Abstract
This report is tried to clarify the sound absorption character of porous sintered aluminum base sheets by vertical sound absorption method with the following samples; (1) a perforated aluminum metal sheets, (2) the perforated aluminum metal sheet having porous sintered aluminum or glasswool, (3) the porous sintered aluminum base sheets, and (4) a pore-simplified sintered aluminum base sheet prepared by paraffine treatment.
From the above experiments, it can be said that the porous sintered aluminum base material has a three-dimentional structure, therefore the sound absorption curve is similar to of the perforated metal, but the former has smoother and wider sound absorption curves against the frequency than the latter.
An effect of the air gap behind the porous sintered aluminum base sheet on the sound absorption was also examined. It was found that, in order to get a more good sound absorption curve in wider frequencies, it is important to set the sheet in the apparatus with some inclined air gaps against the sound waves.
