Glass tube Gamelan Design for Preparation on Installation Art Applications

Scale plays important role in musical instrument design. Harmonic instruments adopt 12-tet (12 tone equal temperaments) scale, and non-harmonic instruments use scales typically from 5 to 7 notes to the octave with uneven intervals in general such as gamelan [1]. In this paper, we were dealing with a particular nonharmonic instrument design where a set of equal size glass tubes filled with water of different levels to create scale for installation art application. The level is properly adjusted based on a calculated dissonance measure. We will first review the work by Promp and Levelt’s [2] mathematical model that utilizes dissonance curve of sound to find the proper music scale for non-harmonic sounding material. The model is adjusted to fine tune the measure and is tested by verifying a real xylophone bought from Java islands. We then use this model to do a preliminary design of our water filled glass tube instrument. It has shown the glass tube instruments have 7-note scales that resemble a Pelog gamelan but with uneven intervals. And quite opposite to people’s view that the higher the water level the lower the pitch. It is because higher water level tends to smooth the vibration cycle of the glass. The design procedure can be served as a reference for building much larger tube (glass or PVC) placed in park or recreation ground for intelligent living application. 1