Noise Control Engineering Journal (NOISE CONTROL ENG J)
Noise Control Engineering Journal is the technical publication of the Institute of Noise Control Engineering. NCEJ is issued bimonthly, and contains technical articles on all aspects of noise control engineering.
Journal Impact: 0.56*
Journal impact history
|2016 Journal impact||Available summer 2017|
|2015 Journal impact||0.56|
|2014 Journal impact||0.58|
|2013 Journal impact||0.96|
|2012 Journal impact||0.90|
|2011 Journal impact||0.80|
|2010 Journal impact||0.51|
|2009 Journal impact||0.46|
|2008 Journal impact||0.40|
|2007 Journal impact||0.55|
|2006 Journal impact||0.39|
|2005 Journal impact||0.28|
|2004 Journal impact||0.32|
|2003 Journal impact||0.45|
|2002 Journal impact||0.32|
|2001 Journal impact||0.14|
|2000 Journal impact||0.18|
Journal impact over time
|Website||Noise Control Engineering Journal (NCEJ) website|
|Other titles||Noise control engineering journal|
|Document type||Journal / Magazine / Newspaper|
Publications in this journal
- [Show abstract] [Hide abstract] ABSTRACT: This paper considers a piezoelectric transducer polarized in the thickness direction and laminated with a piezoelectric disk. Its vibration characteristics were investigated theoretically and experimentally in the scope of the radial and axial motions in axisymmetric vibration modes. Theoretically, the differential equations of piezoelectric motions were derived in terms of radial and axial displacements and electric potential, and they were solved to produce characteristic equations that provided natural frequencies and mode shapes. Experimentally, the natural frequencies were measured using an impedance analyzer and the radial in-plane motions of the fundamental mode were measured using an in-plane laser interferometer. The results of the theoretical analysis were compared with those of a finite-element analysis and experiments, and the theoretical analysis was verified on the basis of this comparison. It appeared that the natural frequencies of the radial modes of the piezoelectric transducer were not affected by the added piezoelectric disk; however, those of the thickness modes were reduced by the piezoelectric disk owing to the added mass effect.
- [Show abstract] [Hide abstract] ABSTRACT: A numerical model is applied to study the application and performance of active structural acoustic control (ASAC) in automotive cabins. The vibro-acoustic problem is composed of a rectangular acoustic cavity, representing vehicle compartment, coupled with a free-free panel, representing the windshield, and a simply supported panel, representing the floor panel. In the formulation of ASAC, noise transfer functions are used to calculate the control forces based on their ability to minimize the total acoustic potential energy in a specific region of interest inside the cabin. Results show that when ASAC is applied at the same panel radiating the primary noise, a significant reduction in the total acoustic potential energy in the region of interest is achieved. It was also observed that the performance of ASAC improves more as the number of control forces is increased. However, when ASAC is applied at a panel different than the primary noise radiating panel, ASAC becomes ineffective. Moreover, results indicate that, in this case, increasing the number of control force, does not improve the total acoustic potential energy reduction in the region of interest. It is found that the main reason behind the ineffectiveness of ASAC is the difference in the vibro-acoustic characteristics of the source and control panels as well as the modal coupling between the control panel and cavity modes. This leads to significant modal participations of higher cavity modes in the low frequency response and thus makes ASAC inefficient.
- [Show abstract] [Hide abstract] ABSTRACT: The paper analyzes the long-term noise monitoring data using autoregressive integrated moving averages (ARIMA) modeling technique and artificial neural networks (ANNs) methodology. Box-Jenkins ARIMA and ANN approach have been utilized to simulate daily equivalent LDay (06-22h) and LNight (22-06h) in A and C weightings for a period of 1 year. The forecasting performance is ascertained using the statistical tests. The work draws a comparison of time-series ARIMA and ANN approach for ascertaining their suitability for traffic noise modeling and forecasting. It is observed that the artificial neural network (ANN) models outperform the ARIMA models so developed. The pattern of ARIMAf orecasting models is directional and as such the time-series predictive model utilizing ANN approach has demonstrated superior performance over the ARIMA model.
- [Show abstract] [Hide abstract] ABSTRACT: The aim of this study was to develop a sound quality index for assessing the sound of window lift modules during operation. Window lift operations were classified as “ascent” and “descent,” and sound quality indices were developed for each operation and compared. A subjective test was performed by using six models and 12 samples based on a semantic differential method in which 76 jurors participated. In order to quantify the subjective sound quality preferences, correlations between factors were determined through factor analysis. The sound quality preferences from the subjective test were analyzed through regression analysis. For ascent, the relevant factors were determined to be described by luxuriousness and uniformity. For descent, the relevant factors were explained by luxuriousness and strength. Reliable equations that relate each of these factors with high preference were developed for both operations. A sound quality index was developed through regression analysis between the factors. Correlations between each factor and previously developed sound quality metrics were also analyzed to finally derive an equation that explains the preference in terms of sound quality metrics.
- [Show abstract] [Hide abstract] ABSTRACT: As part of the Sound-Structure Interaction course, offered through the Penn State Graduate Program in Acoustics, a set of demonstrations was developed to help reinforce structural acoustics theory. A common test article, a simply supported plate, was developed for a set of four demonstrations. The simply supported plate was used to demonstrate the concepts of mobility functions, radiated sound directivity, fluid loading and acoustic transmission loss. A modal impact hammer, accelerometers, microphones, a sound level meter and a sound intensity probe were used in combination with National Instruments compact DAQ systems and LabVIEW software to develop these custom demonstrations. Basic theory and setup of the demonstrations are presented as well as links to the videos of the demonstrations themselves.
- [Show abstract] [Hide abstract] ABSTRACT: A series of experiments was conducted in the present study in an attempt to understand how the implementation of active noise control would affect the sound transmission across a plenum window. A simple squared pressure control scheme with three error sensors equi-spaced on the vertical centerline of the indoor window opening was adopted. The secondary control loudspeakers were fixed close to the outdoor window opening. The effects of secondary control loudspeaker orientation relative to the plenum cavity and their locations on the performance of the active control were investigated. Results show that the active control system with two loudspeakers located symmetrically about the plenum cavity horizontal centerline facing directly the incoming noise gives the best performance. However, the effective frequency range is restricted to that below the first asymmetric mode cut-off frequency in the window gap direction. The active control performance is improved when the reverberation strength of the receiver chamber is reduced in general.
- [Show abstract] [Hide abstract] ABSTRACT: The filtered-x least mean square algorithm (FxLMS) is a widely used technique in active noise control. In a conventional FxLMS algorithm, the value of convergence coefficient is kept constant which may not yield optimum performance if frequency of the primary noise changes. For some frequencies, this may result into a slower convergence and for some other frequencies, it may lead to instability. To deal with this situation, a normalized FxLMS algorithm, in which the convergence coefficient is normalized with the power of the filtered reference signal, is proposed. In the eigenvalue equalization method, the magnitude of secondary path transfer function is equalized such that the power of filtered reference signal remains equal at all the frequencies. The method proposed in this paper attempts to optimally adapt the convergence coefficient of the FxLMS algorithm for continuously varying noise. It is based on estimating how frequency of noise is varying using fast Fourier transforms of the reference signal and then, using this information to optimally adapt the convergence coefficient. The optimum value of the convergence coefficient is decided based upon the power and delay of the filtered reference signal and sampling frequency. A numerical study in a 3D acoustic cavity is presented to test the effectiveness of the proposed method and the results are also compared with the conventional FxLMS and the frequency-domain FxLMS algorithm. It is found that the proposed method leads to a faster convergence which results in higher noise reduction especially when the frequency of noise varies continuously. Simulation results show that the noise reduction obtained depends upon the rate at which the frequency of the primary noise varies. The higher the rate of variation and the duration for which the variation exist, the better the performance of the proposed method is over the conventional FxLMS algorithm in terms of noise reduction. The frequency-domain FxLMS algorithm is not found to be effective if the frequency of primary noise varies continuously.
- [Show abstract] [Hide abstract] ABSTRACT: The noise radiated by electronic devices often results from the axial fans used to cool them. One component of axial fan noise is created by fluid shearing in the tip clearance region. In aero engines and other turbine applications, tip noise can be reduced by installing a finite flow resistance strip in the housing around the fan circumference. The finite level of flow resistance created by the slightly permeable housing may dissipate small-scale fluid motions, which may in turn reduce turbulence levels in the tip region and so reduce the tip noise. In the present work, the housing of a 120 mm axial fan was modified to accommodate strips of finite flow resistance, microperforated materials. The fan performance with and without the microperforated treatment was measured so that modified and unmodified fans could be operated at the same performance points and acoustical testing was performed using the ISO 10302 plenum. The fan noise was quantified on the basis of the blade passage tone level and tests were performed using microperforated materials spanning a range of flow resistances. It has been found that there are areas in the fan performance map where tonal noise levels can be consistently reduced by the use of a microperforated housing element.
- [Show abstract] [Hide abstract] ABSTRACT: The objective in this study was to develop a compact, multi-chamber silencer incorporating dissipative microperforated elements that could be used to reduce transmitted noise in a flow system. Two expansion mufflers in series were used to create a relatively compact system that attenuated sound effectively over the speech interference range. The microperforated elements were used both to improve the acoustic performance of the silencer and to reduce the system pressure drop with respect to a muffler without a microperforated lining. Both finite element modeling (FEM) simulation and experimental methods were employed in the detailed design of the multi-chamber silencer. In the FEM simulations, the microperforated lining was modeled as a fluid layer having complex properties, and the model was used, for example, to identify the optimal location of the microperforated lining. The predicted results were successfully compared with full-scale experimental results that were obtained by using a four-microphone standing wave tube.
- [Show abstract] [Hide abstract] ABSTRACT: The A-weighted equivalent sound level, LAeqT, is commonly used for road traffic noise assessment, where the time interval T equals a few minutes, hours, days, evenings or nights. Fluctuations in traffic flow, vehicle speed and vehicle generation parameter account for differences between measured values of LAeqT. It is shown that the standard deviation of LAeqT depends not only on variations of these parameters, but also on the flow distribution along road lanes. The proposed method enables calculation of the standard deviation when a road consists of a few lanes and when the statistical characteristics of all parameters are known.
- [Show abstract] [Hide abstract] ABSTRACT: Environmental sound levels represent the cumulative contributions of many types - and possibly an uncountable number - of sound sources. This recommends a statistical approach to modeling. Using 1.5 million hours of acoustical data from hundreds of sites, regression models were built to predict sound levels across the contiguous United States. These models discern often nonlinear and interacting relationships between measured sound levels and nonacoustic environmental summaries extracted from nationwide geospatial data layers. Tens of potential explanatory factors were examined including climate, topography, human activity, and time of day and year. Mapping sound levels at landscape scales and diagnostic tools, like partial dependence functions, can reveal the effects of influential factors on measured sound levels. These results illustrate the foundations of many spatiotemporal patterns, provide tools for understanding current acoustical conditions and demonstrate the potential consequences of shifts in environmental conditions.
- [Show abstract] [Hide abstract] ABSTRACT: Viscoelastic oscillator (VEO) is the basic model extracted from viscoelastic damping structures. To precisely understand the dynamic behavior of VEO, generalized modeling of fractional viscoelastic oscillator (FVEO) is proposed and its frequency response is deduced. For demonstrating purpose, frequency response of three FVEOs is studied. As an engineering application case, the viscoelastic suspension mounted in a heavy crawler-type vehicle is considered and its vibration model is built by FVEO, whose time-domain solution is numerically derived by matrix differential theory. The results indicate that FVEO is a valid approach to evaluate the dynamic response of viscoelastic damping structures.
- [Show abstract] [Hide abstract] ABSTRACT: This paper presents a small-typed active noise barrier (ANB) with sound masking techniques for alleviating the noise problem and protecting the speech privacy in open-plan offices. This soundproof system reduces and masks the undesired sound simultaneously so that lower level of the masker is required to achieve the sound masking effect, comparing with the conventional sound masking systems. First, a real-time experiment to verify the noise attenuation performance of the proposed system for practical application has been conducted in a real office room. In the experiment, the influence of background noise on the system performance has also been investigated. The experiment results show that 3-8 dB active noise attenuation can be achieved behind the ANB in an office room. Moreover, in order to select an appropriate masker for the sound masking part of the system, several maskers have been compared and investigated by listening experiments. The results suggest that the stationary maskers are more suitable for the sound masking in offices by considering the sound masking performance and the annoyance of the maskers comprehensively.
- [Show abstract] [Hide abstract] ABSTRACT: Approaches to outdoor sound propagation include models of attenuation for a set of standardized barriers and terrains. These various approaches take care to represent the physical nature of each barrier type. However selection of the appropriate barrier model for a real-world terrain segment is rarely presented. Complex logic is required to determine the appropriate barrier model to apply in the instances where the selection is addressed. This paper presents the Critical Point Analysis Terrain Simplification (CPATS), an algorithm for reducing the complexity of real-world terrain profiles. CPATS implements a finite differencing schema to determine critical points within the terrain segment. The results of this model are compared to a maximum deviation algorithm (MaxDev) of reducing terrain complexity. A statistical comparison between CPATS and MaxDev terrains is completed showing the superior capabilities of the CPATS model. The effect of the different simplified terrains is examined using the outdoor sound propagation code NORD2000.
- [Show abstract] [Hide abstract] ABSTRACT: Numerous previous studies have been conducted on quantifying road noise through transfer path analysis (TPA) using the matrix inversion and the dynamic stiffness methods. However, the matrix inversion method is a calculation that always contains error, even when treated with the best condition number found by trial and error iteration to match the calculation SPL (sound pressure level) to measured SPL. Furthermore, the caveat of the dynamic stiffness method is that it requires accurate dynamic stiffness value up to the frequency range of interest, which, in reality, is rarely available and is challenging to obtain. Therefore, TPA using these two methods is only possible when a complete vehicle is available. For the sake of cost and time reduction, circumventing these limitations is crucial within the vehicle production period. The main focus of the present study is to directly obtain the operational forces at the suspension mounting points neglecting the effect of the vehicle body through a special suspension rig. The suspension rig is verified through a comparative analysis with the actual baseline vehicle measurement up to 250 Hz. In addition, an example approach for finding suspension's NVH performance improving factor using the rig benchmarking technique is introduced.
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