Vibration and Acoustics Characteristic of Gong

Low, Suk Yin (2024) Vibration and Acoustics Characteristic of Gong. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

For this research, a gong singing bowl will be used as the test specimen. Each singing bowl has a unique feature, this research aims to investigate the characteristics of the gong singing bowl. Specifically, the study will identify the natural frequency and mode shape of the bowl using FEA and EMA methods. The results obtained from both methods will be compared. Moreover, it’s important to note that as the mode shape increases, the natural frequency also increases. Furthermore, while the mode shapes of four of these modes appear almost identical. In EMA, the Modal Assurance Criterion (MAC) was utilized to ensure the selection of dissimilar mode shapes. The lowest result obtained was 0.128%, representing the comparison between mode 1 and mode 4. In the context of acoustics, tests were conducted at four distinct striking locations to assess time duration, fundamental frequency, and sound intensity. Location 1 is at the center, while Location 4 is on the outer edge of the gong singing bowl. Location 2 on the gong singing bowl has been observed to produce a sustained sound for a longer duration compared to other striking locations. The sound generated at this location can persist for as long as 43 seconds before gradually diminishing and coming to a complete stop. Across all four locations, the fundamental frequency consistently ranged between 92Hz and 94Hz. Consequently, the gong singing bowl appears to be calibrated to produce the musical note F#2. The F# musical note is also known as the F musical note, which is associated with the heart chakra.