• Title/Summary/Keyword: Booming noise

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Booming Noise Reduction of Passenger Cars by Mode Decoupling of Structural-Acoustic Systems (구조-음향 모드 비연성에 의한 차량의 부밍 소음 저감)

  • 고강호;이장무
    • Journal of KSNVE
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    • v.9 no.4
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    • pp.822-827
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    • 1999
  • The reduction of booming noise level and improvement of sound quality in the vehicle interior have been major fields of vehicle NVH for many years. In order to reduce the booming noise this paper proposed a system variable, which takes account of mode shapes and natural frequencies of the structural-acoustic system, measurement points and excitation frequency. By simplifying the system variable, the major contributors of panels inculding roof, roof lining, wind shield glasses, doors and floor to booming noise at a specific frequency was experimentally found. Also the relationships between structural modes of roof lining, one of the major contributors, and acoustic modes of compartment cavity were investigated from the viewpoint fo structure-borne noise. In addition, the roof lining was modified structurally by applying marble sponge to the gap between roof and roof lining. Asthe result of structural modification, the booming noise was reduce at target frequency.

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Improvement of Interior Booming Noise in the Vehicle Using the Structural Dynamic Modification (구조물 동특성 변경을 이용한 실내 부밍 소음 개선)

  • Kim, Young-Ha;Lee, Jae-Woong;Kim, Sung-Gi
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.04a
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    • pp.354-359
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    • 2012
  • Improvement of structure-borne noises in the vehicle compartments has been one of the primary concerns in the development of vehicles. The booming is an annoying low frequency interior noise and vibration in vehicle. But it is difficult to reduce the structure-born booming noise in traditional method - trial and error within the shorten development schedule. So in present, the structure dynamic modification (SDM) method helpful to predict the effect of the local mass, stiffness, and damping is introduced. So in order to reduce the interior booming noise, the SDM was performed, and verified with modal test result. It was shown that the interior booming noise was reduced as predicted.

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Difference Limen for Just Noticeable Change of Booming Sensation in Frequency (차량 부밍소음의 청감 변화 인지를 위한 주파수 역치)

  • Shin, Sung-Hwan;Ih, Jeong-Guon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.621-624
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    • 2005
  • Among many auditory feelings for the vehicle interior noise, booming is considered as the most important nuisance to the passenger and developer. Because the main source of booming noise is a power train system including engine, in general, it consists of tonal components related to fundamental engine rotation and its harmonics including the firing frequency. Therefore, it is demanded to extract the effective tonal components only by using pitch extraction algorithm based on the place theory enable to find aurally relevant tonal components. However, there is a difference between booming sensation and pitch perception according to frequency change of tonal component. In this study, subjective listening test using a tracking method was performed to find the difference limen for just noticeable change of booming sensation in frequency. 20 Koreans and 10 Japanese were participated in this test and the results obtained from Koreans and Japanese were compared with each other. Finally, 5Hz was determined as the difference limen for just noticeable change of booming sensation in frequency, and by applying this value to booming analysis using pitch concept, it was confirmed that the degree of prediction of booming sensation was improved.

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STUDY ON THE OPTIMAL DESIGN OF A VEHICLE INTAKE SYSTEM USING THE BOOMING NOISE AND THE SOUND QUALITY EVALUATION INDEX

  • LEE J. K.;PARK Y. W.;CHAI J. B.
    • International Journal of Automotive Technology
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    • v.7 no.1
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    • pp.43-49
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    • 2006
  • In this paper, an index for the evaluation of a vehicle intake booming noise and intake sound quality were developed through a correlation analysis and a multiple factor regression analysis of objective measurement and subjective evaluation data. At first, an intake orifice noise was measured at the wide-open throttle test condition. And then, an acoustic transfer function between intake orifice noise and interior noise at the steady state condition was estimated. Simultaneously, subjective evaluation was carried out with a 10-scale score by 8 intake noise and vibration expert evaluators. Next, the correlation analysis between the psychoacoustic parameters derived from the measured data and the subjective evaluation was performed. The most critical factor was determined and the corresponding index for intake booming noise and sound quality are obtained from the multiple factor regression method. And, the optimal design of intake system was studied using the booming noise and the sound quality evaluation index for expectation performance of intake system. Conclusively, the optimal designing parameters of intake system from noise level and sound quality whose point of view were extracted by adapting comparative weighting between the booming noise and sound quality evaluation index, which optimized the process. These work could be represented guideline to system engineers, designers and test engineers about optimization procedure of system performance by considering both of noise level and sound quality.

BOOMING INDEX DEVELOPMENT IN A PASSENGER CAR (승용차 부우밍 인덱스 개발에 관한 연구)

  • Chae, Hee-Chang;Lee, Sang-Kwon;Park, Dong-Chul;Jung, Seung-Gyoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11a
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    • pp.332.2-332
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    • 2002
  • Booming sound is one of the most important interior sound of a passenger car. The conventional booming noise research was focused on the reduction of the A-weighted sound pressure level. However A-weighted sound pressure level can not give the whole story about the booming sound of a passenger car. In this paper, we employed sound metric which is the subjective parameter used in psychoacoustics. (omitted)

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Improvement of Sound Quality of Vehicle Through Reduction of Interior Noise Using Noise Transfer Path Analysis and Running Modal Analysis (소음 전달 결로 해석 및 주행 모두 해석을 이용한 차량의 실내소음 저감을 통한 음색 향상)

  • 이상권;황우석;김중희;우재학;이상희;이학준
    • Journal of KSNVE
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    • v.10 no.5
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    • pp.806-810
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    • 2000
  • This paper presents a practical method for reduction of interior noise and improvement of sound quality in compartment of passenger car. The tested vehicle has a booming noise problem at rear passenger seats. In order to identify the transfer path of interior noise, the running modal analysis, the vibro-acoustic frequency transfer response and the noise path analysis are systematically employed. Using these various methods, it has been founded that the rear part of the roof of the test car was a noise source for the booming noise. Through the modification of the roof, the booming noise has been reduced and sound quality inside car also has been improved.

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A Study on Transfer Characteristics of Vehicle Air-conditioner Booming noise (차량용 에어컨 부밍 소음의 전달 특성에 관한 연구)

  • Lim, Seung Taek;Joo, Kyung Hoon;Ahn, Hew Nam;Park, Young Duk;Kang, Yean Jun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.04a
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    • pp.476-481
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    • 2013
  • Transfer path analysis(TPA) and operational deflection shape(ODS) have been widely utilized to analyze the characteristics of noise. TPA enables to decompose a noise into air-borne and structure-borne noises then estimate the path contribution of noise. ODS enables to analyze a moving shape and direction of interest components at a particular frequency. In this paper, TPA and ODS are applied to transfer paths of air-conditioner booming noise in a vehicle to reduce noise level, then a fixture is mounted it's path for distributing the high portion path contribution to the low portion path contribution. Through this experiment, the reduction of sound pressure level in air-conditioner booming noise is observed. Thereafter, TPA is again employed to verify the results of contribution.

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Development of an Index for the Evaluation of Intake Booming Noise of a Passenger Car (차량의 흡기부밍소음 평가지수 개발)

  • Park Y. W.;Chai J. B.;Jang H. K.;Lee J. K.
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.9 s.90
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    • pp.884-890
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    • 2004
  • In this paper, an index for the evaluation of vehicle intake booming noise is developed through a correlation analysis of objective measurement data and subjective evaluation data. First, intake orifice noise is measured at the wide-open test condition. And then, acoustic transfer function between intake orifice noise and interior noise at the steady state condition is estimated. Simultaneously, subjective evaluation was carried out with a ten-scale score by 8 engineers. Next, the correlation analysis between the psycho-acoustic parameters derived from the measured data and the subjective evaluation is performed. The most critical factor was determined and the corresponding index for the intake booming noise is obtained from the multiple factor regression method. At last, the effectiveness of the proposed index is validated.

Booming Index Development in a Passenger Car (승용차 부우밍 인덱스 개발에 관한 연구)

  • Chae, Hee-Chang;Lee, Sang-Kwon;Park, Dong-Chul;Jung, Seung-Gyoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.273-278
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    • 2002
  • Booming sound is one of the most important interior sound of a passenger car. The conventional booming noise research was focused on the reduction of the A-weighted sound pressure level. However A-weighted sound pressure level can not give the whole story about the booming sound of a passenger car. In this paper, we employed sound metric which is the subjective parameter used in psycoacoustics. According to recent research results, the relation between sound metrics and subjective evaluation is very complex and has nonlinear characteristics. In order to estimate this nonlinear relationship, artificial neural network theory has been applied to derivation of sound quality index for booming sound of a passenger car.

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Booming Index Development of Interior Sound Quality on a Passenger Car Using Artificial Neural Network (신경망회로를 이용한 부밍음질의 인덱스 개발에 관한 연구)

  • 이상권;채희창;박동철;정승균
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.6
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    • pp.445-451
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    • 2003
  • Booming sound is one of the most important interior sound of a passenger car. The conventional booming noise research was focused on the reduction of the A-weighted sound pressure level. However A-weighted sound pressure level cannot give the whole story about the booming sound of a passenger car. In this paper, we employed sound metrics, which are the subjective parameters, used in psycoacoustics. According to recent research results. the relation between sound metrics and subjective evaluation is very complex and has nonlinear characteristics. In order to estimate this nonlinear relationship, artificial neural network theory has been applied to derivation of sound quality index for booming sound of a passenger car.