FEASIBILITY STUDY ON THE USE OF SILICON-BRONZE ALLOY AS AN ALTERNATIVE MATERIAL FOR BALINESE MUSICAL INSTRUMENTS

摘要

This research was carried out to investigate the acoustics feasibility of using silicon-bronze (Cu-5%Si) alloy to replace tin-bronze (Cu-20%Sn) alloy for Balinese traditional musical instruments. This research is the next step of the previous research that has sucessfully showed better mechanical properties of Cu-Si alloy compared to Cu-Sn alloy. The acoustical properties of interest in this study are: speed of sound (c), sound radiation coefficient (R) and frequency resistance (i.e. frequency's shift). The casted alloys were cut and machined for the test specimens. The acoustical properties of both alloys were measured and compared. The investigations were carried out according to ASTM Standard E 1876-01. For frequency shift investigation, the original fundamental frequency of each alloy is measured and then each alloy is subjected to impact load by hitting them as they are played in daily use. The total number of cycles (hits) experienced by each alloy is 72,000. Finally the resulting fundamental frequency is measured and compared to the previous (before hitting) conditions. The frequencies were measured after a certain interval numbers of hit until total of 72,000 hits. The results showed that Cu-Si alloy has speed of sound (c) and sound radiation coefficient (R) that are almost the same as those of Cu-Sn alloy. For frequency's shift, both alloy showed that they do not experience any frequency change after 72,000 hits. This is a good sign showing the potential of silicon-bronze alloy as an alternative material for Balinese musical instruments replacing tin-bronze alloy currently used.