Abstract:

The transfer matrix method has been extensively explored by many researchers for analysing acoustic duct systems. However, there does not exist a comprehensive source that elaborates the use of transfer matrix method for evaluating the performance of acoustic filters. The current approach describes a detailed step-by-step method for evaluating in-duct net acoustic power transmission for a harmonic plane wave travelling in a circular duct with an attached cylindrical Helmholtz resonator using the transfer matrix method. The net acoustic power transmission is evaluated using two different methods: (1) the product of acoustic pressure and acoustic volume velocity at the duct exit, and (2) estimates of the in-duct sound field using the two-microphone technique.