Abstract
An acoustic transparent wall was developed and applied to a ceiling mounted ventilation fan to reduce its noise radiation. The acoustic transparent wall is a plate through which sound can pass easily but flow cannot pass. If the casing of a ventilating fan is constructed by an acoustic transparent wall, the noise generated by the fan is expected to be radiated into the ceiling and hardly into the room. It is composed of a thin film, clothes and wire nets. In this paper, their appropriate combinations were studied and its noise reducing effect was proved. A trial application of this technique to a real machine obtained 3〜4 dB noise reduction.
