• Title, Summary, Keyword: Sound characteristics

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Sound Absorption Characteristics of Building Interior Decoration Materials (건축내장재의 흡음 특성)

  • Kang, Dae-Joon;Lee, J.W.;Gu, J.H.;Park, H.K.
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.3
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    • pp.201-206
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    • 2007
  • It is important to consider the sound absorption characteristics of building interior decoration materials when we design a building and simulate acoustics in a room. The purpose of this study is to accumulate acoustic data on building interior decoration materials and give a basic data for improving the sound absorption performance by testing the sound absorption coefficients of 9 types of ceiling materials, 14 types of wall papers and 20 types of floor papers.

Sound Quality Analysis for Axle-Gear Whine Sound (액슬 와인 음질에 대한 연구)

  • Kim, Tae-Gyu;Lee, Sang-Kwon;Jo, Yun-Kyoung;Kim, Jong-Youn
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.141-146
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    • 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.

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A Study on the Propagation Characteristics of Fire Alarm Sound in Buildings (화재비상경보음의 건물 내 전달특성에 관한 연구)

  • Baek, Eun-Sun
    • Fire Science and Engineering
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    • v.23 no.5
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    • pp.153-160
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    • 2009
  • This study aims to review the propagation characteristics of fire alarm sound in building through computer simulation. In order to achieve this goal, the sound power level of existing three different emergency alarms were measured in an anechoic chamber. Sound power level of alarm bell was 98.6dB and electronic-siren speaker was 95.7dB, and electronic-siren phon was 101.8dB at the voltage of DC 24V in the condition of anechoic chamber. As the results of acoustic simulation, it was shown that sound levels at the corridor of the building were relatively high and even. But, there were large difference in sound level at all the frequency bands between corridor and lecture rooms. This mean that alarm sound couldn't be recognized sometimes in lecture rooms. Through the computer simulation, the propagation characteristics of fire alarm sound could be forecasted and compared due to plans of buildings.

Enhancement of the 3D Sound's Performance using Perceptual Characteristics and Loudness (지각 특성 및 라우드니스를 이용한 입체음향의 성능 개선)

  • Koo, Kyo-Sik;Cha, Hyung-Tai
    • Journal of Broadcast Engineering
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    • v.16 no.5
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    • pp.846-860
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    • 2011
  • The binaural auditory system of human has ability to differentiate the direction and the distance of the sound sources by using the information which are inter-aural intensity difference(IID), inter-aural time difference(ITD) and/or the spectral shape difference(SSD). These information is generated from the acoustical transfer of a sound source to pinna, the outer ears. We can create a virtual sound system using the information which is called Head related transfer function(HRTF). However the performance of 3D sound is not always satisfactory because of non-individual characteristics of the HRTF. In this paper, we propose the algorithm that uses human's auditory characteristics for accurate perception. To achieve this, excitation energy of HRTF, global masking threshold and loudness are applied to the proposed algorithm. Informal listening test shows that the proposed method improves the sound localization characteristics much better than conventional methods.

A Study on the Floor-Specific Characteristics of Road Traffic Noise in Apartment Buildings (공동주택의 층별 도로교통 소음의 전달 특성에 관한 연구)

  • Ham, Jin-Sik
    • Journal of the Korean housing association
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    • v.19 no.1
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    • pp.1-8
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    • 2008
  • This study is an attempt to understand the floor-specific characteristics of facade road traffic noise in apartment buildings. For this purpose, it sampled a total of seven roadside apartment building complexes: three with no soundproof bar barrier installed at roadside, one with a forest buffer zone, one with a sound-absorbing hill, and two with soundproof barriers. The measured noise level was highest on the 5th floor of apartment buildings with no soundproof barrier, and the upper stories from the 5th floor showed lower-noise measurements in order. For apartment buildings with soundproof barriers, however, the noise level was lower on the 10th floor than the 5th floor. Two apartment building groups--one with a sound-absorbing hill and the other with no soundproof barrier--showed similar measurement results in the floor-specific characteristics of facade road traffic noise. This suggests that such installations have little sound insulation effect. In the apartment building complex with a forest buffer zone around it, a slight sound insulation effect was measured on the lower floors of the buildings.

An acoustical characteristics of sound proof panel for high speed train (고속전철용 방음패널의 음향특성 평가)

  • 서재갑;정성수;서상준;조문재;나희승;양신추
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.145-149
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    • 2001
  • In this study, an acoustical characteristics of sound proof panel for high speed train was performed. A sound absorption coefficient and transmission loss of sound proof panels for high speed train were tested in reverberation chambers and compared those of ordinary sound proof panel. The effect of noise barrier was simulated by using ray noise program with measured sound absorption coefficient for high speed train case and for ordinary case.

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Recognition of the Direct and Reflected Sounds in an Irregulary Formed Chamber (비정방형실내에서의 직접음과 반사음 식별에 관한 연구)

  • 차일환;박규태;임광호
    • The Journal of the Acoustical Society of Korea
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    • v.2 no.1
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    • pp.11-19
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    • 1983
  • An irregulary formed chamber was designed and constructed to recognize the direct sound radiated from the sound source and the reflected sound from the walls of the chamber. The sound signal used was tone burst in the frequency response characteristics with the signal detection after transient effect. The direct wave, transient phenomena and the primary reflected sound could be asiily distinguished each other by measurements of the arrival time of the time difference. And also noise could be easily distinguished by the same method. The result obtained can be used in industries for automatic measurement of the sound pressure reponse characteristics with respect to frequencies.

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Acoustic Properties of Solid Materials: Sound Speed, Transmission Coefficient, and Attenuation

  • Roh Heui-Seol;Lee Kang Il;Jung Kyung-Il;Yoon Suk Wang
    • Proceedings of the Acoustical Society of Korea Conference
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    • pp.525-528
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    • 2002
  • The speed of sound, transmission coefficient, and attenuation are measured around the center frequency 1 and 2 MHz in solid materials such as bone, sediment, rubber, and Lucite materials. Common and different characteristics of such materials in the sound speed, transmission coefficient, and attenuation are discussed. Ambiguities in estimating such acoustic characteristics we also addressed. Ultrasonic properties of the first and second kind waves are clarified for different materials. Discussions are concentrated on classes of sound speed, broadband ultrasonic attenuation (BUA), and correlations of sound speed and BUA with apparent density. New correlations of inverse sound speed square and BUA with apparent density are suggested.

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Relationship between Characteristic Parameters of Rustling Sounds and Mechanical Properties of Fabrics (직물이 스치는 소리의 특징 파라미터와 직물의 역학적 성질간의 관계)

  • 조길수;이은주
    • Textile Science and Engineering
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    • v.36 no.5
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    • pp.403-410
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    • 1999
  • In order to investigate the relationship between the characteristics of fabric rustling sounds and the mechanical properties of fabrics, the rustling sounds of 18 selected fabrics were produced and recorded by the sound generator developed for this study. The sounds recorded were analysed in the forms of sound spectra presented in terms of sound pressure and frequency through FFT analysis. Sound spectrum of each specimen was fitted by Autoregression (AR). Coefficients of the functions were considered as characteristic parameters of the sound of specimens. Mechanical properties of specimens were measured by KES-FB. Relationship between characteristic parameters of fabric sounds and mechanical properties was investigated by correlation coefficients and linear regression. Tensile linearity (LT), shear stiffnesss (G), and shear hysteresis (2HG, 2HG5) showed significant positive correlations with $\alpha$, an AR parameter related mainly to sound loudness of fabric rustles. Through linear regression, the shear hysteresis (2HG) proved to be the most powerful property with relation to characteristics of fabric rustling sounds parameter ($\alpha$).

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Analysis of Acoustic Psychology of City Traffic and Nature Sounds (도심 교통음과 자연의 소리에 대한 음향심리 분석)

  • Kyon, Doo-Heon;Bae, Myung-Jin
    • The Journal of the Acoustical Society of Korea
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    • v.28 no.4
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    • pp.356-362
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    • 2009
  • In modern society, most people of the world are densely populated in cities so that the traffic sound has a very significant meaning. people tend to classify traffic sound as a noise pollution while they are likely to categorize most nature sound as positive. In this paper, we applied various forms of FFT filters into white noise belonged in nature sound to find frequency characteristics of white noise which preferred by people and confirm its correlation with nature sound. In addition, we conducted an analysis through the comparison of various traffic and nature sound waveforms and spectra. As a result of analysis, the traffic sound have characteristics which sound energy had concentrated on specific frequency bandwidth and point of time compared to nature sound. And we confirmed the fact that these characteristics had negative elements to which could affect to people. Lastly, by letting the subjects listen directly to both traffic and nature sound through brainwave experiment using electrode, the study measured the energy distribution of alpha waves and beta waves. As a result of experiments, it has been noted that urban sound created a noticeably larger amount of beta waves than nature sound; on the contrary, nature sound generated positive alpha waves. These results could directly confirm the negative effects of traffic sound and the positive effects of nature sound.