• Journal of the Korean Wood Science and Technology
• /
• 제46권4호
• /
• pp.338-345
• /
• 2018

The sound insulation capacity of a barrier is indicated by its transmission loss. In this study, the sound transmission loss of a sound barrier filled with rice-straw particles was measured by the transfer function method and a laboratory measurement method. The results of the two measurements were compared. The transmission losses measured by the two methods were similar above a frequency of 500 Hz. The loss increased greatly upon the introduction of a plywood to the sound barrier. The results of this study are expected to be used to design sound barriers for roads.

• The Journal of the Acoustical Society of Korea
• /
• 제15권4E호
• /
• pp.3-8
• /
• 1996

The bubble size distribution is critical information to understand sound propagation and ambient noise in the ocean. To estimate the bubble size distribution in a bubbly water, the sound attenuation has been only in the conventional acoustic bubble sizing method without considering the sound speed variation. However, the effect of the sound speed variation in bubbly water cannot be neglected because of its compressibility variation. The sound attenuation is also affected by the sound speed variation. In this paper, a coherent acoustic bubble sizing inverse technique is introduced as a new bubble sizing technique with considering sound speed variation as well as the sound attenuation. This coherent sizing method is theoretically verified with the bubble distribution functions of single-size, Gaussian, and power-law functions. Its numerical test results with the coherent acoustic bubble sizing method show good agreement with the given bubble distributions.

• 한국소음진동공학회논문집
• /
• 제15권5호
• /
• pp.558-563
• /
• 2005

This research aims to derive the general emotion and preference of the 25 sounds by using the questionnaire method to provide the contents for the soundscape design fit to the characteristics of the given situation. The results can be summarized as follows : Nature sounds except dog barking and locust crying showed highest preference, and the traffic sounds, baby crying and footstep of upper floor showed the lowest. Hereby, the sound recognition can be different each other according to quality of tone and situation even they are the same sounds. The most impressive, wanted to be conserved and retrospective sound was the nature sound, and the most wanted to be removed sound was the machinery sound. And the social sound was shown as the most korean and fit to the art theme street.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2004년도 추계학술대회논문집
• /
• pp.806-809
• /
• 2004

This research aims to derive the general emotion and preference of the 25 sounds by using the questionnaire method to provide the contents for the soundscape design fit to the characteristics of the given situation. The results can be summarized as follows; Nature sounds except dog barking and locust crying showed highest preference, and the traffic sounds, baby crying and footstep of upper floor showed the lowest. Hereby, the sound recognition can be different each other according to quality of tone and situation even they are the same sounds. The most impressive, wanted to be conserved and retrospective sound was the nature sound, and the most wanted to be removed sound was the machinery sound. And the social sound was shown as the most korean and fit to the art theme street.

• Journal of the Korean Wood Science and Technology
• /
• 제50권5호
• /
• pp.365-374
• /
• 2022

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.

• 한국소음진동공학회논문집
• /
• 제22권12호
• /
• pp.1172-1183
• /
• 2012

Aure's tonality was considered as the sound metrics for the expression of the tonality of gear whine sound in a previous research. It was failed to use the Aure's tonality as a sound metric for the tonal impression. Thus Aures's tonality, was developed for tonal impression in previous research. However, this metric did not express well the tonality of gear whine sound since the whine sound is a non-stationary signal with frequency modulation and amplitude modulation. In this study, the new method for the tonality evaluation for a non-stationary signal is presented. It is developed based on the prominence ratio, tonality impression function, and lower threshold level. It improves the accuracy and reliability of the sound quality index being used for the sound quality evaluation of the axle-gear whine sound.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 춘계학술대회논문집
• /
• pp.141-146
• /
• 2007

A gear whine sound due to the axle system is one of the most important sound qualities in a sport utility vehicle (SUV). In the previous research about the gear whine sound, it was known that it is difficult to evaluate the gear whine sound objectively by using the only A-weighted sound pressure level because of the masking effect. In this paper, for the objective evaluation of the axle-gear whine sound, the characteristics of the axle-gear whine sound is at the first investigated based on the synthetic sound technology and the new objective evaluation method for the axle-gear whine sound is developed by using the sound metrics, which is the psychoacoustics parameters, and the artificial neural network (ANN) used for the modeling of the correlation between objective evaluation and subjective evaluation.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2013년도 추계학술대회 논문집
• /
• pp.519-524
• /
• 2013

The purpose of this study is that developing the index which evaluate sound quality of door latch and improving its sound quality through that results. For that, various operating sound of door latch was used for jury test. Loudness and sharpness related metrics are dominant in sound quality index we developed. This research investigate the main transfer path of its operating sound through sound field visualization and get conclusion that could reduce the impact sound of door latch. Therefore, we could verify sound quality improvement of modified product by using sound quality index.

• 복합신소재구조학회 논문집
• /
• 제7권1호
• /
• pp.19-24
• /
• 2016

Most of the soundproof tunnels generate significant discharge noise through their inlets and outlets so that the length of the tunnel has been extended frequently than required to minimize the effect on such discharge noise. Thus, in this paper, we investigate reduction capability of discharge noise from the sound proof tunnel installed with lateral sound-absorbing panels on the partitioned truss members in the longitudinal direction of the tunnel. In conclusion, noise field analysis results shows that the sound proof tunnels with lateral sound-absorbing panels have an effect on discharge noise abatement and thereby tunnel's length reduction.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제6권4호
• /
• pp.894-903
• /
• 2014

Insertion loss prediction of large acoustical enclosures using Statistical Energy Analysis (SEA) method is presented. The SEA model consists of three elements: sound field inside the enclosure, vibration energy of the enclosure panel, and sound field outside the enclosure. It is assumed that the space surrounding the enclosure is sufficiently large so that there is no energy flow from the outside to the wall panel or to air cavity inside the enclosure. The comparison of the predicted insertion loss to the measured data for typical large acoustical enclosures shows good agreements. It is found that if the critical frequency of the wall panel falls above the frequency region of interest, insertion loss is dominated by the sound transmission loss of the wall panel and averaged sound absorption coefficient inside the enclosure. However, if the critical frequency of the wall panel falls into the frequency region of interest, acoustic power from the sound radiation by the wall panel must be added to the acoustic power from transmission through the panel.