Active Noise Controller Overview
Active noise control systems provide sound attenuation by introducing a second, electronically generated, sound field into the acoustic environment. If the amplitude of the second sound field is the same as the first, but the phase inverted, then the two will cancel. The end result is quiet. As we have discussed in the preceding chapters, the potential for active control to provide a satisfactory result is largely a function of the physical acoustics of the problem: the characteristics of the unwanted sound field, the response of the acoustic system, the location of the loudspeakers, etc. We can conclude that if the physical acoustics “aren’t right,” then even the biggest, best, and most expensive active noise control system will not be able to provide the desired levels of sound attenuation. Active noise control is not a universal panacea; the problem must be amenable to the recommended solution.
KeywordsPhysical Acoustics Digital Filter Digital System Sound Field Finite Impulse Response Filter
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