Investigation of Sound Absorption Ability of Hinoki Cypress (Chamaecyparis obtusa) Cubes

Abstract

Today, commercialized Hinoki cypress cubes are used for fragrance, humidification, and pillows in Korea. In this study, the sound absorption ability of Hinoki cypress (Chamaecyparis obtusa) cubes was examined. The three groups of Hinoki cypress cubes were prepared depending on their dimension (L: 9 × 9 × 9, M: 7 × 7 × 7, S: 4 × 4 × 4 mm). Their sound absorption coefficient was examined after filling 6, 8, 10, and 12 cm height in impedance tubes, respectively. Overall, the sound absorption ability depending on dimension was superior in the M group compared to the L and S groups. Also, as the filling height increased, the sound absorption capacity increased. In sum, noise reduction coefficients (NRC) of all Hinoki cypress cubes were 0.41-0.59. Thus, this research found that Hinoki cypress cubes have a sound-absorbing function.

Investigation of Sound Absorption Ability of Acanthopanax senticosus Wastes

“…improving the sound absorption effect depending on the increase in thickness. This trend is typical of porous or granular sound-absorbing materials (Jang, 2022b(Jang, , 2022c(Jang, , 2022dJang and Kang, 2021c).…”

“…However, the thickness of the 1,000 Hz (Voronina and Horoshenkov, 2004). This phenomenon is observed in most of granular type sound-absorbing materials (Jang, 2022b(Jang, , 2022c(Jang, , 2022dMaderuelo-Sanz et al, 2014;Vašina et al, 2006).…”

“…The sound absorption coefficients of A. senticosus wastes were evaluated using an impedance tube (type 4206, Brüel & Kjaer, Naerum, Denmark) designed in accordance with the ISO 10534-2 (International Organization for Standardization, 2001) same as the author's previous studies (Jang, 2022b(Jang, , 2022c(Jang, , 2022d. A. senticosus wastes were filled to a height of 40, 60, 80, and 100 mm in two different impedance tubes with diame-Fig.…”

“…The values of the sound absorption coefficients at 250, 500, and 1,000 Hz were collected from the 99 mm diameter impedance tube, and those at 2,000 Hz were collected from the small-diameter impedance tube (Jang, 2022b(Jang, , 2022c(Jang, , 2022d.…”

“…Wood and forest-by products have been suggested as a natural sound-absorbing materials (Iswanto et al, 2020;Jang, 2022aJang, , 2022bJang, , 2022dJung et al, 2020;Jung et al, 2021). Previous studies have reported that the pore structure of wood has a sound-absorbing effect (Jang and Kang, 2021a, 2021dJiang et al, 2004;Taghiyari et al, 2014).…”