working; and determining the direct current bias current input to the voice coil of the loudspeaker according to the displacement and the temperature of the loudspeaker during working. The bias current input to the voice coil is more accurate in consideration of the influence of temperature on the bias current.
A second aspect of the embodiments of the present invention provides a speaker, where the speaker sequentially includes, from top to bottom: the front cover, the vibration component and the magnetic circuit component; the vibration assembly comprises a voice coil and a vibrating diaphragm, wherein the voice coil is positioned on one side of the vibrating diaphragm and vibrates along with the vibrating diaphragm; the loudspeaker also comprises a diaphragm amplitude detection circuit, wherein the diaphragm amplitude detection circuit is used for acquiring the displacement of the vibration balance position of the diaphragm from the initial position, the diaphragm uses the vibration balance position as the vibration balance position when the diaphragm works, and the diaphragm vibrates with the preset maximum amplitude when the diaphragm uses the initial position as the vibration balance position; the loudspeaker also comprises a diaphragm position control circuit, which is used for inputting direct current bias current to a voice coil of the loudspeaker according to the displacement detected by the diaphragm detection circuit so as to calibrate the vibration balance position of the diaphragm to the initial position. The vibration balance position of the vibrating diaphragm of the loudspeaker can be dynamically adjusted, so that the loudspeaker can output at a larger sound pressure level, and the sound loudness is large.
According to a second aspect, in a first possible implementation manner of the second aspect, the front cover is made of a metal material, or a conductive material layer is disposed on the front cover; the vibrating diaphragm is made of metal materials, or a conductive material layer is arranged on the vibrating diaphragm. So that a capacitor can be formed between the front cover and the diaphragm. The vibration amplitude detection circuit is used for obtaining the displacement of the vibration balance position of the vibration diaphragm deviating from the initial position by detecting the capacitance value of a capacitor formed between the front cover and the vibration diaphragm.
According to a second aspect, in a second possible implementation manner of the second aspect, a magnetic induction device is disposed on the diaphragm; the vibration diaphragm amplitude detection circuit measures the magnetic induction intensity in the loudspeaker through the magnetic induction device, and obtains the vibration balance position of the vibration diaphragm deviates from the displacement of the initial position.
According to a second possible implementation manner of the second aspect, in a third possible implementation manner of the second aspect, the magnetic induction device is a hall sensor.
According to a fourth possible implementation manner of the first aspect, in a fourth possible implementation manner of the first aspect, the speaker includes a temperature compensation circuit; the temperature compensation circuit is used for detecting the temperature of the loudspeaker during working; and the diaphragm position control circuit determines the direct current bias current input to the voice coil of the loudspeaker according to the displacement and the temperature of the loudspeaker during working.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is an exploded schematic view of a speaker according to an embodiment of the present invention;
fig. 2(a) is an exploded schematic view of another speaker provided in an embodiment of the present invention;
FIG. 2(B) is an exploded view of the speaker core of FIG. 2 (A);
fig. 3 is a schematic structural diagram of another speaker according to an embodiment of the present invention;
FIG. 4(A) is a schematic diagram of a vibration with a positive offset of the vibration balance position of the diaphragm according to an embodiment of the present invention;
fig. 4(B) is a vibration diagram illustrating that the vibration balance position of the diaphragm is negatively biased according to the embodiment of the present invention;
FIG. 4(C) is a schematic diagram of vibration with no offset of vibration balance position of the diaphragm according to the embodiment of the present invention;
FIG. 5 is a schematic diagram of a capacitance detection circuit according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a capacitance data collector provided in an embodiment of the present invention;
FIG. 7 is a schematic diagram of a circuit for detecting amplitude of a diaphragm according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of a PA chip according to an embodiment of the present invention;
fig. 9 is a schematic diagram of a method for dynamically adjusting a vibration balance position of a diaphragm according to an embodiment of the present invention.
Detailed Description
Embodiments of the present invention will be described below with reference to the accompanying drawings.
Fig. 1 depicts an exploded view of a speaker according to an embodiment of the present invention.
The loudspeaker in fig. 1 comprises from top to bottom in sequence: a front cover 101, a vibration assembly, and a magnetic circuit assembly. The loudspeaker further comprises a housing 106, the front cover 101 and the housing 106 being joined together to enclose a cavity for accommodating the vibration assembly and the magnetic circuit assembly.
The front cover 101 is generally made of metal, and therefore, the front cover is also called a front cover metal plate.
The vibration subassembly includes from last down in proper order: a diaphragm reinforcing part (Dome) 102, a diaphragm (Membrane)103, and a voice Coil (Coil)105, wherein the diaphragm reinforcing part 102 is fixed at the center of the upper surface of the diaphragm 103, and the voice Coil 105 is disposed below the diaphragm 103.
In some embodiments, the vibration module may further include a Flexible Printed Circuit (FPC) 104, the Flexible Circuit 104 is fixed between the diaphragm 103 and the voice coil 105, and the Flexible Circuit 104 is connected to the speaker chip 110. In other embodiments, the flexible circuit board 104 may be fixed on the upper surface of the diaphragm 103. In some embodiments, the flexible circuit board 104 is not part of the vibrating assembly.
The magnetic circuit component comprises from top to bottom in sequence: washer (Washer, also called pole piece) 107, magnet (magnet) 108, and Frame (Frame) 109. A magnetic gap is formed between the washer 107, the magnet 108 and the tub 109, in which the voice coil 105 is suspended. The vibration assembly including the voice coil 105, the diaphragm 103, and the diaphragm reinforcing portion 102 can vibrate upward or downward by the magnetic field of the magnetic circuit assembly. The magnetic circuit component can also be composed of a central washer, a central magnet, a side washer and a side magnet.
Fig. 2(a) is an exploded schematic view of another speaker according to an embodiment of the present invention:
from top to bottom do in proper order: damping (Damping)121, Lower Cover (Lower Cover)122, flexible circuit board 123, Core (Core)124, baffle (Plate)125 and Upper Cover (Upper Cover) 126. The upper cover 126 may also be referred to as a front shell. Flexible circuit board 123 is connected to inner core 124. Wherein the lower cover 122 and the upper cover 126 form a cavity for receiving the inner core 124.
Fig. 2(B) is an exploded schematic view of the core of the loudspeaker of fig. 2 (a):
wherein, the vibration subassembly includes from last to including in proper order down: a Dome (Dome, also called a diaphragm reinforcement) 102, a diaphragm 103, and a voice coil 105. Wherein the dome 102 is fixed to the center of the upper surface of the diaphragm 103.
The magnetic circuit assembly comprises a basin frame 106, a pole piece 107, a magnet 108 and a magnetic Yoke (Yoke)111 from top to bottom in sequence. The pole piece 107, magnet 108, yoke 111 and tub 106 form a magnetic gap therebetween in which the voice coil 105 is suspended. The vibration assembly may vibrate upward or downward by interaction of the magnetic field formed by the magnetic circuit assembly and the voice coil.
The components of the loudspeaker in fig. 1, 2(a) and 2(B) are not essential and are merely schematic. Various components can be deleted according to the requirements of actual products. For example, the baffle 114 and/or damper 112 of FIG. 2(A) may not be required in other embodiments provided by the present invention.
Fig. 3 is a schematic diagram of a moving-coil speaker according to an embodiment of the present invention, where:
301-front cover, 302-diaphragm, 303-upper magnetic circuit part, 304-lower magnetic circuit part, 305-flexure ring, 306-voice coil, 307-magnet. Wherein, the upper magnetic circuit component can comprise a washer (or a pole piece); the lower magnetic circuit assembly may include a Yoke (Yoke). If the front cover 301 is made of metal, the front cover 301 may also be called a front cover metal plate or a metal cover plate.
d1 and d2 are the maximum vibration distances of the diaphragm in the z-direction, i.e., upward and downward, respectively, d1 is generally equal to d2, and the initial position of the diaphragm is the center position of the whole vibration distance. The initial position of the diaphragm, which can also be called the initial position of the voice coil; the vibration of the diaphragm may also be referred to as the vibration of the voice coil. Smart PA can set the maximum amplitude Z of the loudspeaker diaphragm in the Z-directionmaxThe speaker is protected from noise and reliability problems by limiting the maximum amplitude. If the vibration distance of the diaphragm exceeds ZmaxThen, the diaphragm may touch the metal cover plate or the upper magnetic circuit component, and the speaker may generate noise or cause an unreliable problem.
Ideally, the diaphragm vibrates with the initial position as the equilibrium position of the vibration and with the amplitude of d1 or d2 (ideally, d1 is d 2). In this case, the diaphragm can reach the maximum effective vibration distance, and the speaker can exert the best sound production effect.
However, since the speaker is a nonlinear device, several problems occur in operation, which results in that the sound pressure level of the device cannot be fully utilized:
(1) the loudspeaker is a device produced in batch, certain deviation exists in the assembling process, the initial positions of the vibrating diaphragms (or voice coils) of the loudspeaker are difficult to ensure to be identical, and the initial positions of the vibrating diaphragms of part of the loudspeaker are deviated from the designed vibration center position.
(2) When the loudspeaker works, a vibration system consisting of the voice coil, the vibrating diaphragm, the corrugated rim, the front sound cavity and the rear sound cavity has nonlinear characteristics, so that the vibration balance position of the vibrating diaphragm in the z-direction can be deviated relative to the initial position of the vibrating diaphragm.
(3) When the loudspeaker works, due to the temperature effect of the voice coil, the resonance frequency of the loudspeaker can drift, and under the condition that the driving voltage is not changed, the maximum amplitudes at different resonance frequencies are different, so that the risk that the vibration amplitude of the vibrating diaphragm exceeds the safety range exists.
Smart PA from some manufacturers currently uses the following method for diaphragm amplitude protection of a speaker: establishing a model of the vibration amplitude and temperature of the vibration film of the loudspeaker with respect to the input current and voltage of the loudspeaker in advance, predicting the real-time vibration amplitude of the vibration film by monitoring the voltage and current signals during working, and ensuring that the real-time vibration amplitude does not exceed the preset maximum vibration amplitude ZmaxSo as to achieve the purpose of protecting the loudspeaker.
The technical scheme has the following defects that 1: the loudspeaker is a device produced in batch, certain deviation exists in the loudspeaker assembling process, the initial positions of vibrating diaphragms (or voice coils) of the loudspeaker are difficult to ensure to be completely the same, and the initial positions of partial vibrating diaphragms of the loudspeaker are deviated from the designed vibration center position. The offset loudspeaker can more easily reach Z when vibratingmax(if the center of the diaphragm of a loudspeaker is located above the initial position of the diaphragm, it will be easier to reach Z at the upper part during vibrationmax) In the above-mentioned technique, Z is required to be set to protect the speakers having such variationsmaxReduce, prevent that the vibrating diaphragm from contacting the protecgulum metal sheet when the vibration, avoid appearing broken sound scheduling problem. But this solution will lose a part of the acoustic performance for loudspeakers without diaphragm position deviation.
The technical scheme has the following defects that: after the vibration balance position of the loudspeaker diaphragm deviates from the initial position, one side of the loudspeaker diaphragm reaches the maximum amplitude first, the Smart PA protection function can be excited at the moment, and the other side of the loudspeaker diaphragm does not reach the maximum amplitude yet, so that the output capacity of the sound power of the loudspeaker is limited. The dynamic balance of the diaphragm refers to the balance position of the diaphragm vibrating during actual operation.
The influence on the speaker performance when the vibration balance position of the diaphragm deviates from the initial position will be described below with reference to fig. 4(a) to 4 (C).
The vibration balance position of the diaphragm can also be called as the vibration balance position of the voice coil. As shown in fig. 4(C), it is desirable that the diaphragm is capable of vibrating between a positive maximum amplitude and a negative maximum amplitude as designed, and the initial position of the diaphragm is an intermediate position between the positive maximum amplitude and the negative maximum amplitude. When the vibration balance position of the diaphragm is coincident with the initial position of the diaphragm, the diaphragm can work at the maximum amplitude during actual work, the performance of the loudspeaker can be best, and the output sound pressure level is larger. The maximum amplitude of the diaphragm at this time is the distance between the initial position and the maximum amplitude of the forward direction (or between the initial position and the maximum amplitude of the forward direction).
When the driving voltage of the speaker is large, the vibration balance position (also called as dynamic vibration center, dynamic balance position) of the speaker diaphragm may shift from the initial position. Fig. 4(a) shows the vibration balance position of the diaphragm above the initial position (i.e., the positive z-direction), and when the diaphragm vibrates upward and the displacement of the diaphragm reaches the maximum amplitude, the Smart PA protection function of the speaker starts to function to limit the displacement of the upward vibration of the diaphragm, where the actual vibration amplitude of the diaphragm is the distance between the vibration balance position and the maximum positive amplitude. When the vibrating diaphragm works, the vibrating diaphragm symmetrically vibrates upwards and downwards by taking the vibration balance position as the center. Therefore, when the vibration balance position of the diaphragm deviates from the initial position upwards, the distance of the downward vibration of the diaphragm cannot reach the negative maximum amplitude, so that the downward safe vibration space of the diaphragm is not fully utilized, and the sound pressure level output by the loudspeaker is smaller; similarly, fig. 4(B) shows that the dynamic position of the diaphragm is below the initial position (i.e., negative in the z-direction), when the amplitude of the downward vibration of the diaphragm reaches the negative maximum amplitude, the Smart PA protection of the speaker is turned on, the upward safe vibration space of the diaphragm is not fully utilized, and the output sound pressure level is low. Fig. 4(C) shows a case where the vibration balance position of the diaphragm is not shifted from the initial position, where the upward and downward amplitudes of the diaphragm substantially reach the maximum amplitude at the same time, and a Smart PA protection function is triggered, so that both the upward and downward safe vibration spaces can be fully utilized, and a larger sound pressure level can be output.
In order to ensure that the loudspeaker can output a larger sound pressure level, when the vibration balance position of the diaphragm of the loudspeaker is detected to deviate from the initial position, the vibration balance position of the diaphragm needs to be corrected, so that the vibration balance position of the diaphragm is basically overlapped with the initial position, and at this time, the working state of the diaphragm can reach the state shown in fig. 4 (C).
Fig. 9 illustrates a schematic diagram of a method for adjusting a vibration balance position of a loudspeaker diaphragm according to an embodiment of the present invention:
901: obtaining the displacement d of the vibration balance position of the loudspeaker diaphragm from the initial positionoffset；
When the loudspeaker works, the vibrating diaphragm vibrates upwards and downwards by taking the vibration balance position of the vibrating diaphragm as the center. The initial position of the diaphragm refers to the equilibrium position of the diaphragm when it is operating at maximum amplitude. The maximum diaphragm may be a vibration amplitude at which the diaphragm vibrates upward and downward in a safety space (as shown in fig. 3, the safety space may be a space formed between 301 and 303) without contacting other objects. Displacement doffsetThe displacement is the displacement of the vibration balance position of the vibrating diaphragm deviating from the initial position when the loudspeaker works. When the displacement d isoffsetWhen the vibration balance position is not zero, the vibration balance position of the diaphragm deviates from the initial position, and the vibration balance position of the diaphragm needs to be corrected. The displacement d may be setoffsetAnd when the vibration balance position of the diaphragm exceeds a preset value, correcting the vibration balance position of the diaphragm. For example, the preset value may be 0.05 mm. As to how to obtain the displacement doffsetThe method of (a) is described below.
902: inputting a DC bias current i to a voice coil of the loudspeaker according to the displacement d-offsetoffset，
To calibrate the vibration balance position of the loudspeaker diaphragm to the initial position.
Introducing direct current i to voice coil of loudspeakeroffsetThen, the voice coil generates a magnetic force FoffsetThe magnetic force acts on the diaphragm to offset the deviation d of the vibration balance position of the diaphragm relative to the initial positionoffsetWherein the offset doffsetMagnetic force FoffsetAnd current ioffsetThe following relationships exist:
Foffset＝-Kms*doffet(1)
wherein, KmsB1 are the loudspeaker equivalent stiffness coefficient and the magnetic force factor, respectively, as known quantities.
Therefore, the offset d is obtainedoffsetThen, the bias current i can be calculatedoffsetThe size of (2).
In some embodiments, the temperature at which the speaker operates may be further detected, and based on this temperature, the bias current i may be more accurately determinedoffset. For example, according to steps 901 and 902, the bias current i has been determinedoffset1.0A. When the temperature of the loudspeaker is detected to be 40 ℃, correcting the bias current to be 1.01A; the bias current was 1.05A at a speaker temperature of 50 degrees celsius.
Referring to fig. 4(a), the vibration balance position of the diaphragm is deviated from the initial position to obtain the deviation doffsetApproximately 0.5 mm. Applying a bias current i to the voice coiloffset。ioffsetCan be calculated by the above equations (1) and (2). Applying a bias current ioffsetThen, the voice coil generates a magnetic force FoffsetAnd the magnetic force acts on the diaphragm, so that the vibration balance position of the diaphragm moves downwards to return to the initial position. The principle of adjusting the vibration balance position of the diaphragm to move downwards as shown in fig. 4(B) is similar.
The following describes a method for obtaining a diaphragm offset d according to an embodiment of the present inventionoffsetThe method of (1).
As shown in fig. 3, a flat capacitor may be formed between a diaphragm 302 and a front cover 301 of the speaker. The front cover 101 is generally made of metal. Therefore, the front cover 101 may constitute a fixed plate of the panel capacitor. If the front cover 101 is made of a non-metallic material, a conductive material layer may be disposed on the front cover 101, and the conductive material layer may be attached to the lower surface of the front cover 101. The front cover 101 is not necessarily made of a metal material, and a part of the front cover 101 is made of a metal material.
If the diaphragm is a plastic diaphragm, such as polypropylene, or the diaphragm is a synthetic fiber material, a conductive material layer can be arranged on the diaphragm. The diaphragm can also be made of metal. Thus, the diaphragm may constitute a movable plate of a plate capacitor. The fixed plate and the movable plate are opposite to each other to form a capacitor.
In other embodiments provided by the present invention, the flexible circuit board 104 may also be fixed on one side of the diaphragm 103, a conductive material layer is disposed in the middle of the flexible circuit board 104, and the flexible circuit board 104 and the front cover 101 form a capacitor.
As shown in fig. 3, when the speaker operates, the distance d between the diaphragm and the front cover varies with the vibration of the diaphragm. The corresponding distance change can be calculated from its dynamic capacitance C. Therefore, by monitoring the capacitance in real time, the dynamic position of the diaphragm in the z-direction can be monitored. The offset of the vibration balance position in the z-direction can be calculated from the difference of the upper and lower amplitudes.
Where, is the dielectric constant, S is the effective area of the parallel plate capacitor, and d is the distance between the plates.
Assuming that the diaphragm vibrates upward, the distance between the electrode plates is calculated as dz1(ii) a When the diaphragm vibrates downwards, the distance between the polar plates is dz2. Then there are:
Zmax+＝d1-dz1；Zmax-＝d1-dz2
therefore, the vibration balance position of the diaphragm is shifted by a distance d from the initial positionoffsetComprises the following steps:
in the formula, Zmax+Is the maximum displacement of the diaphragm in the positive Z-direction during operation, Zmax-The maximum displacement of the diaphragm in the negative z-direction during operation.
The embodiment of the invention provides another method for obtaining the offset d of the diaphragmoffsetThe method of (1). Fixing a magnetic sensor on a diaphragm, the magnetic sensorThe sensor can measure and collect magnetic induction intensity. The magnetic sensor may be a Hall (Hall) sensor. Since the magnetic induction is related to the position of the diaphragm during vibration, the position of the diaphragm during vibration can be obtained by the magnetic induction.
Obtaining the offset d of the diaphragmoffsetThen, a DC bias current i is input to the voice coil of the loudspeakeroffsetAnd calibrating the vibration balance position of the loudspeaker diaphragm, and calibrating the vibration balance position of the diaphragm to an initial position. When the vibrating diaphragm works, the initial position is used as vibration balance, and the upward vibration and the downward vibration can reach the maximum vibrating diaphragm. The loudspeaker can therefore perform optimally.
The embodiment of the invention provides a method for measuring the capacitance C of a capacitor formed by a vibrating diaphragm and a front cover. The circuit for testing the capacitance C is shown in fig. 5. Wherein the capacitor C is formed by the diaphragm and the front cover. The circuit may be integrated into a chip of SmartPA or may be a separate circuit or chip. The ADC in fig. 5 is an analog-to-digital converter.
The voltage value Uo is proportional to the measured capacitance value C
If j ω RfCf> 1, then
I.e. the voltage value U0Is proportional to the measured capacitance value C.
Fig. 6 is a schematic structural diagram of a capacitance data collector provided in an embodiment of the present invention. The capacitance measuring circuit in fig. 6 is shown in fig. 5. In particular, voltage UoAnd finally obtaining the capacitor C to be detected through the processing of an alternating current amplifier, a full-wave rectifying circuit, a low-pass filter and an A/D conversion circuit. Measured capacitance C is represented by C in FIG. 6xAnd (4) showing.
Fig. 7 shows a circuit for detecting amplitude of a diaphragm according to an embodiment of the present invention. Acquiring the measured capacitor C through a capacitance data acquisition unitxThen, the vibration film meter is vibrated by a vibrating filmA calculating module for calculating the offset d of the diaphragmoffset。
The embodiment of the invention also provides a PA chip 802. As shown in fig. 8, 801 denotes a capacitor formed by the diaphragm and the front cover, 803 denotes an adder, and 804 denotes an amplifier. The PA chip comprises a diaphragm amplitude detection circuit, a diaphragm position control circuit, a signal and gain control circuit and the like. One end of the PA chip is connected with the voice coil, and the other end of the PA chip is connected with a capacitor formed by the vibrating diaphragm and the front cover. Amplitude d and diaphragm offset d of diaphragm detected by diaphragm and diaphragm detection circuitoffset. Wherein the amplitude d can also be used to send to an algorithm module which can determine the bias current i more accurately, depending on the detected diaphragm d, and on the detected operating temperature of the loudspeakeroffset. For example, when the temperature of the speaker is 40 degrees celsius, the bias current is 1.0A; the bias current was 1.1A at a speaker temperature of 50 degrees celsius. The information sent to the algorithm module may also include d alone or in combinationoffset. Offset d of diaphragmoffsetIs sent to the diaphragm position control circuit. A diaphragm position control circuit for calculating the bias current i by the methodoffset. Offset current ioffsetAnd information such as signals, gains and the like is sent to the voice coil, and the vibration balance position of the vibrating diaphragm is controlled through the voice coil. Wherein the signal may be an audio signal; the gain may vary the amplitude of the diaphragm.
Claims (8)
1. A method of adjusting a vibration balance position of a diaphragm, the method comprising:
obtaining the displacement of the vibration balance position of a vibrating diaphragm of a loudspeaker deviating from an initial position, wherein when the vibrating diaphragm works, the vibrating diaphragm takes the vibration balance position as the vibration balance position, and when the vibrating diaphragm takes the initial position as the vibration balance position, the vibrating diaphragm vibrates with a preset maximum amplitude;
inputting a direct current bias current to a voice coil of the loudspeaker according to the displacement so as to calibrate the vibration balance position of the diaphragm to the initial position, wherein the voice coil is positioned on one side of the diaphragm and vibrates with the diaphragm;
the obtaining of the displacement of the vibration balance position of the diaphragm of the speaker from the initial position specifically includes:
detecting a capacitance value of a capacitor formed between a front cover of the speaker and the diaphragm;
calculating the displacement according to the capacitance value;
according to the displacement d by the following formulaoffsetCalculating the DC bias current ioffset：
Wherein, KmsBl is a magnetic force factor of the voice coil and the magnetic circuit assembly, which is an equivalent stiffness coefficient of the speaker.
2. The method according to claim 1, wherein the obtaining of the displacement amount of the vibration balance position of the diaphragm of the loudspeaker from the initial position is specifically:
arranging a magnetic induction device on the vibrating diaphragm, measuring the magnetic induction intensity in the loudspeaker through the magnetic induction device, and calculating the vibration displacement of the vibrating diaphragm;
and calculating the displacement of the vibration balance position of the vibrating diaphragm from the initial position according to the vibration displacement of the vibrating diaphragm.
3. The method of claim 2, wherein the magnetic induction device is a hall sensor.
4. The method according to any one of claims 1-3, further comprising:
detecting the temperature of the loudspeaker during working;
and determining the direct current bias current input to the voice coil of the loudspeaker according to the displacement and the temperature of the loudspeaker during working.
5. The utility model provides a loudspeaker, its characterized in that, loudspeaker includes from last to down in proper order: the front cover, the vibration component and the magnetic circuit component; the vibration assembly comprises a voice coil and a vibrating diaphragm, wherein the voice coil is positioned on one side of the vibrating diaphragm and vibrates along with the vibrating diaphragm;
the loudspeaker also comprises a diaphragm amplitude detection circuit, wherein the diaphragm amplitude detection circuit is used for acquiring the displacement of the vibration balance position of the diaphragm from the initial position, the diaphragm uses the vibration balance position as the vibration balance position when the diaphragm works, and the diaphragm vibrates with the preset maximum amplitude when the diaphragm uses the initial position as the vibration balance position;
the loudspeaker also comprises a diaphragm position control circuit, wherein the diaphragm position control circuit is used for inputting direct current bias current to a voice coil of the loudspeaker according to the displacement detected by the diaphragm detection circuit so as to calibrate the vibration balance position of the diaphragm to the initial position;
the front cover is made of metal materials, or a conductive material layer is arranged on the front cover;
the vibrating diaphragm is made of metal materials, or a conductive material layer is arranged on the vibrating diaphragm;
the vibration diaphragm amplitude detection circuit is used for detecting the capacitance value of a capacitor formed between the front cover and the vibration diaphragm to obtain the displacement of the vibration balance position of the vibration diaphragm deviating from the initial position;
according to the displacement d by the following formulaoffsetCalculating the DC bias current ioffset：
Wherein, KmsBl is a magnetic force factor of the voice coil and the magnetic circuit assembly, which is an equivalent stiffness coefficient of the speaker.
6. The loudspeaker of claim 5, wherein:
a magnetic induction device is arranged on the vibrating diaphragm;
the vibration diaphragm amplitude detection circuit measures the magnetic induction intensity in the loudspeaker through the magnetic induction device, and obtains the vibration balance position of the vibration diaphragm deviates from the displacement of the initial position.
7. The loudspeaker of claim 6, wherein the magnetic induction device is a Hall sensor.
8. The loudspeaker according to any one of claims 5 to 7, wherein the loudspeaker comprises a temperature compensation circuit;
the temperature compensation circuit is used for detecting the temperature of the loudspeaker during working;
and the diaphragm position control circuit determines the direct current bias current input to the voice coil of the loudspeaker according to the displacement and the temperature of the loudspeaker during working.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611153804 | 2016-12-14 | ||
| CN2016111538040 | 2016-12-14 | ||
| PCT/CN2016/111347 WO2018107512A1 (en) | 2016-12-14 | 2016-12-21 | Method for adjusting diaphragm vibration balancing position and speaker |
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| Publication Number | Publication Date |
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| CN109997372A CN109997372A (en) | 2019-07-09 |
| CN109997372B true CN109997372B (en) | 2020-10-23 |
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| CN201680091207.1A Active CN109997372B (en) | 2016-12-14 | 2016-12-21 | Method for adjusting vibration balance position of vibrating diaphragm and loudspeaker |
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| Country | Link |
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| CN (1) | CN109997372B (en) |
| WO (1) | WO2018107512A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112019987A (en) * | 2019-05-31 | 2020-12-01 | 华为技术有限公司 | Speaker device and output adjusting method for speaker |
| CN111556385A (en) * | 2020-05-12 | 2020-08-18 | 深圳市信维声学科技有限公司 | Micro speaker and amplitude adjusting method thereof |
| CN111885470B (en) * | 2020-06-16 | 2021-07-27 | 歌尔微电子有限公司 | Capacitive micro-electro-mechanical system microphone, microphone monomer and electronic equipment |
| WO2022000335A1 (en) * | 2020-06-30 | 2022-01-06 | 深圳市大疆创新科技有限公司 | Audio processing method and apparatus, and electronic device |
| CN112291685B (en) * | 2020-10-29 | 2022-04-12 | 维沃移动通信有限公司 | Method and device for balancing loudspeaker vibration, loudspeaker and storage medium |
| CN114845224A (en) * | 2020-11-26 | 2022-08-02 | 广东小天才科技有限公司 | Method and device for adjusting position of loudspeaker diaphragm and storage medium |
| CN112954549B (en) * | 2021-02-25 | 2022-09-09 | 歌尔科技有限公司 | Sound effect control method and device, sound box equipment and storage medium |
| CN113132868A (en) * | 2021-04-23 | 2021-07-16 | 维沃移动通信有限公司 | Speaker, amplitude adjusting method, amplitude adjusting device, and electronic apparatus |
| CN113132850B (en) * | 2021-04-28 | 2023-05-26 | Oppo广东移动通信有限公司 | Speaker parameter configuration method and related device |
| CN113691905B (en) * | 2021-08-05 | 2024-02-27 | 维沃移动通信有限公司 | Air pressure adjusting method and device, electronic equipment and storage medium |
| CN113676807B (en) * | 2021-08-05 | 2024-04-19 | 维沃移动通信有限公司 | Earphone and electronic equipment assembly |
| CN114979853A (en) * | 2022-05-13 | 2022-08-30 | 维沃移动通信有限公司 | Mobile terminal and playback control method |
| CN116896713B (en) * | 2023-09-04 | 2023-12-05 | 立臻精密智造(昆山)有限公司 | Device and method for determining height of loudspeaker diaphragm |
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| WO2018107512A1 (en) | 2018-06-21 |
| CN109997372A (en) | 2019-07-09 |
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