PENGUKURAN TINGKAT PENYERAPAN BUNYI KEPINGAN BATANG KELAPA SAWIT DENGAN MENGGUNAKAN TABUNG IMPEDANSI

Abstract

Research on measuring of levels of sound absorption by a piece of palm trunk was done. Sample of palm trunk used in this study was 22 years old and made into rectangular pieces with a size of 23 x 23 cm. The thickness of the samples was varied, namely 6mm, 9mm, 15mm. The source of sound used was generated from sweep function generator. The sound intensity inside the impedance tube before and after penetrating the sample was recorded using sound level meter. The sound frequency range used in this research was 100 Hz - 1000 Hz. The results indicated that in general, the sound intensity increases with the increase of sound frequency. However, the intensity of the sound was reduced very significantly after penetrating the sample inside the tube. For high frequency, namely 1000 Hz then the percentage of sound absorbtion by a piece of trunk palm with the thickness of 6 mm, 9 mm and 15 mm was 3.4 %, 5.7 % and 14 % respectively, while, for low frequency, namely 100 Hz, then the percentage of sound absorbtion by the material with the thickness of 6 mm, 9 mm and 15 mm was 5.6 %, 8.3 % and 12 % respectively