• Title, Summary, Keyword: Sound characteristics

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The evaluation of Sound Power Level and development of index for Sound Quality of Vacuum Cleaner according to performances of Sound Absorbtion Materials (흡음재 성능에 따른 진공청소기의 음향파워 평가 및 음질인덱스 개발)

  • Kwon, Hyuk-Je;Lee, Sang-Kwon;Gu, Jin-Hoi;Lee, Hyun-Ho
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.112-120
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    • 2008
  • Today, the use of a vacuum cleaner gave us the higher quality of life than past time, but sometimes made us w1comfortable in the house because of the specific noise that is annoying. So we need to study how sound absorbtion materials affect sound power level and sound quality with sound metrics. In this paper, we will measure and calculate sound power level for vacuum cleaner and analyze characteristics of the noise for 10 Signals according to materials positioned in vacuum cleaner. The multiple regression analysis can estimate the nonlinear characteristics of relation between subjective evaluation and sound metrics. So we will develop sound quality index for vacuum sound.

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Sound Characteristics and Hand of Fabrics for Blouse (블라우스용 직물의 소리 특성과 태)

  • 이은주;조길수
    • Journal of the Korean Society of Clothing and Textiles
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    • v.24 no.4
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    • pp.605-615
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    • 2000
  • This study was carried out to investigate sound characteristics including sound parameters and subjective sensation, and primary hand values related with sound of fabrics for blouse, and furthermore to predict subjective sound sensation with mechanical properties and sound parameters. Sound of specimens was analyzed by FFT. Level pressure of total sound(LPT), loudness(Z), coefficients of autoregressive(AR) functions for fitting the spectra, and sound color factors(ΔL and Δf) were obtained as sound parameters. Primary hand values for women's thin dress were calculated by using KES-FB. Subjective sensation for sound including softness, loudness, sharpness, clearness, roughness, highness, and pleasantness was evaluated by free modulus magnitude estimation. The results were as follows; 1. Fabrics for blouse showed similar spectral shapes to one another in that amplitude values were lower in most ranges of frequencies than fabrics for other uses. 2. It was found that fabrics for blouse were less louder because LPT, loudness(Z), and ARC values were lower than other fabrics. 3. Primary hand values indicated that specimens were soft-touched, flexible, and less crisp. Among primary hands related with sound, Shari values were higher for silk fabrics than for synthetic ones, while the values for Kishimi were similar, 4. Fabrics for blouse were rated more highly for softness, clearness, and pleasantness than for loudness, sharpness. roughness, and highness. Silk fabrics were evaluated more pleasant than synthetic fabrics. 5. Subjective sensation for sound of blouse fabrics were predicted with mechanical properties and physical sound parameters.

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A Study on the Reduction Characteristics of Floor Impact Sound Insulation Due to the Ceiling Frame Structures in Apartment Houses (공동주택의 천장틀구조 변화에 따른 바닥충격음 차음특성 연구)

  • 정환욱;기노갑;송민정;김선우
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.8
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    • pp.573-580
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    • 2002
  • Generally the ceiling frame of apartment house is made of wood. But the wood frame has several problems due to the natural properties such as distortion by shrink, low fire resistance and material loss in the construction field. And it has some defections in sound insulation performance. Therefore it is necessary to develop a new method that can be used as a ceiling frame. This study aims to analyze and to compare the sound insulation characteristics against the floor impact sound between wood ceiling frame and M-bar frame which is made of steel. The results of this study are like these. M-bar frame is more effective than wood ceiling frame in sound insulation. And sound absorbing or sound insulation materials which can be Put on gypsum board are helpful to improve floor impact sound insulation performance.

Cross-Cultural Comparison of Sound Sensation and Its Prediction Models for Korean Traditional Silk Fabrics

  • Yi, Eun-Jou
    • Fibers and Polymers
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    • v.6 no.3
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    • pp.269-276
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    • 2005
  • In this study, cross-cultural comparison of sound sensation for Korean traditional silk fabrics between Korea and America was performed and prediction models for sound sensation by objective measurements including sound parameters such as level pressure of total sound (LPT), Zwicker's psychoacoustic characteristics, and mechanical properties by Kawabata Evaluation System were established for each nation to explore the objective parameters explaining sound sensation of the Korean traditional silk. As results, Koreans felt the silk fabric sounds soft and smooth while Americans were revealed as perceiving them hard and rough. Both Koreans and Americans were pleasant with sounds of Gongdan and Newttong and especially Newttong was preferred more by Americans in terms of sound sensation. In prediction models, some of subjective sensation were found as being related mainly with mechanical properties of traditional silk fabrics such as surface and compressional characteristics.

The Selection of the Scenery and Sound as the Environmental Friendly Elements (친환경 요소로서의 경관과 그에 어울리는 소리의 선택)

  • Kim, Hang;Jeon, Ji-Hyeon;Jang, Gil-Soo;Kook, Chan;Shin, Yong-Gyu
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.4
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    • pp.414-419
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    • 2006
  • In this research, the test how the evaluation of the spacial image influenced by the environmental friendly elements included in the visual information, and how the selection of the sound changed depending on the characteristics of spacial image were carried out by the 40 subjects. Vast tracts of green land and the waterfront were highly preferred and impressive than the other spaces. The green music, signal with water sound and bird chirping sound were highly scored. In the frequency characteristics of the factors, the first factor was artificial sound (high at the low frequency band), the second was natural sound(uniform at all frequency band) and the third was water sound (high at the middle and high frequency band over 500 Hz) . This shows that the proposal of the sound which has the frequency characteristics fit to the spacial image should be selected for the soundscape of the target space.

Sound Design System for Knitted Fabrics Using Sound Properties and Physiological Responses(I) -Sound Characteristics and Mechanical Properties of Weft Knitted Fabrics- (소리특성과 생리적 반응을 이용한 편성물의 소리디자인 시스템(I) -위편성물의 소리특성과 역학적 특성-)

  • Cho, Gil-Soo;Kim, Chung-Jeong
    • Textile Science and Engineering
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    • v.43 no.5
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    • pp.272-280
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    • 2006
  • This research aimed to analyze the mechanical properties and sound characteristics of weft knitted fabrics for establishing database of sound design system for knitted fabrics. The specimens consisted of 27 weft knitted fabrics. Mechanical properties of the knitted fabrics were measured with Kawabata evaluation system (KES). The frictional sounds of specimens were recorded by a sound generator and transformed into sound spectrum by FFT. The level pressure of total sound (LPT), level range ($\Delta$f), and frequency difference ($\Delta$f) were calculated from the sound spectra obtained in the FFT analysis. Zwicker's psychoacoustic parameters such as loudness(Z), sharpness(Z), roughness(Z), and fluctuation strength(Z) were calculated. The weft knitted fabrics have similar values of roughness(Z) and fluctuation strength(Z). Polyester fabrics with low elongation at maximum load (EM) and high coefficient of friction(MIU) showed the loudest and the sharpest frictional sound. The lyocell fabrics with low bending properties (B, 2HB) and thickness showed the most quiet and softest frictional sounds. Bending properties, surface properties, thickness and weight in weft knitted fabrics showed high relationship with the physical and psychoacoustic properties of frictional sound.

Sound Absorbing Characteristics According to Interior Configuration of Noise Barrier (흡음형 방음벽의 내부 구성에 따른 흡음특성)

  • 박진규;김상헌;김관주;박희준
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.387-392
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    • 2003
  • This study is put a focus on the identification of sound characteristics according to the interior configuration of sound absorption material and air gap. Noise barrier is general consists of front perforated panel, air layer, sound absorption material, air gap and back plate. Noise barrier is required to the NRC value of 0.7. The absorbing performance of the noise barrier relies on the opening ratio of the perforated panel and the efficiency of the absorbing material. This study has observed the effect of opening ratio and hole size, the increase of sound absorbing performance by the configurations of sound absorption material and air gap. New designed noise barrier is achieved the acoustical performance of 0.87 the measurement in a reveration room.

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Study on the Sound Radiaton Characteristics of Trains by Sound Intensity Method (음향 인텐시티법을 이용한 주행열차의 음향방사특성의 검토)

  • 주진수;김재철
    • Journal of KSNVE
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    • v.8 no.4
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    • pp.603-608
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    • 1998
  • In order to obtain basic data for the prediction of railway noise propagation, the noise radiation characteristics (source position, radiation directivity, etc) of trains were measured by using the sound intensity method. The measurements were performed at a side of railway by setting an intensity-probe array. As the measurement results, it was found that rolling noise due to interaction between wheel and rail and motor noise radiation from the lower part of train are dominant. The location of main sound sources can be described as being at the height of 0.1m in the center line of track, and the radiation directivity in the cross section of actually running trains are presented as a dipole source.

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Characteristics of Rustling Sound of Laminated Fabric Utilizing Nano-web (나노웹을 이용한 라미네이트소재의 마찰음 특성)

  • Jeong, Tae-Young;Lee, Eu-Gene;Lee, Seung-Sin;Cho, Gil-Soo
    • Fashion & Textile Research Journal
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    • v.15 no.4
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    • pp.620-629
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    • 2013
  • This study examines the rustling sound characteristics of electrospun nanofiber web laminates according to layer structures. This study assesses mechanical properties and frictional sounds (such as SPL); in addition, Zwicker's psychoacoustic parameters (such as Loudness (Z), Sharpness (Z), Roughness (Z), and Fluctuation strength (Z)) were calculated using the Sound Quality Program (ver.3.2, B&K, Denmark). The result determined how to control these characteristics and minimize rustling sounds. A total of 3 specimens' frictional sound (generated at 0.63 m/s) was recorded using a Simulator for Frictional Sound of Fabrics (Korea Patent No. 10-2008-0105524) and SPLs were analyzed with a Fast Fourier Transformation (FFT). The mechanical properties of fabrics were measured with a KES-FB system. The SPL value of the sound spectrum showed 6.84~58.47dB at 0~17,500Hz. The SPL value was 61.2dB for the 2-layer PU nanofiber web laminates layered on densely woven PET(C1) and was the highest at 65.1dB for the 3-layer PU nanofiber web laminates (C3). Based on SPSS 18.0, it was shown that there is a correlation between mechanical properties and psychoacoustic characteristics. Tensile properties (LT), weight (T), and bending properties (2HB) showed a high correlation with psychoacoustic characteristics. Tensile linearity (LT) with Loudness (Z) showed a negative correlation coefficient; however, weight (T) with Sharpness (Z) and Roughness (Z), and bending hysteresis (2HB) with Roughness (Z) indicated positive correlation coefficients, respectively.

Phase Characteristics of Approximated Head-related Transfer Functions(HRTFS) Using IIR Filters on the Sound Localization

  • Kanazawa, Kenichi;Hasegawa, Hiroshi;Kasuga, Masao;Matsumoto, Shuichi;Koike, Atsushi;Yamamoto, Hideo
    • Proceedings of the IEEK Conference
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    • pp.237-240
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    • 2000
  • We have proposed a simple method based on IIR filters for realizing sound image localization. How-ever the nonlinearity of phase characteristics of the IIR filters, which are used for sound image localization, cause decrease of the localization accuracy. In this paper we investigate the influence of phase characteristics on the sound localization. Head-related transfer functions (HRTFs) of a dummy-head are approximated by the IIR filter. We carried out sound image localization experiment with 2-loudspeaker reproduction using the approximated HRTFs. Then the errors which obtained from experiments were compared with the theoretical values which were estimated from the phase shifts of the IIR filters. As a result there was little influence of the nonlinear phase characteristics of the IIR fitters in the localization on the horizontal plane.

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