Abstract
Under the prerequisite that the air flows, for obtaining a simplified sound absorbing structure which is absorbed much noise as possible, and develop a dedicated measurement apparatus for evaluating the transmission loss of the noise, and reports the examination results and the measurement results. While various soundproofing is carried out in order to prevent the noise and look at this time for them mute. Tone generator and for flowing exhaust gas and air different from the sound insulation and partitioning on the wall outside the factory and buildings release wind machines and outdoor unit, which silencer is mounted such as ventilators. By examining this characteristic because the mute amount of change coming by the structure and material to think that it might be of help to the noise troubleshooting. Than parallel-type structure, internal is observed complex maze type structure is high silencing performance, was able to confirm that there is a silencing effect against high frequency.
