To prevent a sound insulation property from deteriorating due to low frequency band resonant transmission and reduce noise in a medium/high frequency range by arranging sound absorbing material on one part in an air layer between a ceiling slab and a vent material hung from it downward.
From a ceiling slab 1 made of a concrete slab and the like, a vent material 3 is hung through anchor bolts 11, and the vent material 3 is used as an internally faced ceiling material. A sound absorbing material 4 is arranged on only one part of air layers 2, 2 in a space between the ceiling slab 1 and the vent material 3. As for the sound absorbing material 4, a material constituted of a fiber aggregate having a fixed gas permeability and a ventilation resistance is used. Then, the sound insulation property against heavy weight source floor impact sound by low frequency band resonant transmission can be preventing from deteriorating, and simultaneously light weigh source floor impact noise in the medium/high frequency range can be reduced.
TSUKADA SUSUMU
INABA KENJI
TAKESHITA MICHITAKA
