Abstract
Measurements were made of the frequencies and modes of resonant vibrations of fibrous acoustic tiles which were set up into a scale model so named by the Japan Broadcasting Corporation the "B-type standard studio wall structure". Each piece of the tilework of the model showed a different resonant characteristic due to the non-uniformity of the texture of the tile piece and to slight differences originating from accidental constructional irregularities. The frequency of occurrence of resonance was therefore measured for band-widths of 25 c/s below 300 c/s, and for band-widths of 50 c/s above 300 c/s on a large number of pieces of tile in the model. As a result of these measurements, the occurring frequency of resonance was found to be dominant around and below 200 c/s. The frequency characteristics of the reverberant sound absorption coefficient of this type of wall structure were also measured. From these results, it can be qualitatively interpreted that the increase of sound absorption below about 200c/s generally found in such types of wall structure is due to the most dominant occurrence in this frequency band of the resonant panel vibrations of the component pieces of tiling.
