Sound Quality Control by Microperforated Panel Housing Device

The passive noise control system in duct is conventionally to improve the transmission loss or insertion loss. However, the sound quality enhancement to meet the human perception is rarely explored. This study presents an investigation and optimization for sound quality of the ducted-fan noise by micro-perforation panel (MPP) housing device. Through the vibro-acoustic coupling as well as the sound absorption by the micro-perforations, the noise suppression can be achieved. Since loudness is the most relevant sound quality metric, it is served as the objective function in the optimization analysis. A two-dimensional theoretical model, capable of dealing with strong coupling among the vibrating micro-perforated panel, sound radiation from the rotating fan with a dipole nature, and sound fields inside the cavity and the duct is developed. The theoretical results are validated by the numerical simulation based on the finite element analysis and the experimental measurement in the anechoic chamber. The assessment by using Zwicker's loudness model shows that the proposed housing device is able to accomplish sound quality improvements of the ducted-fan system.