• Title/Summary/Keyword: Noise control

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Vector Base Amplitude Panning Based Noise Control Method for Improving the Amenity in Building Environment (실내 환경에서 쾌적성 향상을 위한 Vector Base Amplitude Panning 기반의 소음제어)

  • Kwon, Byoung-Ho;Park, Young-Jin;Park, Youn-Sik
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.6
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    • pp.521-528
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    • 2011
  • A variety of noise control methods have been developed as an interest on noise issues increases. Among them, noise control methods using masking effect, a phenomenon to reduce the ability to notice the unwanted sound by proper sound, to implement a pleasant sound environment have been studied under the name of soundscape. We proposed a novel vector base amplitude panning(VBAP) based noise control method to apply to the building environment. The proposed method could improve the amenity inside the building to reproduce the sounds with excellent masking effect on the incoming path of noise using the control speakers, considering the direction of noise source. The directional masking sounds can be generated by using VBPA technique. To verify the performance of the proposed method, we carried out the subjective test for the degree of amenity according to direction of the masking sound. Subjective test results showed that it is possible to improve the amenity inside the building by controlling the direction of masking sound considering the human's auditory characteristic.

Vibration and Noise Control of Structural Systems Using Squeeze Mode ER Mounts

  • Jeong, Weui-Bong;Yoo, Wan-Suk;Jung, Woo-Jin
    • Journal of Mechanical Science and Technology
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    • v.17 no.12
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    • pp.1949-1960
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    • 2003
  • This paper presents vibration and noise control of flexible structures using squeeze mode electro-rheological mounts. After verifying that the damping force of the ER mount can be controlled by the intensity of the electric fild, two different types of ER squeeze mounts have been devised. Firstly, a small size ER mount to support 3 kg is manufactured and applied to the frame structure to control the vibration. An optimal controller which consists of the velocity and the transmitted force feedback signals is designed and implemented to attenuate both the vibration and the transmitted forces. Secondly, a large size of ER mount to support 200 kg is devised and applied to the shell structure to reduce the radiated noise. Dynamic modeling and controller design are undertaken in order to evaluate noise control performance as well as isolation performance of the transmitted force. The radiated noise from the cylindrical shell is calculated by SYSNOISE using forces which are transmitted to the cylindrical shell through two-stage mounting system.

The Study on the Performance Improvement and the Development of Active Intake Noise Control System (능동홉기소음제어 시스템의 개발 및 성능향상에 관한 연구)

  • 이충휘;오재응;심현진;이유엽
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.326-329
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    • 2002
  • Engine noise is one of the major causes of the interior noise, and so has been studied in various ways in recent days. Recently Intake noise has been extensively studied to reduce the engine noise. Conventional method to reduce the noise is adding several resonators to the induction system. However this causes a reduction of engine output power and an increase of fuel consumption. In this study, the prototype of Active Intake Noise Control System is developed by using the Filtered-x LMS algorithm to reduce the Intake noise during acceleration. Intake noise is more excessively increased when the engine is rapidly accelerated. So, Normalized LMS algorithm is applied to improve the control performance under the rapid acceleration.

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Noise Control of an Air Intake system for a Four-Cylinder Engine (4기통 엔진의 흡기계 소음제어)

  • 김태정;홍상범
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1996.10a
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    • pp.77-83
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    • 1996
  • Noise control process of an air intake system for a four-cylinder automotive engine is described. The objective of the process is reduction of induction noise without losing engine performance and changing package layout. The theory and feasibility for noise control elements are also discussed. In general, four-cylinder engines generate a lower frequency induction noise around 80-150 Hz (2400-4500 rpm) and firing frequency, valve impact noise are the main sources. In this paper, the most problematic noise source is identified first and better position of air inlet is selected between inside-fender and out-of-fender layouts. Secondly, the possible noise control approach and CAE analysis results are compared to those from speaker excitation tests. Finally, the effect of the controlled intake system after the installation to an automobile is presented.

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Vibration and Noise Control of the Simply Supported Slab Using the Multi-tuned Mass Damper (다중동조질량감쇠기를 이용한 단순지지 슬래브의 진동 및 소음저감에 관한 연구)

  • Hwang, Jae-Seung;Hong, Geon-Ho;Park, Hong-Gun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.10
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    • pp.1006-1013
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    • 2008
  • In this study, it is outlined that heavy weight floor impact noise induced by the vibration of slab can be reduced using multi tuned mass damper(MTMD) effectively. Substructure synthesis is utilized to develope analytical model of the slab coupled with MTMD and acoustic power is introduced to evaluate the performance of noise control for simplicity. Numerical analysis is carried out to investigate the effect of the properties of MTMD on the vibration and noise control of the simply supported slab. Numerical analysis shows that mass ratio of MTMD is critical on the vibration and noise control of the slab and it is also essential to reduce the vibration in higher modes of slab in the light of its great effect on the radiation of sound.

Active Noise Control of Closed Rectangular Cavity using the FXLMS Algorithms (FXLMS 알고리듬을 이용한 사각밀폐공간의 능동소음제어)

  • Ryu, Kyung-Wan;Hong, Chin-Suk;Jeong, Wei-Bong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.04a
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    • pp.247-249
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    • 2009
  • This paper investigates active noise control(ANC) of a rectangular cavity using single channel filtered-x least mean square(FXLMS) algorithms to reduce interior noise globally. To obtain global reduction of the interior noise, multichannel active control should be incorporated in general. We, however, examined firstly the optimal location of the secondary speaker that produces a global reduction of the interior noise field. We then investigated the frequency characteristics of the reduction to yield the effective frequency band of the active control system. It follows that the secondary speaker should be located as close to the primary source as possible in order to obtain global reduction.

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Vibration and noise control of slab using the multi-tuned mass damper (다중질량감쇠기를 이용한 슬래브의 진동 및 소음저감에 관한 연구)

  • Hwang, Jae-Seung;Kim, Hong-Jin;Kang, Kyung-Soo;Hong, Gun-Ho
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.04a
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    • pp.659-664
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    • 2008
  • In this study, it is outlined that heavy weight floor impact noise induced by the vibration of slab can be reduced by multi tuned mass damper(MTMD) effectively. Substructure synthesis is utilized to develope analytical model of slab coupled with MTMD and acoustic power is introduced to evaluate the performance of noise control for simplicity. Numerical analysis is carried out to investigate the effect of the properties of MTMD on the vibration and noise control. Numerical analysis shows that mass ratio of MTMD is critical on the vibration and noise control of the slab and it is essential to reduce the vibration in higher modes of slab because it has a great effect on the radiation of sound.

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Active Control of Road-Booming-Noise with Constraint Multiple Filtered-X LMS Algorithm

  • Oh, Shi-Hwan;Kim, Hyoun-Suk;Park, Young-Jin
    • The Journal of the Acoustical Society of Korea
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    • v.19 no.2E
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    • pp.3-7
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    • 2000
  • Vibration generated by the non-uniform road profile propagates though each tire and the suspension and finally generates structure born noise in the interior of the passenger vehicle. In this paper, the road-booming-noise which has strong correlation with the vibration signals measured at the suspension system was compensated. Active noise control of the road-booming-noise is rather difficult to achieve because of its non-stationary characteristics. CMFX LMS (Constraint Multiple Filtered-X Least Mean Square) algorithm, which can track non-stationary process rather well, is applied. Comprison of the proposed method and the conventional MFX LMS (Multiple Filtered-X Least Mean Square) algorithm is made through the hardware-in-the-loop simulation and the feasibility of the proposed method is demonstrated with the experiment.

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Active Noise Control in a Circular Duct Using Smart Foam (원형 덕트 내에서 스마트 폼을 이용한 능동 소음 제어)

  • Han, Je-Heon;Kim, Pyo-Jae;Kang, Yeon-June
    • Proceedings of the KSME Conference
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    • 2001.06b
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    • pp.641-645
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    • 2001
  • In this paper, it is discussed that active noise control in a circular duct using smart foam. Firstly, it is demonstrated that the potential of the conventional smart foam, proposed by Fuller, for active noise control in a duct. Conventional smart foam is not applicable to active noise control in a duct having flow. Thus, this paper presents a ring-type smart foam as an alternative. The ring-type smart foam consists of polyurethane acoustic foam of lining shape and PVDF film embedded in the foam. The embedded PVDF element acts as an actuator to reduce noise at lower frequencies and the foam absorbs noise at higher frequencies. A filtered-x LMS controller is used to minimize the signal from the error microphone. Experiments are executed to reduce broadband and tonal noise.

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Experimental Study for Construction Equipment's Cabin Noise Control (건설장비 캐빈 저소음화를 위한 시험적 연구)

  • Lee, Tae-Kyoung;Joo, Won-Ho;Bae, Jong-Gug
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.8
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    • pp.802-808
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    • 2009
  • In this paper, the experimental study on the identification of noise sources and noise transmission paths was carried out for the cabin noise control of construction equipment. In order to investigate noise and vibration characteristics of cabin structure, sound absorption, transmission, and radiation tests were performed using cabin assembly models. The noise/vibration source levels were obtained from the real cabins of wheel loader and excavator. Using transfer functions of cabins and real cabins' source data, cabin noise was decomposed into airborne and structureborne noise transmissions. Finally noise sources and major transmission paths were successfully identified for wheel loader and excavator's cabins.