• Title/Summary/Keyword: Room acoustics

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Measurement of Short Reverberation Times of an Acoustic Room at Low Frequencies Using Wavelet Transform (웨이브렛 변환을 이용한 저주파에서 짧은 잔향 시간을 갖는 실음향에서의 잔향시간 측정에 관한 연구)

  • 이상권
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.1077-1080
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    • 2002
  • In building acoustics, reverberation time is an important acoustic parameter. However, it is often difficult to measure short reverberation times at low frequencies using the traditional band pass filter bank if the product of bandwidth (B) and reverberation time (T) is small. It is well known that the minimum permissible product of bandwidth and reverberation time of the traditional band pass filter is at least 16 [F. Jacobsen, J. Sound Vib. 115, 163-170 (1987)]. This strict requirement makes it difficult to measure short reverberation times of an acoustic room at low frequencies exactly. In order to reduce this strict requirement, recently, the wavelet filter bank is developed and the minimum permissible product of bandwidth and reverberation time is replaced with 4 [S. K. Lee, J, Sound Vib. 252, 141-153 (2002)]. In the present paper, it is demonstrated how the short reverberation times at low frequencies are successfully measured by using the wavelet filter bank. In order to present this job, two synthetic signals and one measured signal are used for impulse responses of an acoustic room.

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A Study on the Structural-acoustic Analysis Modeling Methods of the Room with Heavy Impact Noise Source (중량충격원 충격에 따른 공동주택 실내공간의 구조음장 해석 모델링방법에 관한 연구)

  • Lee, Jae-Kwang;Koo, Hae-Shik
    • KIEAE Journal
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    • v.9 no.6
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    • pp.81-87
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    • 2009
  • The purpose of the present study is to establish structural noise analyzing method for apartments building floor with structural-acoustic coupling analysis modeling. Noise through floor in the room is recognized as a significant problem with the consequence that noise isolation technique has been studied in the various fields of industry. From among noise factors, resonance sound is the main reason for solid noise of the floor, which is occurred by mechanical vibrations of the acoustic boundary line and the change of velocity. To analyse this phenomenon, numerical computation methods are provided in many fields, In this study, evaluation method for slab is established using finite element method, and a case study for analyzing acoustic phenomenon was suggested. The results show that numerical method, especially F.E.M, has a good approximation to predict noise at floors.

A Study on Improvement Effect of voice information transmission using Auralization at the hydraulic turbine dynamo room in Dam (가청화를 이용한 댐 수차 발전기실의 음성정보전달 개선효과에 관한 연구)

  • Kook, Joung-Hun;Ju, Duck-Hoon;Jung, Eun-Jung;Kim, Jae-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.263-267
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    • 2007
  • Even though Waterpower Generation as pollution-free has its own merit of contribution by supply of good quality electricity, due to the noise made at the time of its operation, a normal mutual communication among the workers and technicians engaging at the hydraulic turbine dynamo room is almost impossible, and since those finishing materials had been used mainly by reflection material, it is actual situation that when working for maintenance in the hydraulic turbine dynamo room, as counterpart's voice vibrates, its working efficiency is difficult to ensure. On such view point, this Research has conducted Psycho-acoustics Experiment about voice Definition using Auralizational Technique, on the object for the hydraulic turbine dynamo room that improved its acoustic performance by computer simulation. As the result of Study, it was known that the clearness of sound with regard to voice information transmission was apparently improved in all items than before improvement. Therefore, it is considering that these results would be utilized usefully when renovation on the hydraulic turbine dynamo room in the future.

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Design of Data Processing System for the Automatic Measurement of the Reverberation Time (잔향시간의 자동측정을 위한 데이터 처리 시스템 설계)

  • 이근구
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1984.12a
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    • pp.86-90
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    • 1984
  • In this paper, a method measuring the reverberation time simultaneously on all of the audio frequency range was studied. The system developed in this study is composed of a pink noise generator, filter bank, and microcomputer with graphic display. In the experiment, reverbration time data measured by existing analog method and by the system were compared, and were almost same through the audio frequency. Based on the conclusion, the subject method has more convenience and accuracy with algorithm program development without existing problems and it was found out that this kind of method is widely available for many branches of room accoustics and architectual acoustics.

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Acoustic Design of the Large Hall in Kimhae Performing Arts Center (김해 문화회관 대공연장의 음향설계)

  • 전진용;이호정;이병권;류종관
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.1070-1076
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    • 2001
  • In this study, the room acoustics of a hall in Kimhae Performing Arts Center is discussed. The hall is designed as a multi-purpose hall. The reverberation time of the hall is varied by absorptive/reflective surfaces. A design method using both objective and subjective evaluations is investigated. As a result, the geometrical shape and the interior materials are determined.

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Prediction of Room Acoustics Using Image Method (영상 음원법을 이용한 실내 음향 특성의 예측)

  • 이희원;이병호
    • The Journal of the Acoustical Society of Korea
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    • v.9 no.6
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    • pp.29-37
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    • 1990
  • 건축물이 갖게 될 음향학적 특성을 미리 예측함으로써 그 건축물의 음향학적 특성을 미리 예측 함으로써 그 건축물의 음향학적 요구에 맞는 설계를 수행할 수 있도록 하기 위해 computer simulation 방법을 개발하였다. 본 연구에서 사용된 simulation 방법은 영상음원법을 기초로 하였으며, simulation 에 의한 임펄스 응답이 유한한 시간 내로 제한되어 발생되어 오차를 줄이기 위한 방법이 제시되었다. 개발된 simulatio 방법으로 실내에서의 임펄스 응답, 잔향 곡선, early/rate energy ratio 등을 예측하고 실험 결과와 비교 하였으며, 실용적인 응용 가능성도 검토하였다.

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Noise Condition and Reduction Method for Diesel-locomotive Load Test Building (부하시험장 소음 실태 및 저감방안)

  • 조준호;이덕희;박준서;이규진
    • Proceedings of the KSR Conference
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    • 2002.10b
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    • pp.969-974
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    • 2002
  • Recently, many studies are performed according to increased interests about factory or room acoustics. In this study, the inside and environmental noise conditions of Diesel-locomotive load test building were investigated by multi-channel noise measurement system. In addition to this, the mitigation effects of environmental noise from this test building were analyzed using commercial software.

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Acoustic Properties of Three-room Coupled System by Connected Two Apertures (개구부로 연결된 3중 커플룸의 음향특성)

  • Na, Hae Joong;Lim, Byoung-Duk
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.3
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    • pp.340-349
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    • 2016
  • A coupled room system consists of adjacent rooms and apertures where the sound energy is exchanged between the two rooms. Acoustically, a coupled room system shows a non-exponential decay profile. Most of the related researches have been to analyze the acoustic properties of two-room coupled system so far whereas three-room coupled system were seldom studied. In this regard, this paper aims to analyse the distribution of sound pressure level, sound decay curve of three-room coupled system and sound energy flow between them by using the acoustic diffusion model and to further verify them through experiments. Firstly, the sound pressure level distribution and mean sound pressure level in the steady-state condition are analyzed at various frequencies and source locations. Good agreements are observed in both experiments and analysis results. Secondly, two double slope effect quantifiers of sound attenuation, LDT/EDT and LDT/T10 are compared at various frequencies and for different source locations. The result indicates that LDT/T10, less affected by the early reflection patterns than LDT/EDT, is more suitable to the analysis and experiments of a multi-slope sound decay curve. Lastly, the sound energy flow in each room is analyzed based on the acoustic diffusion model. After the early decay stage, the sound energy is observed to flow from the room with a long reverberation time to the room with a short one.

A Study on the Evaluation of Acoustic Performance for Music Room in Middle School using Auralization (가청화(可聽化)를 이용(利用)한 중학교(中學校) 음악실(音樂室)의 음향성능평가(音響性能評價)에 관(關)한 연구(硏究))

  • Soul, Soo-Hwan;Kang, Gyu-Sun;Kim, Jae-Soo
    • Proceeding of Spring/Autumn Annual Conference of KHA
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    • 2008.04a
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    • pp.272-275
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    • 2008
  • In case a middle school music room locating in Iksan City, this space had been finished its construction work with the indiscreet sound-absorbing materials despite the music lesson is taught thereat. Accordingly, when music lesson since it sounds aridly due to insufficiency of echo and sound-volume feeling in music appreciation or music performance sound, there is some difficulty in the music lesson. For the purpose to control the obstructive factors owing to such short Reverberation Time, it optimizes the acoustic factor using Acoustic Simulation after arrangement of Acoustic Design, it has conducted a Psycho-acoustics Experiment using the Auralizational Technique that can experience the Virtual Acoustic Field at its designing stage. As the result of investigation about the acoustic satisfaction on the relevant subject space and the satisfaction with regard to the pertinent each items, it was known that the valuation on acoustic performance was evidently improved at 'after-reformation' than 'before-reformation'. It is considered that such material could be utilized as the useful material that can improve the architectural acoustic factor when construction and renovation of any middle school music room in the future.

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