【分享】几篇应用raynoise被EI检索的文章

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Predicting speech metrics in a simulated classroom with varied sound absorption
  
Bistafa, S.R. (Department of Mechanical Engineering, Polytechnic School, University of Sao Paulo); Bradley, J.S. Source: Journal of the Acoustical Society of America, v 109, n 4, 2001, p 1474-1482
ISSN: 0001-4966 CODEN: JASMAN  
Publisher: American Institute of Physics Inc.  
  
Abstract: By systematically varying the amount of sound absorption, and the location of the sound-absorbing material in a simulated classroom, it was possible to assess the accuracy of the prediction of speech metrics in quite simple acoustical environments. Predictions of speech level, early-to-late sound ratios (C50) and speech transmission index (STI) values were obtained analytically and with two hybrid ray-based computer programs, RAYNOISE 3.0 and ODEON 4.1. The RAYNOISE predictions were accomplished with a purely specular reflection model and also with a calibrated diffuse reflection model. ODEON uses a parameter called transition order, TO, to change the reflection procedure from purely specular to diffuse for reflections that have orders higher than TO. A parametric study was conducted to determine the best transition order for the ODEON prediction of speech metrics. It was found that the analytical predictions of speech level and C50 were on average accurate to about 1 just-noticeable difference (jnd), whereas the analytical predictions of STI were on average within 2 jnd's. ODEON predictions of speech level, C50 and STI were on average within 2 jnd's. RAYNOISE predictions of C50 and STI with the specular model were on average within 2 jnd's. However, the RAYNOISE predictions of speech level, with both types of reflection models, and the RAYNOISE predictions of C50 and STI with the diffuse model had average errors greater than 2 jnd's. The effects of the sound-absorption treatments on the measured speech metric values are also discussed.

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Noise simulation sets the pace for design
  
Dawn, Tom Source: Noise and Vibration Worldwide, v 26, n 1, Jan, 1995, 5pp
ISSN: 0957-4565 CODEN: NVWOE6  
Publisher: Inst of Physics Publ Ltd  
  
Abstract: Computer modelling and simulation have enabled engineers to apply complex and repetitive calculations to their prime areas of interest. Sound simulation for instance indicates how a vehicle is likely to sound. The importance of such method is that it is a complete representation of the sound of the vehicle. Perhaps the most important example of simulation is a software-based engineering tool called sound quality tool introduced by SDRC. The sound quality tool is commonly used in conjunction with I-DEAS. A new development of the I-DEAS package in which Rayon is integrated is recently proposed. The package predicts how sound waves affect the structural performance of mechanical components and how vibrating structures generate noise. The most commonly used methods for acoustic and vibration modelling are together represented in a pair of well known software tools; Raynoise and Sysnoise. Both packages include on-line help, interactive viewing of the model and dynamic rotation of the model. Raynoise has an added feature which is a superset of the pull-down menu system called 'wizards'.

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Comparisons of computer simulations of acoustical conditions in classrooms
Bistafa, Sylvio R. (Natl Research Council); Bradley, John S. Source: Canadian Acoustics - Acoustique Canadienne, v 26, n 3, Sep, 1998, p 21-22
ISSN: 0711-6659 CODEN: CAACDX  
Publisher: Can Acoust Assoc  
  
Abstract: Two computer programs were used to compare the computer simulations of acoustical conditions in classrooms. Odeon 2.6 and Raynoise 2.1 A use hybrid models in that they combine different procedures for calculating the earlier and later parts of the impulse response. The classroom had dimensions of 7.6 m×10 m and 3.3 m height. Four different sound absorption material configurations, using mineral wool, were simulated to study the relation between reverberation and speech intelligibility. The simulations showed that the speech intelligibility metrics have been consistently estimated using two different room acoustic programs. The prediction of reverberation time deviate from expected values at high frequencies for a very reverberant room

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Validation of ray acoustics applied for the modelling of noise barriers
van Haaren, E. (NS Technisch Onderzoek); van Tol, P.H. Source: Journal of Sound and Vibration, v 231, n 3, Mar, 2000, p 681-688
ISSN: 0022-460X CODEN: JSVIAG  
Conference: 6th International Workshop on Railway Noise-Foreword, Nov 4-Nov 6 1998, Island of Les Embiez, France  
Publisher: Academic Press  
  
Abstract: Ray acoustics have been used to investigate the effectiveness of noise barriers in railway applications. Various types and shapes of barriers are modelled using the commercial software RAYNOISE. Absorbing and reflecting configurations as well as barriers at different angles are included. The numerical results are validated by measurement of the insertion loss for four types of barriers. A-weighted sound pressure levels have been calculated at six locations, 25 m from the track and are compared with the experimental values. The source strengths were selected to represent a high-speed train. The measurements were carried out using a microphone array; therefore the tests could be carried out alongside noise barriers of reduced length. The barrier measurements have already been validated against train pass-by measurements and have shown to be accurate within 1-2 dB (A). Insertion losses up to 15 dB (A) have been measured and calculated. Comparison between numerical and experimental values show agreement within 2 dB (A). The sensitivity of the numerical models to some numerical parameters as well as to the barrier-to-track distance was investigated. The results show that there is significant dependence on parameters, such as the number of rays and the order of reflection. Therefore, some guidelines are proposed in order to achieve stable results. In a single case of a reflecting barrier, the barrier-to-track spacing is quite critical, due to a reflection effect. The main conclusion is that ray acoustics can be a powerful tool in investigating the effectiveness of noise barriers, and that the accuracy of the calculated A-weighted sound pressure levels is within acceptable limits. (2 refs.) (Author abstract)

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On the accuracy of the assessment of room acoustics parameters using MLS technique and numerical simulation
Gomes, M.H.A. (Federal Univ of Santa Catarina); Gerges, S.N.Y.; Tenenbaum, R.A. Source: Acta Acustica (Stuttgart), v 86, n 5, Sep, 2000, p 891-895
ISSN: 0001-7884 CODEN: AAACFD  
Publisher: S. Hirzel Verlag GmbH  
  
Abstract: Advances in psychoacoustics through the years, have made it possible to evaluate the acoustical quality of a room, based on several numerical parameters that have been developed. Even though there is not a total agreement about which parameters are truly important, some of them are accepted by most of the acousticians. When designing a concert hall, ray-tracing softwares can be used to calculate some of these parameters. However, some input data carry some uncertainties. Available data for absorption coefficients have to be used carefully and, beyond that, there is not a standardized recommendation for measuring diffusion coefficients, nor a data base for this parameter. This paper presents a comparison of a room simulated with one of the commercial softwares available (RAYNOISE), and the measured parameters in this same room, using Maximum Length Sequence (MLS). Discrepancies over the results are investigated and analyzed. (15 refs.) (Author abstract)