Active Control of Exhaust Noise from a Muffler in Consideratin of the Location of Secondary Source

Abstract

The purpose of the present investigation is to design an adaptive noise control muffler which has the most suitable location of secondary source. In the experiment, the distribution of sound pressure level in the muffler model has been measured by a sound visualization technique in order to obtain the maximum sound reduction by the minimum secondary sound under active control. The experimental results show that the target frequency could well be attenuated when the distance between the primary source and the secondary source is equal to the length eguivalent to one-half of the wave length of a target sound or its integral multiples.