• 제목/요약/키워드: Sound Source

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히스 노이즈제거를 통한 아날로그의 디지털 복원에 대한 연구 - X-NOISE를 활용한 히스 노이즈리덕션을 중심으로 - (A Research on the Digital Restoration of the Analog by Removing Hiss Noise (Using X-NOISE Based on Hiss-Noise Reduction))

  • 변정민;두일철
    • 디지털산업정보학회논문지
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    • 제10권4호
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    • pp.161-170
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    • 2014
  • Analog cassette tapes are easily changed due to environmental factors. To digitize is the best way to preserve a sound source. The way to digitize is to deal with the original sound to be enhanced to a variety of sources by playing through the audio card after recording. In this process to occur, it's the most important to remove various noise and equalizing sound in a method for preserving. It's studied about how to remove noise by using one of softwares, Cubase 5. 5, to remove hiss noise, which happens changing analog tape into digitalization. A amount of hiss noise is reduced to use X-Noise software of Wave which uses in Cubase 5.0, one of PLUG-IN. The noise is removed changing value of threshold and reduction every 10 times in no change of origin sound. To keep regular condition, the experiment to remove the hiss noise is conducted based on sound meondle, which is one of sound Nonmaegi. The noise is removed easily when the value of threshold is getting high in spite of giving a little value of reduction. However, as it gives a amount of reduction high, the damage rate of the sound source gets high.

풍동 조건의 마이크로폰 어레이 측정에서 전단층 보정에 관한 연구 (Study on Shear Layer Correction of Microphone Array Measurement in the Wind Tunnel Test)

  • 김위준;이욱;최종수
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2007년도 추계학술대회논문집
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    • pp.92-96
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    • 2007
  • Microphone array beamforming method has been recognized as an important aeroacoustic research field and become a standard technique in localizing sound sources. This method also used in flight acoustic measurement, and especially, it is very useful when measure sounds inside the wind tunnel. In measuring sound which is inside the wind tunnel by traditional beamforming method, there are some errors caused by airstream. The speed and the propagation path of the sound changes as it travel through the airstream. This makes the error which the position of sound is changed a little bit to the down stream direction. In this paper, validation test has made about the correction equation for this wind effects of previous researches. And beamforming including shear layer correction was performed about a sound source in the anechoic open-jet windtunnel.

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아파트에서 고체음의 부파성상에 관한 연구 (A Study on the Propagation Characteristics of Solid-Borne Sound in Apartment Building)

  • 김영완;박병진
    • 한국음향학회지
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    • 제5권4호
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    • pp.5-15
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    • 1986
  • This pater is a study on the measurement of solid-borne sound propagation in buildings. The purpose of this paper is to present the data needed for comfortable building enevironment. Solid-Borne sound in apartment building was measured at the source of sound and at many receiving locations in building. Dispersion of the sound level was analyzed to understand noises level at different locations. Graphic method as well as polynomial regression techniques were employed. For this experiment, we made use of the TAPPING MACHINE according to the standard rules of ISO as a impulse exciter, and the measurement was carried out after the building has been all completed. Noticeable noise reductions were observed as the distance from the source to the receiving location increases.

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잔향시간지표를 이용한 나무의 음향확산성 평가 (Using reverberation time to evaluate the amount of scattered sound energy from a tree)

  • 양홍석
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2014년도 춘계학술대회 논문집
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    • pp.141-144
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    • 2014
  • In urban spaces surrounded by buildings, trees could disperse sound energy, which affect sound level distribution and street canyon reverberation. Therefore, this paper examines the amount of scattered sound energy from a tree in open field by means of a reverberation time (RT). Five trees of different species and crown sizes were considered. The influential factors include crown size and shape, foliage condition, and source-receiver distance. The results show that RT is proportionally increased with the increase of tree crown sizes, which is the most determining factor. The maximum RT measured was 0.34 sec at 4000 Hz for the studied trees in leaf. The presence of leaves increased RT at high frequencies, typically by 0.14 sec at 4000 Hz. With increasing source-receiver distance within 40 m, RT was slightly changed.

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소음계 교정 자동화 시스템 개발 및 성능평가 (Development and Performance of Automated Calibration System of Sound Level Meters)

  • 김용태;조문재;이용봉;서재갑
    • 소음진동
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    • 제8권5호
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    • pp.879-886
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    • 1998
  • An automated calibration system of sound level meters was developed and tested. As a standard sound source, the speaker unit(Forstex FE208) cabineted by 440$\times$390$\times$490 $\textrm{mm}^3$(LHW) volume wood box was adopted. Including this source, the driving part was found out to have a good linearity of sound pressure output vs AC voltage input. The Hybrid-Bisect/Newton-Raphson method modified by the linearity was adopted as a searching algorithm. Uisng GPIB interface, the console PC make the control, measurements, and calculations and finally make the accumulation of useful data and results automatically by the instructon in the program coded by C languate. Several trials of automatic calibration using this developed system give the reliable results.

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풍동 조건의 마이크로폰 어레이 측정에서 전단층 보정에 관한 연구 (Study on Shear Layer Correction of Microphone Array Measurement in the Wind Tunnel Test)

  • 김위준;이욱;최종수
    • 한국소음진동공학회논문집
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    • 제18권6호
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    • pp.612-618
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    • 2008
  • Microphone array beamforming method has been recognized as an important aeroacoustic research field and become a standard technique in localizing sound sources. This method also used in flight acoustic measurement, and especially, it is very useful when measure sounds inside the wind tunnel. In measuring sound which is inside the wind tunnel by traditional beamforming method, there are some errors caused by airstream. The speed and the propagation path of the sound changes as it travel through the airstream. This makes the error which the position of sound is changed a little bit to the down stream direction. In this paper, validation test has made about the correction equation for this wind effects of previous researches. And beamforming including shear layer correction was performed about a sound source in the anechoic open-jet wind tunnel.

주거 공간내 공조기 소음의 전달 경로에 관한 연구 (A Study on the Sound Paths of Air-conditioner in House)

  • 최진권;손진희;장서일;이진교;김진섭
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2001년도 추계학술대회논문집 I
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    • pp.522-528
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    • 2001
  • This study was conducted to determine the sound paths and transmitted sound level in house. An air-conditioner system was selected a typical sound source. The measured transmission loss data shows that the apertures have an significant effect on the transmitted noise and comparable with the existing theoretical data. Therefore the complex aperture was substitute to quantitative apertures approximately. An effective simulation method, ray tracing and mirror image source method, was employed in the prediction of transmitted sound level. The measured results were reflected on the simulated results.

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능동음원 및 벽면 어드미턴스의 재구성을 통한 실내 소음원의 정확한 규명 방법 (Identification of Interior Noise Sources by Using Reconstruction of Active Sources and Surface Admittance)

  • 김영기;김양한
    • 소음진동
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    • 제8권3호
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    • pp.435-440
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    • 1998
  • The main objective of this study is to estimate location and strength of sound sources distributed on the surface of an enclosure. Acoustic holography method has been used to identify the sources in an interior sound field. However, it can not completely distinguish between the direct sound field from sources and the reflections from surfaces. The method just reconstructs the entire sound field based on the sound pressure at the finite number of measurement points. In this stduy, a method which estimates only the active sources by using measurements of field pressure and surface admittance is proposed. An in-situ technique to estimate the general boundary condition is also proposed by using acoustic holography, assuming the surfaces are locally reacting.

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공기조화 취출구 소음 평가를 위한 물리지수 분석 (Analysis of Physical Parameters for the Evaluation of HVAC Diffuser Noise)

  • 박현구;김항;고성석;김선우
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2006년도 춘계학술대회논문집
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    • pp.402-405
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    • 2006
  • The diffuser noise of HVAC(heating ventilating and air-conditioning) uses dB(A) or NC as a indoor noise criteria that ASHRAE represents, and there is no specific guide line for application. According to the previous study, there are some problems like that even though the sound level of sound source is same, the NC shows different values, which makes the noise rating confused. This problem is caused by the frequency characteristics of sound source and its sound level. Therefore, appropriate evaluation method should be considered based on the subjective responses. This study aims to analyze the physical parameters appropriate for the evaluation of HVAC diffuser noise. To achieve this, recording of sound sources, calculation of physical parameters and psycho-acoustic experiment were carried out and the results were derived from the correlation analysis between physical parameters and subjective evaluatio

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2차원적 음원추적에 관한 연구 (A Study on 2-Dimensional Sound Source Tracking System)

  • 문성배;전승환
    • 한국항해학회지
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    • 제20권4호
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    • pp.71-79
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    • 1996
  • When navigating in or near an area of restricted visibility, it is necessary to be heard the whistle, bell and/or the siren of lighthouses or ships at times. Even though we can get the brief informations about the property of sound, the direction and range of a sound radiator, it is not enough to get the accurate informations for decision making. Generally the audio frequency is known as 16~20, 000Hz, but the earshot is shorten and discrimination of sound is more difficult when there is some noise. The sound pressure is 60dB at the moment when human speaks 1 meter away. Usually the noise pressures are 40dB in a silent room and 60dB on the quiet street, respectively. It this study, the basic algorithm and a method of signal processing are suggested to trace the direction and range of the source radiator using the signals received through not a physical sense but the microphone sensors.

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