CN204559886U - Loudspeaker assembly resonance frequency measuring system - Google Patents
Loudspeaker assembly resonance frequency measuring system Download PDFInfo
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- CN204559886U CN204559886U CN201520292814.7U CN201520292814U CN204559886U CN 204559886 U CN204559886 U CN 204559886U CN 201520292814 U CN201520292814 U CN 201520292814U CN 204559886 U CN204559886 U CN 204559886U
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- 238000012360 testing method Methods 0.000 claims description 4
- 238000012545 processing Methods 0.000 claims description 3
- 238000007405 data analysis Methods 0.000 abstract 1
- 238000013480 data collection Methods 0.000 abstract 1
- 239000000306 component Substances 0.000 description 30
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Abstract
The utility model patent proposes a kind of loudspeaker assembly resonance frequency measuring system.The measuring system that the utility model patent proposes comprises data collection and analysis processor, power amplifier, excitation sound source, tested speaker parts, laser displacement sensor, microphone, operative employee's station and excitation workbench and frock clamp etc.Excitation sound source is arranged on excitation table surface, and excitation workbench is placed on below operative employee's station, and the excitation sound source of below faces the tested speaker parts of top; Laser displacement sensor and microphone are fixed on the multiple bay of top, multifunctional measuring support can at operative employee's station table top superjacent air space up and down, front and back and left and right movement arbitrarily.The utility model accurately and easily can measure the resonance frequency of diffuser (vibrating diaphragm) and centring disk.
Description
Technical Field
The utility model belongs to the electroacoustic technology application field relates to speaker part resonant frequency measurement system. The system can be used for measuring the resonance frequency of the loudspeaker component (comprising a cone or a vibrating diaphragm and a centering disk), and can be widely applied to the quality inspection (control) of the loudspeaker component and the design and research and development of the loudspeaker.
Background
Significance of the measurement of the resonant frequency of the loudspeaker component:
the loudspeaker is an electric power sound coupling system and mainly comprises a magnetic circuit system, a vibration system and an acoustic load. The cone and the centering disk of the loudspeaker are core components of a loudspeaker vibration system, and the resonance frequency is one of important technical indexes of the loudspeaker, and the technical indexes play a vital role in the overall performance of the loudspeaker.
The prior art and methods:
the traditional main method for testing the resonant frequency of the loudspeaker diaphragm is an indirect testing method. The method comprises the steps of fixing a tested vibrating diaphragm right above an excitation sound source, and driving a loudspeaker by using a sine signal frequency sweeping signal to enable the tested vibrating diaphragm to vibrate along with the sine signal frequency sweeping signal. The air cavity formed by the vibrating diaphragm and the excitation sound source generates a feedback effect on the excitation sound source, so that the current of the driving loudspeaker changes, and the resonant frequency of the tested vibrating diaphragm can be calculated by measuring the current change. The method has obvious limitations, can only measure the vibrating diaphragm with larger resonance Q value, larger size and small mass, and has higher requirements on the loudspeaker for excitation, and the resonance frequency of the loudspeaker is required to be far less than that of the vibrating diaphragm to be measured. Thus, there are many problems with the versatility and accuracy of this method.
With the development of electronic information technology, some methods for measuring the resonant frequency of a loudspeaker diaphragm by using a direct method have appeared. Chinese patent application publications 201310157000.8 and 201420149091.0 disclose a method of measuring the resonant frequency of a loudspeaker diaphragm using a direct method. The method adopts a laser displacement sensor to directly read the displacement signal of the tested loudspeaker diaphragm and directly calculates the resonant frequency of the tested diaphragm according to the displacement signal. However, in this method, the resonance frequency of the excitation sound source itself and the influence of the cavity formed by the diaphragm to be measured and the excitation sound source on the measurement result are not fully considered, and therefore, a large measurement error is generated for a micro speaker with a small size or a diaphragm with a resonance frequency closer to the resonance frequency of the excitation sound source.
In addition, since the resonant frequencies of the loudspeaker diaphragms are different under different amplitudes, that is, the diaphragms are excited by different forces to obtain different resonant frequencies, when the method and the conventional equipment are used for measurement, the vibration amplitude of the measured diaphragm cannot be set, and the results obtained by different users even if the same equipment of the same type is used for measurement are different, which often results in contradiction between the supplier and the buyer of the diaphragms.
The measurement of the resonant frequency of the cone and the centering disk of the loudspeaker by the above measurement method has similar problems.
In order to solve the technical problem, the utility model provides a loudspeaker part (including cone (or vibrating diaphragm) and centering disk) resonant frequency measurement method and system adopts frequency response compensation technique and appoints the amplitude through the ration, can effectually solve the drawback that traditional measuring method exists, and then can obtain reliable, accurate measuring result.
SUMMERY OF THE UTILITY MODEL
To the above problem, the utility model provides a measurement and measurement system of speaker part resonant frequency.
The utility model provides a measurement system of speaker part resonant frequency can accurately measure the resonant frequency of speaker cone (vibrating diaphragm) and centering support piece.
The utility model provides a technical scheme that technical problem adopted does:
the utility model provides a loudspeaker component resonant frequency measurement system, including loudspeaker component resonant frequency measurement system, characterized in that this system includes data acquisition analysis processor, power amplifier, excitation sound source, laser displacement sensor, microphone, excitation workstation, operation workstation and combination frock clamp; at least one set of combined tool clamp is arranged on the table surface of the operating workbench in an embedded mode; the exciting sound source is arranged on the table surface of the exciting workbench, the exciting workbench is arranged below the operating workbench, and the exciting sound source on the exciting workbench is directly opposite to the tested loudspeaker component clamped in the combined tool clamp; the laser displacement sensor and the microphone are fixed on a multifunctional measuring support which moves up and down (in the Z-axis direction), the multifunctional measuring support is fixed on a double-shaft sliding table, the double-shaft sliding table is arranged in a guide rail above the operating workbench, and the double-shaft sliding table moves in the guide rail at any position of front and back (in the X-axis direction) and left and right (in the Y-axis direction);
the data acquisition and analysis processor is respectively connected with a power amplifier, a laser displacement sensor and a microphone, the power amplifier is connected with an excitation sound source, and the laser displacement sensor and the microphone face a tested loudspeaker component during measurement;
the data acquisition and analysis processor has the functions of: the device is responsible for generating an excitation signal, and collecting, analyzing, processing, storing and displaying a signal obtained by measurement;
the power amplifier has the functions of: and amplifying the excitation signal sent by the data acquisition and analysis processor and then pushing the excitation loudspeaker to vibrate.
The laser displacement sensor has the functions of: and displacement signals of the tested component are collected and sent to a data acquisition analysis processor.
The microphone has the functions of: when frequency response calibration is carried out, acoustic signals emitted by the exciting loudspeaker are picked up and sent to the data acquisition and analysis processor.
The tested loudspeaker component comprises a loudspeaker cone or a diaphragm and a centering support sheet.
The excitation workbench is placed below the operation workbench, the table surfaces of the two workbenches are parallel to each other, a gap is reserved, an excitation sound source arranged on the excitation workbench below faces a tested loudspeaker component arranged above the operation workbench and clamped in the combined tool clamp, a certain gap exists between the excitation sound source and the tested loudspeaker component, air is open between the excitation sound source and the tested loudspeaker component, and a cavity is not formed.
The excitation sound source is one or more different types of loudspeakers; the combined tool clamp consists of a series of rings with different radiuses, and the rings can be combined with each other for use; a plurality of sets of combined tool fixtures are arranged on the table surface of the operating workbench.
The utility model has the advantages that: the method can conveniently and quickly measure the resonant frequency of the loudspeaker component including the cone (or the vibrating diaphragm) and the centering support, and the obtained measurement result is more reliable and accurate due to the adoption of frequency response compensation and excitation signal size adjustment.
Drawings
FIG. 1 is a block diagram of a measurement system.
FIG. 2 is a cross-sectional view of a measurement system tool.
Fig. 3 is a view of a measurement system tool.
Fig. 4 is a sectional view of the tool holder.
FIG. 5 is a time domain waveform diagram of a test excitation signal.
FIG. 6 is a time domain waveform diagram of an excitation signal after frequency response compensation.
Fig. 7 frequency response of the measurement environment before and after frequency response compensation.
Fig. 8 is a graph of measurement results.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1, the utility model comprises: the device comprises a data acquisition and analysis processor (1), a power amplifier (2), an excitation sound source (loudspeaker) (3), a tested loudspeaker component (4), a laser displacement sensor (5), a microphone (6), an operation workbench (7) and an excitation workbench (8).
A combined measuring clamp is arranged on the table top of the operating workbench (7) in an embedded mode, and the combined measuring clamp can be used for fixing tested loudspeaker components with different sizes; the excitation sound source (3) is arranged on the surface of an excitation workbench (8), the excitation workbench (8) is arranged below the operation workbench (7) (the surfaces of the two workbenches are parallel to each other, and are not connected with each other except the same ground), and the excitation sound source (3) below is directly opposite to the tested loudspeaker component (4) above; the laser displacement sensor (5) and the microphone (6) are fixed on the multifunctional measuring bracket, and the multifunctional measuring bracket can move up and down (in the Z-axis direction); the multifunctional measuring bracket is fixed on the double-shaft sliding table, and the double-shaft sliding table can move freely back and forth (in the X-axis direction) and left and right (in the Y-axis direction) in the space above the table top of the operating table (7) through a guide rail fixed above the operating table (7);
the working process of the measuring system is as follows: an excitation signal generated by the data acquisition and analysis processor (1) is amplified by the power amplifier (2) and then is sent to the excitation sound source (3), and sound waves emitted by the excitation sound source (3) push the tested loudspeaker component (4) to generate vibration; the laser displacement sensor (5) picks up the vibration displacement signal of the tested loudspeaker component and sends the vibration displacement signal back to the data acquisition and analysis processor (1). The data acquisition and analysis processor (1) processes the displacement signals and displays and stores the processing result.
In order to reduce the performance requirement on an exciting sound source (loudspeaker) (3), eliminate the adverse effect of the exciting sound source (3) and the measuring environment on the vibration of a tested loudspeaker component (4) and improve the measuring accuracy of the system, before the system is formally measured, the system must firstly perform frequency response compensation on the acoustic environment consisting of the exciting sound source (3), the tested loudspeaker component (4), an operating workbench (7), an exciting workbench (8) and the surrounding air thereof, so that the tested loudspeaker component is basically stressed the same at any frequency point in a measuring frequency band under the excitation of the exciting sound source.
The frequency response compensation process is as follows:
an excitation signal generated by the data acquisition and analysis processor (1) is amplified by the power amplifier (2) and then is sent to the excitation sound source (3), and sound waves emitted by the excitation sound source (3) push the tested loudspeaker component (4) to generate vibration; meanwhile, the microphone (6) is aligned with the center position of the tested part (4), and the frequency response of the acoustic environment comprising the exciting sound source (3), the tested loudspeaker part (4), the operating workbench (7), the exciting workbench (8) and the surrounding air at the moment is calculated through the collected acoustic signal and the exciting signal.
The frequency response is calculated by the formula
WhereinHp(f)Is a frequency domain representation of the frequency response, and P (f) is a frequency domain table of the acoustic signals acquired by the microphoneU (f) is a frequency domain representation of the excitation signal.
After obtaining the frequency response, the frequency response is calculated by the formulaAnd calculating the excitation signal after the frequency response compensation, and taking the signal as the excitation signal of the excitation sound source. Wherein,u’(t)for the frequency response compensated excitation signal,u(t)for the excitation signal before frequency response compensation, a convolution is indicated,Hp(f)for the frequency response calculated from (1)， -1 FIs an inverse fourier transform.
And the frequency compensation step is finished.
Fig. 6 shows the compensated excitation signal. Fig. 7 is a frequency response of an acoustic measurement environment before and after frequency response compensation.
After the frequency response compensation is completed and before formal measurement is carried out, the system needs to adjust the magnitude of the excitation signal. The current amplitude is calculated by the displacement signal of the set picked up by the laser displacement sensor (5), and then the current amplitude is compared with the target amplitude to adjust the size of the excitation signal. If the current amplitude is larger than the target amplitude, reducing the size of the excitation signal; otherwise, the opposite is true. Finally, the amplitude of the tested loudspeaker component reaches a target value.
The excitation signal size adjustment process is as follows:
an excitation signal generated by the data acquisition and analysis processor (1) is amplified by the power amplifier (2) and then is sent to the excitation sound source (3), and sound waves emitted by the excitation sound source (3) push the tested loudspeaker component (4) to generate vibration; meanwhile, under the condition that the gain of the power amplifier (2) is not changed, the laser displacement sensor (5) is aligned to the edge position of the tested part (4), and the size of the excitation signal is adjusted through the collected displacement signal, namely: if the amplitude calculated from the displacement signal exceeds the target amplitude, the magnitude of the excitation signal is decreased, and vice versa.
The amplitude is calculated from the displacement signal in a manner of (Xmax-Xmin)/2, where Xmax is the maximum value of the displacement signal and Xmin is the minimum value of the displacement signal.
Because the amplitude of the loudspeaker component to be measured is calculated through the maximum value and the minimum value of the displacement signal, the laser displacement sensor does not need to be calibrated before measurement every time, and only the maximum value and the minimum value of the displacement signal are required to be within the measuring range of the laser displacement sensor.
Thus, the amplitude adjustment step is completed.
After the frequency response compensation and amplitude adjustment processes are finished, the excitation sound source (3) is pushed through the adjusted excitation signal, the vibration displacement signal of the tested part (4) is picked up by using the laser displacement sensor (5), and the relation between the signal and the sine sweep frequency signal, namely the formulaAnd calculating the frequency response of the displacement signal, and finding out the frequency corresponding to the maximum value of the frequency response, namely the resonant frequency of the tested component (as shown in fig. 8). In the above formulaHx(f)Is a frequency domain representation of the frequency response, x (f) is a frequency domain representation of the displacement signal acquired by the laser displacement sensor, and u (f) is a frequency domain representation of the excitation signal.
Under the premise that the excitation signal is determined and the gain of the power amplifier is not changed, the amplitudes generated by different tested loudspeaker components are different. Therefore, the system also adds a feedback correction function, namely: when the system detects that the amplitude of the tested loudspeaker component does not reach the specified amplitude through the displacement signal, the amplitude calibration function is automatically started, and the resonant frequency of the tested loudspeaker component is measured again.
Finally, it should be noted that: the above embodiments are only used to illustrate the present invention and not to limit the technical solutions described in the present invention; thus, although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted; all technical solutions and modifications without departing from the spirit and scope of the present invention should be covered by the claims of the present invention.
Claims (4)
1. A loudspeaker part resonant frequency measuring system is characterized by comprising a data acquisition and analysis processor, a power amplifier, an excitation sound source, a laser displacement sensor, a microphone, an excitation workbench, an operation workbench and a combined tool clamp; at least one set of combined tool clamp is arranged on the table surface of the operating workbench in an embedded mode; the exciting sound source is arranged on the table surface of the exciting workbench, the exciting workbench is arranged below the operating workbench, and the exciting sound source on the exciting workbench is directly opposite to the tested loudspeaker component clamped in the combined tool clamp; the laser displacement sensor and the microphone are fixed on a multifunctional measuring support which moves up and down, the multifunctional measuring support is fixed on a double-shaft sliding table, the double-shaft sliding table is arranged in a guide rail above the operating workbench, and the double-shaft sliding table moves in the guide rail at any position of front, back, left and right;
the data acquisition and analysis processor is respectively connected with a power amplifier, a laser displacement sensor, a microphone, a power amplifier and an exciter
The sound source is connected, and the laser displacement sensor and the microphone face the tested loudspeaker component during measurement;
the data acquisition and analysis processor has the functions of: the device is responsible for generating an excitation signal, and collecting, analyzing, processing, storing and displaying a signal obtained by measurement;
the power amplifier has the functions of: amplifying the excitation signal sent by the data acquisition and analysis processor and then pushing the excitation loudspeaker to vibrate;
the laser displacement sensor has the functions of: collecting displacement signals of a tested component and delivering the displacement signals to a data acquisition analysis processor;
the microphone has the functions of: when frequency response calibration is carried out, acoustic signals emitted by the exciting loudspeaker are picked up and sent to the data acquisition and analysis processor.
2. A loudspeaker component resonance frequency measurement system according to claim 1, wherein the loudspeaker component under test comprises a loudspeaker cone or diaphragm and a centring disk.
3. The system of claim 1, wherein the excitation stage is disposed under the operation stage, the two stages are parallel to each other with a gap, the excitation source disposed under the excitation stage faces the tested speaker component disposed above the operation stage and clamped in the combined fixture, and a gap is formed between the excitation source and the tested speaker component, and air is open between the excitation source and the tested speaker component without forming a cavity.
4. A loudspeaker component resonance frequency measurement system according to claim 1, wherein the excitation sound source is one or more different types of loudspeakers; the combined tool clamp consists of a series of rings with different radiuses, and the rings can be combined with each other for use; a plurality of sets of combined tool fixtures are arranged on the table surface of the operating workbench.
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| CN201520292814.7U CN204559886U (en) | 2015-05-08 | 2015-05-08 | Loudspeaker assembly resonance frequency measuring system |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107631795A (en) * | 2017-09-12 | 2018-01-26 | 许睿 | A kind of Insect Acoustical Signals measurement apparatus and measuring method |
| CN107682803A (en) * | 2017-11-22 | 2018-02-09 | 江苏鹏美电声器材有限公司 | A kind of analog detection method of diffuser resonant frequency |
| CN107959916A (en) * | 2017-11-22 | 2018-04-24 | 江苏鹏美电声器材有限公司 | A kind of diffuser detects gauge |
| CN108156571A (en) * | 2016-12-02 | 2018-06-12 | 西格玛艾尔科技股份有限公司 | Light and small shape loud speaker cone paper resonant frequency check device |
-
2015
- 2015-05-08 CN CN201520292814.7U patent/CN204559886U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108156571A (en) * | 2016-12-02 | 2018-06-12 | 西格玛艾尔科技股份有限公司 | Light and small shape loud speaker cone paper resonant frequency check device |
| CN107631795A (en) * | 2017-09-12 | 2018-01-26 | 许睿 | A kind of Insect Acoustical Signals measurement apparatus and measuring method |
| CN107682803A (en) * | 2017-11-22 | 2018-02-09 | 江苏鹏美电声器材有限公司 | A kind of analog detection method of diffuser resonant frequency |
| CN107959916A (en) * | 2017-11-22 | 2018-04-24 | 江苏鹏美电声器材有限公司 | A kind of diffuser detects gauge |
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