Effect of resonator arrangement on sound transmission loss through duct with several resonators

Installing a resonator increases sound transmission loss through a duct at its resonant frequency. When several resonators with different resonant frequencies are installed, the sound transmission loss can be expected to increase over a wide frequency range. In such cases, the arrangement of the resonators may affect the sound transmission loss. This study aims to quantitatively investigate the effect of resonator arrangement on sound transmission loss for a cylindrical duct containing a series of disk-shaped resonators. Based on analytical calculations, sound transmission loss was found to vary depending on the resonator arrangement. A negative correlation was observed between the indices evaluating the arrangement and the sound transmission loss. For fewer than five resonators, it was confirmed that the sound transmission loss when the resonator with the largest diameter was placed at the edge was higher than that when it was placed at the center. This effect tended to weaken as the number of resonators increased.