Electronic Theses and Dissertation

Penelitian ini dilakukan untuk mengetahui nilai koefisien absorpsi suara dari perpaduan serat kelapa dan serat abaka serta pengaruh ketebalan spesimen uji terhadap nilai koefisien absorpsi suara. Dalam penelitian ini spesimen uji dibuat menjadi 3 jenis dengan ketebalan yang berbeda dimana tiap spesimen terdiri dari serat dengan masing-masing berat 25 gr dan diameter 110 mm, dan memiliki variasi ketebalan 10 mm, 20 mm, dan 30 mm, spesimen uji disusun secara ber- lapis berbentuk seperti sandwich dengan pembagian serat kelapa berada diatas dan dibawah dengan masing-masing berat 12,5 gr dan serat abaka berada di antara kedua lapisan dengan berat 25 gr. Pengujian ini dilakukan dengan menggunakan metode tabung impedansi metode transfer fungsi (ISO 10534-2:1998) pada frekuensi 1/3 oktaf (100, 125, 160, 200, 250,
315, 400, 500, 630, 800, 1000, 1250, 1600, 2000, 2500, 3150, 4000, 5000, 6300, 8000, 10000) Hz. Hasil pengujian
menunjukkan bahwa nilai absorpsi pada ketiga spesimen berbeda. Nilai koefisien absorpsi suara maksimum didapatkan pada frekuensi 125 Hz dengan ketebalan 30 mm, sedangkan Nilai koefisien absorpsi suara minimum didapatkan pada frekuensi 125 Hz dengan ketebalan 10 mm. kesimpulan yang didapatkan dari pengujian diatas bahwa ketebalan perpaduan serat pada setiap spesimen dapat mempengaruhi nilai koefisien absorpsi.

This study was conducted to determine the value of the sound absorption coefficient of the combination of coco fiber and abaca fiber and the effect of the thickness of the test specimen on the value of the sound absorption coefficient. In this study, the test specimens were made into 3 types with different thicknesses where each specimen consisted of fiber with a weight of 25 g each and a diameter of 110 mm, and has a thickness variation of 10 mm, 20 mm, and 30 mm, the test specimens were arranged in layers in the form of a sandwich with coconut fiber division above and below with a weight of 12.5 grams each and abaca fiber between the two layers weighing 25 grams. This test was carried out using the im- pedance tube method of the transfer function method (ISO 10534-2:1998) at a frequency of 1/1 octave (100, 125, 160, 200, 250, 315, 400, 500, 630, 800, 1000, 1250, 1600, 2000, 2500, 3150, 4000, 5000, 6300, 8000, 10000) Hz. The test results showed that the absorption values in the three specimens were different. The maximum sound absorption coeffi- cient value is obtained at a frequency of 125 Hz with a thickness of 30 mm, while the minimum sound absorption coeffi- cient value is obtained at a frequency of 125 Hz with a thickness of 10 mm. The conclusion obtained from the above test is that the thickness of the fiber blend in each specimen can affect the value of the absorption coefficient.