Insertion loss studies of a baffle‐simple expansion chamber system

Abstract

Insertion loss (IL) is the difference of sound pressure levels measured at a reference point without and with a muffler in a duct system. Thus, IL describes the acoustical performance of the whole system which includes source, muffler, and tail pipe. IL studies of a simple expansion chamber has been reported in the literature. However, there are not many IL studies of complicated geometries in a muffler from a system design point of view. This study reports both experimental and analytical work on the influence of a baffle on IL of a simple expansion chamber. The hole diameter and location of the baffler are the parameters of this study. An Altec electroacoustic driver is used as a source for experimental work conducted in an anechoic chamber. The analytical work is carried out using the boundary element method. The results indicate a significant influence (due to the interaction of source and load) on the insertion loss.