Bamboo: unveiling its potential as a sustainable multi-frequency sound absorption solution for walls

This research presents a unique perspective on noise reduction in buildings, focusing on the use of bamboo, a rapidly renewable building resource, for sound absorption. The study investigates the acoustic properties of bamboo with saw-cutting holes, aiming to explore their potential as resonating multi-frequency sound absorbers in a low-frequency range. Bamboo inherently features hollow spaces between nodes, with consistent distances between them, although this gap may vary depending on the bamboo type and its dimensions, including length and width. The study examined saw-cut holes of varying sizes (3 mm, 5 mm, and 6 mm) for their sound absorption coefficients using two microphone impedance tube methods. Surprisingly, samples with different hole sizes exhibited nearly identical sound absorption coefficients (α = 0.90), but their maximum absorption frequencies shifted based on the hole size. Statistical t-test results also revealed significant differences in sound absorption performance across low-frequency bands. Additionally, numerical analysis of resonance frequency aligns with the estimated resonance frequency of samples. These findings could inform on the design of green walls for multi-frequency sound absorption in houses.