CN102075846B - Acoustic filter device for high-directivity audio loudspeaker measuring system - Google Patents
Acoustic filter device for high-directivity audio loudspeaker measuring system Download PDFInfo
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- CN102075846B CN102075846B CN 201010617076 CN201010617076A CN102075846B CN 102075846 B CN102075846 B CN 102075846B CN 201010617076 CN201010617076 CN 201010617076 CN 201010617076 A CN201010617076 A CN 201010617076A CN 102075846 B CN102075846 B CN 102075846B
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Abstract
The invention relates to an acoustic filter device for a high-directivity audio loudspeaker measuring system, which is characterized in that the acoustic filter device comprises a base (1), a microphone (2), a support (3) and a front panel (4); a through hole is arranged in the center of the base (1) and is used for arranging the microphone (2) in a penetrating way; the front panel (4) is fixed right ahead the microphone (2) through the support (3); and the front panel (4) is made of a metal material with Brinell hardness number being more than 100HB. The acoustic filter device provided by the invention has a low-pass characteristic, can greatly attenuate ultrasound and has a small impact on audio sounds. Thereby, measurement pseudo noises caused by the microphone can be effectively reduced.
Description
Technical field
The present invention relates to the acoustic measurement technical field, particularly a kind of sound filter for high directivity audio speaker measuring system.
Background technology
High directivity audio speaker system is a kind of New-type loudspeaker system from the directive property audible sound to specific direction that can launch, it is based on parametric array principle, sound signal is modulated on the ultrasonic carrier, after the ultrasound transducer array emission, because airborne nonlinear interaction produces the audible sound with high directivity.The high directivity audio speaker can be widely used in fields such as sound wave directional transmissions, secure communication.
When two row frequencies are respectively f
1And f
2Ultrasonic wave p
1And p
2After the ultrasonic transducer emission, because airborne nonlinear interaction can produce a plurality of sound waves of different frequencies, i.e. poor (the f of two frequencies
1-f
2) and two frequency sum (f
1+ f
2), and high-order harmonic wave.Because square being directly proportional of SATT coefficient and frequency makes radio-frequency component decay in communication process comparatively fast, so through only having the difference frequency sound wave after the propagation of a segment distance, the formation audible sound.But, have ultrasonic wave p simultaneously at near-field region
1And p
2With audible sound p
d, and because ultrasonic wave p
1And p
2Sound pressure level higher, especially when the near field generally more than 120dB, so can produce pseudo noise when directly measuring with microphone in this zone.Pseudo noise derives from two aspects, and the one, because the nonlinear interaction of the pre-amplifying circuit of microphone, the 2nd, because the sound radiation pressure of microphone face.The frequency of the pseudo noise of the two formation is two ultrasonic wave p
1And p
2Poor (the f of frequency
1-f
2), amplitude and ultrasonic wave p
1And p
2The product of amplitude is directly proportional, i.e. p
n∝ p
1p
2This shows that the pseudo noise that is caused by measuring system is identical with listened to the difference frequency acoustic frequency that the high directivity audio speaker produces, but amplitude and difference frequency wave frequency are irrelevant, and listened to the difference frequency acoustic amplitude that the high directivity loud speaker produces and the pass of difference frequency ripple frequency are
1≤n≤2 wherein.N determines by the Rayleigh distance ratio with absorption distance, when Rayleigh distance during greater than absorption distance, and n=2; When absorption distance much larger than Rayleigh apart from the time, n=1.Therefore, can judge whether filtering of pseudo noise according to the relation of the difference frequency magnitudes of acoustic waves that records and frequency.
The measurement of actual audible sound has seriously been disturbed in the existence of pseudo noise, especially when the near field, pseudo noise is more much bigger than the audible sound of the actual generation of high directivity audio speaker, therefore is necessary to design a kind of filter with the filtering ultrasonic wave, thereby the removal pseudo noise obtains real audible sound.
Summary of the invention
The objective of the invention is to, provide a kind of sound filter for high directivity audio speaker measuring system to keep audible sound with the filtering pseudo noise.
For achieving the above object, a kind of sound filter for high directivity audio speaker measuring system is characterized in that this filter comprises: base 1, microphone 2, support 3 and front panel 4;
The center of described base 1 is provided with a through hole, is used for wearing microphone 2; Described front panel 4 is fixed in the dead ahead of microphone 2 by support 3;
Described front panel 4 adopts ball hardness number to make greater than the metal material of 100HB.
Described support 3 length are 3cm～5cm.
Described support 3 is respectively perpendicular to described base 1 and described front panel 4.
Described support 3 adopts at least 2 pillars or annular guard.
Described front panel 4 is circular, hemisphere or spherical.
Described front panel 4 adopts iron material or aluminum.
Described front panel 4 disc diameters are 12mm～20mm.
This filter also comprises pipe; Described pipe is used for fixing described microphone 2.
The invention has the advantages that sound filter provided by the invention has low-pass characteristic, has than high attenuation ultrasonic, and rings less to the audio frequency sound shadow.Therefore, can effectively reduce the measurement pseudo noise that causes because of microphone.
Description of drawings
Fig. 1 is one of execution mode of high directivity audio speaker measuring system sound filter of the present invention;
Fig. 2 is to hyperacoustic oise insulation factor measurement result figure when adopting one of execution mode;
Fig. 3 is to the oise insulation factor measurement result figure of audible sound when adopting one of execution mode;
Fig. 4 is to the actual measured results figure of high directivity audio speaker when not adopting filter;
Fig. 5 is to the actual measured results figure of high directivity audio speaker when adopting one of execution mode;
Fig. 6 be high directivity audio speaker measuring system sound filter of the present invention execution mode two;
Fig. 7 be high directivity audio speaker measuring system sound filter of the present invention execution mode three;
Fig. 8 be high directivity audio speaker measuring system sound filter of the present invention execution mode four.
Accompanying drawing indicates:
1, base 2, microphone 3, support 4, front panel
Embodiment
Below in conjunction with drawings and Examples the present invention is further specified.
For a better understanding of the present invention, below in conjunction with the drawings and specific embodiments the present invention is described in further detail:
The invention reside in provides a kind of sound filter with low-pass characteristic, the ultrasonic composition of filtering, and keep audible sound.Technical scheme is:
The sound filter of high directivity audio speaker measuring system comprises: front panel, support and base.
Above-described sound filter is characterized in that microphone makes front panel be installed in the front end of microphone by support by the through hole at base center.
Described front panel is characterized in that, diameter is greater than 12mm, with the resonance of avoiding ultrasonic plate in front surface to cause.
Described front panel can be that ball hardness numbers such as aluminium, iron are greater than the metal material of 100HB.Because ultrasonic wave has highly directive, and front panel has certain degree of hardness, therefore, the front panel that is installed in the microphone front end can effectively be decayed ultrasonic, and for audio frequency sound, because its wavelength is bigger, can diffraction to microphone, so front panel is almost very little to the decay of audio frequency sound.
Described front panel, shape can be circular, hemisphere or spherical.
Described support can be 2 or a plurality of pillar or guard.
Sound filter provided by the invention has low-pass characteristic, has than high attenuation ultrasonic, and rings less to the audio frequency sound shadow.Therefore, can effectively reduce the measurement pseudo noise that causes because of microphone.
As shown in Figure 1, one of execution mode of a kind of sound filter of high directivity audio speaker measuring system, its front panel 4 is circular, support 3 is 2 pillars.
Above-described embodiment to the oise insulation factor measurement result of ultrasonic and audio frequency sound as shown in Figures 2 and 3.More than 15dB, in 0kHz-10kHz audio frequency sound wave frequency range increase is arranged slightly at the supersonic band mean transmission loss of the 30kHz-50kHz of directional loudspeaker, but on average in 5dB.As seen this embodiment ultrasonic wave of can effectively decaying, but ring very little to the audio frequency sound shadow.
In order to verify the validity of above-described embodiment, at anechoic chamber the high directivity audio speaker has been carried out actual measurement.The high directivity audio speaker is made up of the ultrasonic transducer unit of 91 diameter 16mm, and carrier wave is 40kHz, adopts the double-sideband modulation technology.Microphone adopts 1/4 inch of G.R.A.S company, the microphone of model: 46BE, places the high directivity speaker axis to 3 meters, and the frequency response of high directivity loud speaker is measured.Fig. 4 is the measurement result that does not add filter, because the audible sound that pseudo noise produces much larger than directional loudspeaker, and the amplitude of pseudo noise is directly proportional with the product of ultrasonic former ripple, thus the frequency response that records at this moment almost with frequency-independent.Fig. 5 is the measurement result behind adding above-described embodiment, and the frequency response curve of directional loudspeaker is consistent with 1.5 power trend of difference frequency ripple frequency, proves that pseudo noise is by filtering at this moment.
As shown in Figure 6, two of a kind of execution mode of sound filter of high directivity audio speaker measuring system, its front panel 4 is hemispheres, support 3 is 2 pillars.
As shown in Figure 7, three of a kind of execution mode of sound filter of high directivity audio speaker measuring system, its front panel 4 is circular, support 3 is annular guards.
As shown in Figure 8, four of a kind of execution mode of sound filter of high directivity audio speaker measuring system, its front panel 4 is hemispheres, support 3 is annular guards.
It should be noted last that above embodiment is only unrestricted in order to technical scheme of the present invention to be described.Although the present invention has been described in detail with reference to embodiment, those of ordinary skill in the art is to be understood that, technical scheme of the present invention is made amendment or is equal to replacement, do not break away from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.
Claims (7)
1. a sound filter that is used for high directivity audio speaker measuring system is characterized in that this filter comprises: base (1), microphone (2), support (3) and front panel (4);
The center of described base (1) is provided with a through hole, is used for wearing microphone (2); Described front panel (4) is fixed in the dead ahead of microphone (2) by support (3);
Described sound filter also comprises pipe, and this pipe is used for fixing described microphone (2);
Described front panel (4) adopts ball hardness number to make greater than the metal material of 100HB.
2. the sound filter for high directivity audio speaker measuring system according to claim 1 is characterized in that described support (3) length is 3cm～5cm.
3. the sound filter for high directivity audio speaker measuring system according to claim 1 and 2 is characterized in that described support (3) is respectively perpendicular to described base (1) and described front panel (4).
4. the sound filter for high directivity audio speaker measuring system according to claim 3 is characterized in that described support (3) adopts at least 2 pillars or annular guard.
5. the sound filter for high directivity audio speaker measuring system according to claim 1 is characterized in that described front panel (4) is circular, hemisphere or spherical.
6. the sound filter for high directivity audio speaker measuring system according to claim 1 is characterized in that described front panel (4) adopts iron material or aluminum.
7. the sound filter for high directivity audio speaker measuring system according to claim 1 is characterized in that described front panel (4) disc diameter is 12mm～20mm.
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| CN 201010617076 CN102075846B (en) | 2010-12-22 | 2010-12-22 | Acoustic filter device for high-directivity audio loudspeaker measuring system |
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|---|---|---|---|
| CN 201010617076 CN102075846B (en) | 2010-12-22 | 2010-12-22 | Acoustic filter device for high-directivity audio loudspeaker measuring system |
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| CN102075846A CN102075846A (en) | 2011-05-25 |
| CN102075846B true CN102075846B (en) | 2013-09-11 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104683906B (en) * | 2013-11-28 | 2018-06-05 | 中国科学院声学研究所 | For the phonon crystal filter of high directivity audio speaker measuring system |
| CN113615212B (en) * | 2019-07-15 | 2024-04-12 | 中科新悦（苏州）科技有限公司 | High-sound-pressure microphone calibration device, system and method |
| CN110346829A (en) * | 2019-07-31 | 2019-10-18 | 中国科学院声学研究所 | A kind of buried non-metallic object detection system of shallow-layer |
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| CN101203062A (en) * | 2007-07-20 | 2008-06-18 | 徐利梅 | Method for numeral sound signal processing and digital type sound frequency directional loudspeaker |
| CN101790118A (en) * | 2009-12-31 | 2010-07-28 | 瑞声声学科技(深圳)有限公司 | Audio-frequency directional loudspeaker system and signal processing method thereof |
| CN101820564A (en) * | 2010-03-16 | 2010-09-01 | 电子科技大学 | Minitype multichannel audio frequency directional loudspeaker |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007251901A (en) * | 2006-03-20 | 2007-09-27 | Seiko Epson Corp | Directional loudspeaker |
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| CN101203062A (en) * | 2007-07-20 | 2008-06-18 | 徐利梅 | Method for numeral sound signal processing and digital type sound frequency directional loudspeaker |
| CN101790118A (en) * | 2009-12-31 | 2010-07-28 | 瑞声声学科技(深圳)有限公司 | Audio-frequency directional loudspeaker system and signal processing method thereof |
| CN101820564A (en) * | 2010-03-16 | 2010-09-01 | 电子科技大学 | Minitype multichannel audio frequency directional loudspeaker |
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| DEVELOPMENT OF A DIRECTIONAL LOUDSPEAKER SYSTEM FOR SOUND REPRODUCTION;Peifeng Ji, Chao Ye, Jing Tian;《IEEE》;20071231;1-8 * |
| JP特开2007-251901A 2007.09.27 |
| Peifeng Ji, Chao Ye, Jing Tian.DEVELOPMENT OF A DIRECTIONAL LOUDSPEAKER SYSTEM FOR SOUND REPRODUCTION.《IEEE》.2007,1-8. |
| 吴鸣,曹洁,匡正,王华朋,杨军.特定频带 扬声器频响补偿技术.《声学学报》.2010,第35卷(第2期),全文. |
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