Combined secondary sound source design method applied to active noise control

Abstract

The invention relates to a combined secondary sound source design method applied to active noise control, which comprises measuring central frequency f0 in energy centralized frequency band of the primary noise field, and space distribution characteristic of the primary sound field; setting number of combined secondary sound source between 4 and 8; setting distance between the secondary sound source to the center of the primary noise center as not exceeding 0.5 times of wavelength corresponding to sound source central frequency; forming the secondary sound source by two loudspeaker units closely abutting against each other, having a secondary channel shared thereby; computing source strength ratio an, 12, (n=1, 2, ..., N) of the loudspeaker close to the primary source and the loudspeaker remote to the primary source respectively according to distribution characteristic of the primary noise field and space position of the secondary sound source; and selecting two loudspeaker units having frequency response close to each other as unit 1 and unit 2 in the combined secondary sound source to form the combined secondary sound source according to source strength amplitude ratio of the secondary sound source. The method evidently enhances noise reducing performance, and the combined source is simple in construction, suitable for multiple kinds of sound field environment.

Description

1. Technical field [0001] The invention relates to a combined secondary sound source for use in an active noise control system. 2. Background technology [0002] In active noise control, a loudspeaker system is generally used as the secondary control sound source. This kind of monopole secondary source has a simple structure, and the source intensity of the secondary source is easy to adjust, but each monopole secondary source must correspond to a secondary channel, resulting in a large number of secondary channels required by the control system. Mangiante designed a self-pointing tripole source based on JMC theory and applied it to the noise control of one-dimensional pipelines (G. Mangiante et al., Proceedings of ACTVIE 99, 1999, pp.493-502), and Beauvilain designed four The combined sound source of poles and octopoles is used in the noise control of three-dimensional space free field (T.A.Beauvilain et al., J.Acoust.Soc.Am., Vol.107, No.3, pp.1189-1202, 2000 ), but the ...

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Problems solved by technology

This kind of monopole secondary source has a simple structure, and the source intensity of the secondary source can be easily adjusted, but each monopole secondary source must correspond to a secondary channel, resulting in a large number of secondary channels required by the control system

Mangiante designed a self-pointing tripole source based on JMC theory and applied it to the noise control of one-dimensional pipelines (G. Mangiante et al., Proceedings of ACTVIE 99, 1999, pp.493-502), and Beauvilain designed four The combined sound source of poles and octopoles is used in the noise control of three-dimensional space free field (T.A.Beauvilain et al., J.Acoust.Soc.Am., Vol.107, No.3, pp.1189-1202, 2000 ), but the number of speaker units in these multi-pole sound sources has reached 3 or even 4, and the peripheral signal processing circuit is complex, which is not convenient for engineering realization

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