Enhancing ventilation holes acoustic performance through perforated absorption plate

A vent hole unit, referred to as the soundproofing ventilation hole unit (SVHU), was introduced in a prior study. This unit integrates soundproofing and ventilation functions and consists of a rectangular cavity with an inlet and an outlet, designed for installation within residential walls. The sound waves propagating through the cavity include both plane wave components and higher-order wave components. The higher-order waves consist of multiple sound pressure components, and their interactions increase the overall sound pressure level. Therefore, without implementing countermeasures for higher-order waves, the noise reduction effect of the SVHU cannot be expected. To address this issue, a cavity featuring a perforated sound-absorbing plate (PSAP) was proposed, and both theoretical analysis and experimental validation were conducted. The results confirmed that the use of the perforated sound-absorbing plate significantly reduced the higher-order sound pressure components. It was confirmed through experimentation that Insertion Loss in the frequency range between 2kHz and 16kHz after insertion of PSAP is increased by 12dB.