• Title/Summary/Keyword: sound effect

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Effectivness and Sound Field Analysis of Top Sections of Noise Barriers for High-speed Railway Lines (고속철도 구간 방음벽 상단 형상에 의한 음장 해석 및 효과)

  • Koh, Hyo-In;Han, Hwan-Su
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.135-138
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    • 2005
  • On the basis of theoretical studies on the effect of the cylinders attached to semi-infinite screens, the effect of the tangential sound power-transport along the cylindrical top section of noise barriers is studied. Four types of acoustical mechanism between the surface of the cylinder and the adjacent air particles are investigated, namely Z $\rightarrow$ $\infty$, Z $\rightarrow$ pc, Z $\rightarrow$ 0 and actively controlled surface sound field. In active control case the sound power parallel to the surface of the attached cylinder is minimized by means of a secondary sound field, which is generated from a part of the attached cylinder. In each case the change in the acoustical shadow zone was shown and compared. The numerical study shows the possibility of deflecting the incident sound by minimizing the acoustical surface impedance of the upper sections.

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Experimental Study on the Noise Reduction of Drainage Pipe by a kind of Curve Pipe (곡관 종류에 따른 배수관내의 소음 저감에 관한 실험적 연구)

  • Kim, Jeong-Hoon;Shim, Dong-Hyouk;Kim, Kyoung-Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.11a
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    • pp.187-192
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    • 2006
  • The effect where the multiple sound arrest ing goes mad to the human being does the zone. From like that cotton, this dissertation the both sides flag executed the research regarding a sound arresting reduction in the object in one example. It compared the piping structure which generally is space-time and a specific piping structure and it tested and research and the modeling regarding a sound arresting reduction the simulation which leads and it executed result and comparison of existing it analyzed. The duplication where the reduction effect is bigger the result general VG2 piping structure than escape it did with the fact that it appears the large effect the piping structure which it connects. Also, the straight pipe effect of multiple sound arresting could not go mad with the fact that.

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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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    • 2001.11a
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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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Effect of surface etching and ultrafine fibers on sound absorption characteristics

  • Lee, Yun-Eung;Seon, Choe-Hwa;Su, Baek-Mun;Hwan, Ju-Chang
    • Proceedings of the Korean Fiber Society Conference
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    • 1998.10a
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    • pp.406-409
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    • 1998
  • Sound absorbing materials are divided into several types according to the appearances and the characteristics. Basic mechanism of sound absorption in various sound absorbing materials is the conversion of sound energy into hat energy. Here the important elements which govern by the conversion from sound into heat depend on the type of materials. (omitted)

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Sound Source Localization using Acoustically Shadowed Microphones (가려진 마이크로폰을 이용한 음원 위치 추적)

  • Lee, Hyeop-Woo;Yook, Dong-Suk
    • Speech Sciences
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    • v.15 no.3
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    • pp.17-28
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    • 2008
  • In many practical applications of robots, finding the location of an incoming sound is an important issue for the development of efficient human robot interface. Most sound source localization algorithms make use of only those microphones that are acoustically visible from the sound source or do not take into account the effect of sound diffraction, thereby degrading the sound source localization performance. This paper proposes a new sound source localization method that can utilize those microphones that are acoustically shadowed from the sound source. The experiment results show that use of the acoustically shadowed microphones, which receive higher signal-to-noise ratio signals than the others and are closer to the sound source, improves the performance of sound source localization.

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Estimation Method of Noise Reducing Devices Installed on the Noise Barrier(I) - Estimation by Sound Intensity - (방음벽 상단소음저감장치의 성능평가 방법에 관한 연구(I) - 음향인텐시티에 의한 평가 -)

  • Kim, Chul-Hwan;Chang, Tae-Sun;Lee, Ki-Jung;Kang, Hee-Man;Lee, Soo-Il;Chang, Seo-Il;Kim, Bong-Seok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.05a
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    • pp.1053-1056
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    • 2007
  • The acoustical performance of noise reducing devices installed on the top of a noise barrier were tested by small-scale outdoor tests. Noise measurements before and after installation of the devices were carried out using sound intensity methods. It is well known that the sound intensity method can specify the strength and directivity of sound, and it is convenient to consider the feature of sound around a noise barrier. The noise reduction effect of each edge device was evaluated using the difference between the input and output sound power levels calculated from sound intensities. It was investigated that each device had different efficiency in the shadow zone, while there was no significant difference between edge devices in the illuminated zone.

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A Study on the improvement of reverberation characteristics using tapped and nested-allpass delay line (Tapped and nested-allpass delay line을 이용한 잔향특성 개선에 관한 연구)

  • Yoon, Jae-Yeun;Park, Jun-Sun;Jin, Yong-Ok
    • Journal of Broadcast Engineering
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    • v.12 no.1 s.34
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    • pp.28-40
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    • 2007
  • In this paper, we proposes an idea for improved sound characteristic which decreasing a problem in previous reverberation algorism structure. To later reflection sound, proposed new reverberation structure, using a lopped and nested all-pass delay line, and it is designed to improve an natural concert hall sound. In addition, In order to have best imaginary sound effect, we extracted the factors by controlling each delay line's delay time, and we realized a proposed new algorithm by using general-purpose DSP. Through several experimental cases, we observed better effect on improvement of linear flatten and reverberation density and decreasing about colorlessness and non-linear sound at previous proposed model about impulse input.

The Forward Prediction of Radiation Sound Field Using Acoustic Holography : Basic Theory and Signal Processing Method (음향 홀로그래피를 이용한 방사 음장의 전방예측 방법에 관한 기본 이론 및 신호처리 방법)

  • 김양한;권휴상
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.9
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    • pp.1654-1668
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    • 1992
  • The acoustic field resulted by the radiation of sound from vibrating structure is predicted based on the sound pressure measurements. The sound pressures are measured at discreate point on the measurement plane ; Hologram. Based on these discreate measurements, the sound field away from the acoustic source is constructed based on the discreate form of Kirchhoff-Helmohltz integral equations The velocities, intensities, and pressures of arbitrary plane of interest in space are predicted and visualized The effects on the sound field reconstruction ; finite aperture effect, effect of finite sampling interval in space studied in terms of wraparound error and spatial aliasing. Numerical simulations and experimental verifications are performed to see these effects. To reduce the wraparound error, zero padding technique in space is used and the usefulness of the method is demonstrated by various examples.

Sound Quality Evaluation for Laundry Noise by a Virtual Laundry Noise Considering the Effect of Various Noise Sources in a Drum Washing Machine (소음원의 영향이 고려된 가상 세탁음 제작을 통한 드럼 세탁기의 음질 인덱스 구축)

  • Jeong, Jae-Eun;Yang, In-Hyung;Fawazi, Noor;Jeong, Un-Chang;Lee, Jung-Youn;Oh, Jae-Eung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.6
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    • pp.564-573
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    • 2012
  • The objective of this study is to determine the effect for the sound quality according to the noise source and to build the sound quality index of the laundry noise. In order to compare laundry noise among the influence of noise sources, we made virtual laundry noises by synthesizing an actual laundry noise and each noise source such as a dropping noise, water noise, motor noise and circulation pump noise. We conducted a listening test by customers using virtual laundry noises. As a result of listening test, we found that the dropping noise has a decisive effect on the sound quality of the laundry noise. We conducted the multi regression analysis of sound quality for the laundry noise using the statistical data processing. It is verified to the reliability of the multi regression index by comparison with listening results and index results of other actual laundry noises. This study is expected to provide a guide line for improvement of the laundry noise.

Density Profile and Sound Absorption Capability of Ceramics Manufactured from Sawdust, Chaff and Charcoal: Effect of Carbonization Temperature and Mixing Ratio

  • Jung-Woo HWANG;Seung-Won OH
    • Journal of the Korean Wood Science and Technology
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    • v.52 no.3
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    • pp.234-242
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    • 2024
  • In this study, the effect of carbonization temperature and mixing ratio of ceramics manufactured from sawdust, chaff and charcoal on sound absorption performance and density profile was investigated. The density profile of ceramics prepared by the addition rates of sawdust, chaff and charcoal showed the highest value at 91.00% when the ratio of sawdust, chaff and charcoal was 50:25:15. However, the difference in density profile according to the addition rate was insignificant. The density profile of ceramics manufactured according to the carbonization temperature showed the highest value of 88.06% when manufactured at 800℃. However, it does not show any particular trend, so it is understood that the effect of the carbonization temperature on the density gradient is small. On the other hand, the sound absorption coefficients of ceramics prepared by the addition rates of sawdust, chaff and charcoal is between 0.3 and 0.4 at almost all frequencies when the addition rates of sawdust, chaff and charcoal are 50:30:10 and 50:35:5, respectively. Therefore, as the chaff particles increased, the sound absorption performance was improved. In addition, the sound absorption coefficients of the ceramics manufactured at each carbonization temperature showed the highest value in the ceramics manufactured at 1,200℃.