体育馆声学设计探讨

本文分析了我国综合性体育馆共同的体形特征及其所导致的运用建筑声学时的出现的若干问题,探讨了有关的声学标准,并以工程实践为例,说明必须依靠建筑声学设计和电声设计的结合,才能作好体育馆的声学设计。     

体育馆声学设计探讨

本文分析了我国综合性体育馆共同的体形特征及其所导致的运用建筑本学时出现的若干问题，探讨了有关的声学标准，并以工程实践为例，说明必须依靠建筑产学设计和电声设计的结合，才能作好体育馆的声学设计．     

国家奥林匹克体育中心综合体育馆和游泳馆的声学设计

国家奥林匹克体育中心包括综合体育馆、游泳馆、两个练习馆和体育场等五项工程.本文着重介绍体育中心两个主馆的声学设计、竣工后的调试和取得的成果,以及笔者对今后大型体育馆声学设计的建议.     

上海市黄浦体育馆的声学设计

上海市黄浦体育馆建于1981年9月,是一座多用途大厅,除供体育比赛外,还兼作集会及音乐演出之用.容座总共3800个.大厅平顶采用十字形空间吸声体处理,式样美观新颖,效果良好而经济.中频(500—1000Hz)满场混响时间约1.3s.扩声系统采用分区式声柱布置方案.使用效果表明音质符合设计要求.     

广东星海音乐厅室内乐厅的声学设计

室内乐厅是以演奏室内乐为主、兼供独奏(唱)、音乐讲座、文娱演出和立体电影所用的多功能厅堂。为使各项功能均具有最佳的声学条件,设置了用计算机调控混响时间的装置。本文概要介绍室内乐厅的声学设计、但侧重于计算机调控混响时间所取得的成效。     

大连广电中心广播电视剧场声学设计

广播电视剧场是随着电视技术的发展和需要而产生的一种新的观演建筑的形式,它不同于一般的演播室,也有别于普通的剧场。它不仅要求能够进行电视节目的转播和录制,还要求能够进行音乐、歌舞等各种文艺节目的演出,并能够举行会议和放映立体声电影,因此,广播电视剧场对音质有很高的要求。本文介绍了大连广播电视中心广播电视剧场的建声设计,在该剧场内采用了计算机控制的可调混响装置,使得各种使用功能都能有一个较为理想的建声环境。     

保利剧院的声学设计

保利剧院是一座继承传统歌剧院的良好品质,又能适应近代各种需求的专业歌剧院,兼供自然声音乐演奏和戏剧演出,为确保剧有良好的音质,从方案阶段就开始声学设计,并贯穿于设计、施工、试用调试的全过程,从而获得了良好的音质,评价颇高,本文概要介绍保利剧院的声学设计及从中取得的经验。     

北京剧院的声学设计

北京剧院是一个以戏剧演出为主的多功能剧院,容纳1000名听众。为在声学上适应多种剧目演出的要求,在观众厅内设置了可调吸声结构;为满足自然声音乐演出的需要,着重考虑了厅内的声扩散设计,并在舞台上配置了活动音乐罩和升降乐池。本文主要介绍该剧场的声学设计和所取得的成果,以此证实了在声学上实现多功能使用的必要性和可能性。     

儿童球幕电影厅的声学设计

圆形平面或穹形平顶存在着明显的声学缺陷,这种现象在半球形房间中尤为严重。一座具有这种形状的球幕电影厅的声学设计是在钢筋混凝土薄壳完成以后才提出来的,所以增加了工作难度。因此必需采用一些特殊声学处理,要求重量轻、吸声强、具有散射特性等以减少圆墙和圆顶的聚焦和爬行效应,同时还要控制大厅的混响时间。经过多种声学措施后,达到了满意的室内音质效果。     

Evaluation of the acoustic performance of classrooms in public schools

This paper presents the results of an evaluation of acoustic comfort of classrooms built according to a standard design. Three constructive designs located in the metropolitan area of Curitiba (Brazil) have been evaluated, two schools built under each of these three designs, in a total of six schools. The acoustic quality of the classrooms have been analyzed based on measurements of the reverberation time, sound pressure level inside and outside the classrooms, and sound insulation. Measurements of ambient noise (external and internal) followed the Brazilian Standards NBR 10151 and NBR 10152. Measurement of reverberation time and sound insulation followed the international Standards ISO 140-4, ISO 140-5, ISO 717-1, and ISO 3382. Results (sound insulation and reverberation time) have been compared with reference values found in the Brazilian Standard NBR 1279, and in the Standards ANSI S12.60 and DIN 18041. Results reveal poor acoustical quality of the surveyed classrooms, for all 3 constructive designs studied. The surveyed designs do not meet the guidelines of either the Brazilian Standards or of the International Standards employed as references.     

Objective and subjective evaluation of acoustic comfort in classrooms: A comparative investigation of vernacular and modern school classroom in Kerala

This paper reports a comparative investigation on acoustic comfort of classrooms in vernacular and modern school buildings in tropical warm humid climate. In this type of climate the intrusion of external noise into the classrooms along with cross ventilation is unavoidable. Preliminary investigation on the evaluation of acoustic comfort carried in secondary schools located in Kollam district of Kerala State in India have been reported. As a step ahead, in order to understand the performance of vernacular school classroom in comparison with that of a modern classroom, an initial survey was conducted in classrooms of ten vernacular and 10 modern schools. Further a detail investigation was carried out in a vernacular and modern school building located in the same site. The study was conducted by measuring the two important acoustic parameters viz., background noise and reverberation time which affect the acoustical comfort in the classrooms. The level of satisfaction of the users was evaluated through questionnaires distributed to teachers and students. The result of the scientific analysis was compared to user’s response. The study reveals that modern classrooms are more preferred than vernacular classrooms acoustically, by the teachers and students. The study also confirms a strong need of improving the acoustical comforts in the classrooms.     

Acoustical design and experimental verification of school music rooms: A case study

This paper presents an approach to acoustical design and the results of a survey in music rooms in an Italian public school (Liceo Statale “Alfano I” in Salerno, Italy). The locations selected are devoted to orchestral performances and to recording.     

Numerical treatment of acoustic problems with the smoothed finite element method

We incorporated a cell-wise acoustic pressure gradient smoothing operation into the standard compatible finite element method and extended the smoothed finite element method (SFEM) for 2D acoustic problems. This enhancement was especially useful for dealing with the problem of an arbitrary shape with violent distortion elements. In this method, the domain integrals that involve shape function gradients can be converted into boundary integrals that involve only shape functions. Restrictions on the shape elements can be removed, and the problem domain can be discretized in more flexible ways. Numerical results showed that the proposed method achieved more accurate results and higher convergence rates than the corresponding finite element methods, even for violently distorted meshes. The most promising feature of SFEM is its insensitivity to mesh distortion. The superiority of the method is remarkable, especially when solving problems that have high wave numbers. Hence, SFEM can be beneficially applied in solving two-dimensional acoustic problems with severely distorted elements, which, in practice, have more foreground than regularity mesh.     

A study on the applications of the acoustic design sensitivity analysis of vibrating bodies

The determination of the sensitivity of the acoustical characteristics of vibrating systems with respect to the variation of the design parameters predicting these characteristics is a necessary and important step of the acoustic design and optimization process. Acoustic design sensitivity analysis includes the computation and evaluation of the sensitivity information required for this procedure. In this study, a boundary element code performing the sensitivity analysis of the acoustic pressure by using the matrix sensitivities with respect to different design variables has been developed. The effect of the precision of boundary element discretization on the acoustic pressure sensitivity is examined via this code. The formulation is applied to a multi-source system and the dimension sensitivity analysis of near field pressures of two-dilating-spherical source is performed. The last application is devoted to a real sound source: a washing machine sitting on the floor. Sensitivity of the field pressures to the machine’s dimensions (size), surface velocity and frequency is examined on the bases of the boundary element model of the machine and half-space condition. The impacts of these variables are compared; and a limiting speed for the machine responding both the acoustical and operational requirements is determined.     

Influence of wall absorption on low-frequency dependence of reverberation time in room of irregular shape

In this paper, a modal analysis was used to describe a reverberation phenomenon in a room of complex shape. A theoretical model was limited to low sound frequencies, when eigenmodes are lightly damped, thus they may be approximated by uncoupled normal acoustic modes of a hard-walled room. A utility of this method was demonstrated in a numerical example where the enclosure in a form of two coupled rooms was considered. A reverberation time was evaluated from a time decay of spatial root mean square pressure, the overall measure of room pressure. The results of calculations, performed for three different distributions of absorbing materials on room walls, showed how various location of the material can effect a dependence of the reverberation time on a frequency of sound source.     

Optimal design of acoustic performance for automotive air-cleaner

The research on optimal design of acoustic performance for air-cleaner was presented and evaluated in this paper using a numerical simulation method and experimental method. A modified measurement was proposed in the paper to solve the problem of air flow noise caused by the original measurement layout. The modified measurement was proved to produce good results. A new study on the acoustic effect of filter was also developed here and noise reduction (NR) of the air-cleaner was predicted based on the study using the numerical simulation method. Actual intake noise was then predicted using the simulation method. Side branch silencers were designed to improve the acoustic capacity of the air-cleaner. The result shows that the newly optimized air-cleaner has a much better performance of noise elimination when engine operating.     

Study on the acoustic emission-model of concrete damage

I.lntroductiollBecausetherearethedefects.cracksandnon-homologousmicrostructurewithdifferentpropertiesincollcrete,whenaloadisputonconcretematerialthedamageandbreakagemayresultandsoonafterwardsexpanded.Itisadifficutproblem,howtodecidethedamageofconcretematerialwithcracksanddefects.TheacousticemissionisanassociatedphenomenollwiththeprocessofthenonhomologousdeformationorthebreakaeandexPansiollofmaterial.InthispaPertherelationshipbetweentheacousticemis8ionparametersandthedamageparameters,andthedam…     

薄板声谐振子扰动的声学特征检测研究

为进行快速ＮＤＴ，研究了薄板声谐振子扰动和声学特征变化的关系，用有限元方法分析在睡无缺陷薄板的振动频率和振型。利用数字信号处理技术，实验研究了样品中缺陷对声学特征的影响。实现和理论分析结果一致性很好。研究结果有助于正确利用样品声学特征进行无损检测。