Abstract
A side branch silencer which is one of the reactive-type silencers is effective for the reduction of periodical sound. It is often used to reduce noise such as those due to pulsation pressure. This is especially effective for noise generating a single frequency. However, an effective frequency range is comparatively narrow obliging the silencer to be enlarged as a countermeasure of low frequency sound. This may cause problems concerning installation space. In order to develop a side branch silencer which is effective at low frequency ranges, a side branch with the finite impedance at the end was made and examined. As a result, it was clarified that this side branch was useful for low frequency noise.
