| Keywords |
Mulberry paper(Hanji) ; Absorber ; Porous material ; Sound absorption coefficient ; Noise reduction coefficient |
| Abstract |
The aim of this study is to examine the absorption coefficient of absorber with mulberry paper (Hanji) which has been used as a material of traditional window or door in Korea. The specimens were prepared in a total of 24 cases and measurements were carried out in acoustic chamber according to KS F 2805. And as a case study for practical application, measurements for reverberation time (RT), definition (D50) and rapid speech transmission index (RASTI) were carried out in a real room by installing the absorbers with mulberry paper. The measurement results in acoustic chamber showed that the absorption coefficient of only mulberry paper was very low and Noise Reduction Coefficient (NRC) was 0.01. But the absorption coefficients of specimens consist of mulberry paper with air cavity and porous material were remarkably changed in mid-frequencies. In general, NRC of these absorbers were counted up to 0.21~0.65 and the resonance frequencies were shifted to lower frequency range by increasing the thickness of air cavity and porous material. And the test results in a real room showed that the absorbers with mulberry paper were useful for controlling the acoustic performance to that extent by only porous absorber which is broadly used. |