Design of Active Noise Reduction Equipment Using Multipole Secondary Source

The development of the active noise reduction method is quite interesting because it is more economical and effective in reducing noise than passive noise reduction. However, active noise reduction using a conventional secondary source can become complicated if required significant noise reduction. It will need a large number of secondary sources. The active noise reduction is also ineffective to reduce high-frequency noise. Multipole secondary source is developed to solve those problems. Multipole secondary source is a combination of monopoles, dipoles, and quadrupoles secondary sources which are arranged in a certain way. The dodecahedron speaker model is chosen to be able to produce a multipole secondary source. The optimal secondary source strength can be obtained through the direct approach and the optimization approach. The optimization approach method is chosen because it depends on the frequency variable for determining the strength of multipole secondary sources. The design of active noise reduction equipment can be applied to reduce noise from industrial machinery.