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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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 electroacoustic techniques application, relates to loudspeaker assembly resonance frequency measuring system.Adopt native system can measure the resonance frequency of loudspeaker assembly (comprising cone or vibrating diaphragm and centring disk), the quality inspection (control) of loudspeaker assembly and loudspeaker design and research and development can be widely used in.
Background technology
The meaning that loudspeaker assembly resonance frequency is measured:
Loud speaker is the system of an electric power acoustical coupling, primarily of magnetic circuit system, vibrational system and acoustic load three part composition.The cone of loud speaker and centring disk are the core components of speaker vibration system, and resonance frequency is one of its important technology index, and the overall performance of this technical indicator to loud speaker plays vital effect.
Existing techniques and methods:
The main method of traditional test loudspeaker vibrating diaphragm resonant frequency is indirectly testing method.First tested vibrating diaphragm is fixed on directly over excitation sound source by the method, drives loud speaker that tested vibrating diaphragm is vibrated thereupon by sinusoidal signal swept-frequency signal.The air cavity formed by vibrating diaphragm and excitation sound source produces feedback effect to excitation sound source, and then causes driving the electric current of loud speaker to change, and can calculate the resonance frequency of tested vibrating diaphragm by measuring this curent change.The method has limitation clearly, it is merely able to, and measurement resonant Q value is comparatively large, size is comparatively large and the vibrating diaphragm that quality is neither big nor small, and have higher requirements to the loud speaker of excitation, it requires that the resonance frequency of this loud speaker must much smaller than the resonance frequency of tested vibrating diaphragm.Therefore, there are problems in the versatility of the method and accuracy.
Along with the development of electronic information technology, also occur that part uses direct method to measure the method for diaphragm of loudspeaker resonance frequency.The open book 201310157000.8 and 201420149091.0 of Chinese patent application discloses a kind of method adopting direct method to measure the resonance frequency of the diaphragm of loudspeaker.The method adopts laser displacement sensor directly to read the displacement signal of tested speaker vibrating diaphragm, and is directly calculated the resonance frequency of tested vibrating diaphragm by this displacement signal.But, the method due to do not take into full account excitation sound source own resonance frequency and tested vibrating diaphragm with excitation sound source form the impact of cavity on measurement result, therefore, all larger measure error can be produced for the less Microspeaker of size or resonance frequency and the comparatively close vibrating diaphragm of excitation sound source resonance frequency.
In addition, because the resonance frequency of the diaphragm of loudspeaker under various amplitude is different, namely the power of different size is adopted to encourage vibrating diaphragm can obtain different resonance frequencys, when using said method and legacy equipment measures, because the Oscillation Amplitude of tested vibrating diaphragm cannot be set, even if the result also non-equal that different user uses the device measuring of the same race of same model to obtain, often cause producing contradiction between vibrating diaphragm supplier and buying side.
Also there is Similar Problems in the measurement of above-mentioned method of measurement to the resonance frequency of diffuser and centring disk.
In order to solve the problems of the technologies described above, loudspeaker assembly (comprising cone (or vibrating diaphragm) and the centring disk) resonant frequency measurement method that the utility model proposes and system, adopt compensating for frequency response technology and pass through quantitatively to specify amplitude, effectively can solve the drawback existing for traditional measurement method, so can obtain reliably, measurement result accurately.
Utility model content
The utility model, for the problems referred to above, proposes a kind of measurement measuring system of loudspeaker assembly resonance frequency.
The measuring system of a kind of loudspeaker assembly resonance frequency that the utility model proposes can measure the resonance frequency of diffuser (vibrating diaphragm) and centring disk exactly.
The technical scheme that the utility model technical solution problem adopts is:
The loudspeaker assembly resonance frequency measuring system that the utility model provides, comprise loudspeaker assembly resonance frequency measuring system, it is characterized in that this system comprises data collection and analysis processor, power amplifier, excitation sound source, laser displacement sensor, microphone, excitation workbench, operative employee's station and assembled tool fixture; Operative employee's station table top is provided with at least a set of assembled tool fixture with embedded mode; 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 on excitation workbench faces the tested speaker parts be sandwiched in assembled tool fixture; Laser displacement sensor and microphone are fixed on the multifunctional measuring support of (Z-direction) movement up and down, multifunctional measuring support is fixed on twin shaft slide unit, twin shaft slide unit is located in operative employee's station overlying guide rail, and before and after twin shaft slide unit does in guide rail, (X-direction) and left and right (Y direction) optional position are moved;
Described data collection and analysis processor is connected to power amplifier, laser displacement sensor, microphone, and power amplifier is connected with excitation sound source, facing to tested speaker parts when laser displacement sensor and microphone are measured;
The function of described data collection and analysis processor is: be responsible for producing pumping signal, to measuring that the signal that obtains gathers, analyzing and processing, preservation and display;
The function of described power amplifier is: the pumping signal sent by data collection and analysis processor carries out amplifying rear promotion excitation loudspeaker vibration.
The function of described laser displacement sensor is: gather the displacement signal of unit under test and transfer to data collection and analysis processor.
The function of described microphone is: the acoustical signal that pickup is sent by excitation loud speaker when carrying out frequency response calibration also transfers to data collection and analysis processor.
Described tested speaker parts comprise diffuser or vibrating diaphragm and centring disk.
Excitation workbench is placed on below operative employee's station, two table surfaces are parallel to each other, and leave gap, the excitation sound source be located on lower excitation workbench faces the tested speaker parts be sandwiched in assembled tool fixture be located at above operative employee's station, certain gap is had between excitation sound source and tested speaker parts, air opens wide between the two, does not form cavity.
Excitation sound source is one or more dissimilar loud speakers; Described assembled tool fixture is made up of the annulus that a series of radius is different, and each annulus can combinationally use mutually; Many cover assembled tool fixtures are provided with at operative employee's station table top.
The utility model has the advantages that: can facilitate and measure the resonance frequency obtaining the loudspeaker assembly comprising cone (or vibrating diaphragm) and centring disk quickly, owing to have employed compensating for frequency response and the adjustment of pumping signal size, the measurement result obtained is more reliable, accurate.
Accompanying drawing explanation
Fig. 1 measuring system block diagram.
Fig. 2 measuring system frock cutaway view.
Fig. 3 measuring system frock two view.
Fig. 4 assembled tool fixture.
Fig. 5 test and excitation time domain plethysmographic signal figure.
Pumping signal time domain beamformer after Fig. 6 compensating for frequency response.
The frequency response of Fig. 7 compensating for frequency response fore-and-aft survey environment.
Fig. 8 measurement result figure.
Embodiment
Below in conjunction with drawings and the specific embodiments, the utility model is described further.
As shown in Figure 1, the utility model comprises: data collection and analysis processor (1), power amplifier (2), excitation sound source (loud speaker) (3), tested speaker parts (4), laser displacement sensor (5), microphone (6), operative employee's station (7) and excitation workbench (8).
Operative employee's station (7) table top is provided with measurement in a closed series fixture with embedded mode, and measurement in a closed series fixture can fix the tested speaker parts of different size; Excitation sound source (3) is arranged on excitation workbench (8) table top, excitation workbench (8) is placed on operative employee's station (7) below, and (two table surfaces are parallel to each other, except being positioned over same ground, without any Hard link), the excitation sound source (3) of below faces the tested speaker parts (4) of top; Laser displacement sensor (5) and microphone (6) are fixed on multifunctional measuring support, and multifunctional measuring support can (Z-direction) move up and down; Multifunctional measuring support is fixed on twin shaft slide unit, twin shaft slide unit, by being fixed on the guide rail of operative employee's station (7) top, can do front and back (X-direction) and left and right (Y direction) movement arbitrarily at operative employee's station (7) table top superjacent air space;
The course of work of this measuring system is: the pumping signal that data collection and analysis processor (1) produces gives excitation sound source (3) after power amplifier (2) amplifies, and excitation sound source sends out sound wave promotion tested speaker parts (4) the generation vibration that (3) go out; Laser displacement sensor (5) picks up the vibration displacement signal of tested speaker parts and sends data collection and analysis processor (1) back to.Data collection and analysis processor (1) processes upper displacement signal, and by result display and preservation.
In order to reduce the performance requirement to excitation sound source (loud speaker) (3), eliminate the harmful effect encouraging sound source (3) itself and measurement environment to produce tested speaker parts (4) vibration, the certainty of measurement of raising system, before native system is formally measured, system must first to comprising excitation sound source (3), tested speaker parts (4), operative employee's station (7) and the acoustic enviroment encouraging workbench (8) and ambient air thereof to form do compensating for frequency response, make under the excitation of excitation sound source, stressed substantially identical in the arbitrary frequency point of tested speaker parts in measurement frequency band.
The process of compensating for frequency response is as follows:
The pumping signal that data collection and analysis processor (1) produces gives excitation sound source (3) after power amplifier (2) amplifies, and excitation sound source sends out sound wave promotion tested speaker parts (4) the generation vibration that (3) go out; Meanwhile, microphone (6) is aimed at the center of unit under test (4), and calculated the frequency response now comprising excitation sound source (3), tested speaker parts (4), operative employee's station (7) and the acoustic enviroment that encourages workbench (8) and ambient air thereof to form by the acoustical signal that collects and pumping signal.
The formula of calculated frequency response is
Wherein
hp (f)be the frequency domain representation of frequency response, P (f) is the frequency domain representation of the acoustical signal that microphone pick arrives, and U (f) is the frequency domain representation of pumping signal.
After acquisition frequency response, pass through formula
calculate the pumping signal after compensating for frequency response, and the pumping signal using this signal as excitation sound source.Wherein,
u ' (t)for the pumping signal after compensating for frequency response,
u (t)for the pumping signal before compensating for frequency response, * represents convolution,
hp (f)to serve as reasons the frequency response that (1) calculate
, -1 ffor inversefouriertransform.
So far, frequency compensation link completes.
Fig. 6 is the pumping signal after compensating.Fig. 7 is the frequency response of acoustic measurement environment before and after compensating for frequency response.
After completing above-mentioned compensating for frequency response and before formal measurement, system also needs the adjustment carrying out pumping signal size.By laser displacement sensor (5) pick up collection displacement signal calculate current amplitude, then make comparisons with target amplitude and adjust the size of pumping signal.If current amplitude is greater than target amplitude, then reduce pumping signal size; Otherwise it is then contrary.The amplitude of tested speaker parts is finally made to reach desired value.
Pumping signal size adjustment process is as follows:
The pumping signal that data collection and analysis processor (1) produces gives excitation sound source (3) after power amplifier (2) amplifies, and excitation sound source sends out sound wave promotion tested speaker parts (4) the generation vibration that (3) go out; Meanwhile, when guaranteed output amplifier (2) gain is constant, laser displacement sensor (5) is aimed at the marginal position of unit under test (4), and adjusted by the size of displacement signal to pumping signal collected, that is: if the amplitude calculated by displacement signal has exceeded target amplitude, then reduce the size of pumping signal, on the contrary then contrary.
Be (Xmax-Xmin)/2 by the mode of displacement signal calculated amplitude, wherein Xmax is the maximum of displacement signal, and Xmin is the minimum value of displacement signal.
Owing to adopting the mode being calculated tested speaker parts amplitude by the maximum of displacement signal and minimum value, therefore, laser displacement sensor before each measurement need not school zero, only needs to ensure the maximum of displacement signal and minimum value in the range ability of laser displacement sensor just.
So far, amplitude adjustment link completes.
After completing above-mentioned compensating for frequency response and amplitude adjustment process, excitation sound source (3) is promoted by the pumping signal after adjustment, use laser displacement sensor (5) to pick up the vibration displacement signal of unit under test (4) simultaneously, by the relational expression of this signal and sine sweep signal, i.e. formula
, calculate the frequency response of displacement signal, find out its frequency corresponding to frequency response maximum, be the resonance frequency (as shown in Figure 8) of unit under test.In above-mentioned formula
hx (f)be the frequency domain representation of frequency response, X (f) is the frequency domain representation of the displacement signal that laser displacement sensor collects, and U (f) is the frequency domain representation of pumping signal.
Determine in pumping signal, under prerequisite that power amplifier gain is constant, the amplitude that different tested speaker parts produce is not quite similar.Therefore, native system also adds feedback modifiers function, that is: when by displacement signal, system detects that the amplitude of tested speaker parts does not reach appointment amplitude, automatically will start the resonance frequency that amplitude calibration function also measures tested speaker parts again.
Finally, should be noted that: above embodiment is only in order to illustrate the utility model and technical scheme described by unrestricted the utility model; Therefore, although this specification has done detailed description with reference to the above embodiments to the utility model, it will be understood by those of skill in the art that and still can modify to the utility model or equivalent replacement; And all do not depart from technical scheme and the improvement thereof of the spirit and scope of utility model, it all should be encompassed in the middle of right of the present utility model.
Claims (4)
1. a loudspeaker assembly resonance frequency measuring system, is characterized in that this system comprises data collection and analysis processor, power amplifier, excitation sound source, laser displacement sensor, microphone, excitation workbench, operative employee's station and assembled tool fixture; Operative employee's station table top is provided with at least a set of assembled tool fixture with embedded mode; 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 on excitation workbench faces the tested speaker parts be sandwiched in assembled tool fixture; Laser displacement sensor and microphone are fixed on the multifunctional measuring support that moves up and down, multifunctional measuring support is fixed on twin shaft slide unit, twin shaft slide unit is located in operative employee's station overlying guide rail, and before and after twin shaft slide unit does in guide rail and optional position, left and right is moved;
Described data collection and analysis processor is connected to power amplifier, laser displacement sensor, microphone, power amplifier and excitation
Sound source connects, facing to tested speaker parts when laser displacement sensor and microphone are measured;
The function of described data collection and analysis processor is: be responsible for producing pumping signal, to measuring that the signal that obtains gathers, analyzing and processing, preservation and display;
The function of described power amplifier is: the pumping signal sent by data collection and analysis processor carries out amplifying rear promotion excitation loudspeaker vibration;
The function of described laser displacement sensor is: gather the displacement signal of unit under test and transfer to data collection and analysis processor;
The function of described microphone is: the acoustical signal that pickup is sent by excitation loud speaker when carrying out frequency response calibration also transfers to data collection and analysis processor.
2. loudspeaker assembly resonance frequency measuring system according to claim 1, is characterized in that described tested speaker parts comprise diffuser or vibrating diaphragm and centring disk.
3. loudspeaker assembly resonance frequency measuring system according to claim 1, it is characterized in that excitation workbench is placed on below operative employee's station, two table surfaces are parallel to each other, and leave gap, the excitation sound source be located on lower excitation workbench faces the tested speaker parts be sandwiched in assembled tool fixture be located at above operative employee's station, have certain gap between excitation sound source and tested speaker parts, air opens wide between the two, does not form cavity.
4. loudspeaker assembly resonance frequency measuring system according to claim 1, is characterized in that excitation sound source is one or more dissimilar loud speakers; Described assembled tool fixture is made up of the annulus that a series of radius is different, and each annulus can combinationally use mutually; Many cover assembled tool fixtures are provided with at operative employee's station table top.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201520292814.7U CN204559886U (en) | 2015-05-08 | 2015-05-08 | Loudspeaker assembly resonance frequency measuring system |
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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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