从建筑声学到环境声学

本文简述环境声学的发展过程以及在厅堂音质、环境噪声和噪声控制方面的新世纪展望。     

科特迪瓦共和国剧场声学设计与缩尺声学模型试验

科特迪瓦共和国剧场包括主演出厅、第二演出厅、排练厅和各种配套用房。此外还有科方自建的露天剧场,它构成了供和国首都阿比让市的演出中心,由于三个厅室各有其主要功能、且音质要求较高,故分别进行了声学设计,并对其中的主演出厅作了缩心声学模拟试验,以弥补声学计算上的不足,本报告简述共和国剧场各厅声学设计指标的确定,以及为达到预期声学效果所采取的各项技术措施。     

中国音乐学院琴房楼的声学设计和评价

中国音乐学院琴房楼是该各系学生个人琴的场所,楼内六层建筑共设１９８间琴房,房间面积小,又相互毗邻,因此,如何使小室获得良好的音质,又能避免相互间的噪声干扰,是声学设计的关键所在,本文着重介绍通过中国音乐学院琴房楼的工程实践,对解决上述问题所取得的成效。     

杭州剧院的声学模型试验

杭州剧院是一座多功能厅堂,观众厅的体积约10000m³,能容纳2000观众席,已于1978年9月竣工使用,观众反映音质效果比较好。在我们进行音质设计过程中,为了及早对设计方案作出评价,作了1:10的声学模型试验。本文概括给出某些试验的结果,并与剧院建成后实测进行比较。模型试验包括(1)木条子墙和“船形”扩散体天花的声学特性,(2)吸声材料的模拟,(3)混响时间,(4)反射声,(5)声场分布,(6)观众对前次反射声的影响,(7)方向性扩散,(8)清晰度,(9)主观评价。模型和实物的对比结果:满场的混响时间除250Hz的差别较大外(约20%),其余频率比较接近(差别少于10%);反射声图形是相似的;声场分布的差别少于2dB;观众对从台口侧墙来的前次反射声有影响,衰减约6dB;方向性扩散低于实测值,这是由于制造模型时省略一些细部所引起;清晰度和主观评价与观众的实际感受大致相符。     

我国建筑声学的20年回顾与展望

我国建筑学声在近20年间,无论在科研、设计、声学材料（结构）的研制、生产和应用方面均有较大的发展。在厅堂音质设计的个别领域还取得了突破性的进展。本文就上述几方面作概要的介绍。     

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。     

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。     

北京长城全周影院的音质设计

一种具有大影像、３６０度水平视野、接近于全方位的立体声效果,以高保真的声画环境将观众包围,使观众产生强烈临场感的全周影院在国际上也为数不多,而在我国建造更是一种新的尝试。本文通过介绍北京长城全周影院的音质设计和声学性能的测试说明,虽然这种新电影系统与常规电影有明显区别,具有很多特殊要求,但通过建筑、声学光学设计者的共同努力及密切配合,最终获得了视听性能的满意的结果,使影院达到了国际先进水平,也为全     

中型多功能体育馆声学设计的探讨

本文从应用角度探讨了中型多功能体育馆声学设计中的一些问题,并提出了一些有用的经验数据和建议。     

Evaluation of the acoustic performance of a modular construction system: Case study

The aim of this technical note is to characterize the value of acoustic treatments applied to sustainable buildings. The technique is not common in Brazilian construction, but the market needs construction techniques like the ones that will be showed here. At the end of the article, a comparison between masonry with concrete blocks and the industrialized system (built in steel framing) is presented. The simplified method of measuring acoustics was chosen, to be as close as possible to the regular engineering method. The tested buildings have been classified accordingly. This project made use of the Brazilian law and some European laws.     

Bonding and impedance matching of acoustic transducers using silver epoxy

Silver epoxy was selected to bond transducer plates on glass substrates. The properties and thickness of the bonding medium affect the electrical input impedance of the transducer. Thus, the thickness of the silver epoxy bonding layer was used as a design parameter to optimize the structure for the transducer input impedance to match the 50 Ω output impedance of most radio frequency (RF) generators. Simulation and experimental results show that nearly perfect matching is achieved without using any matching circuit. At the matching condition, the transducer operates at a frequency band a little bit below the half-wavelength resonant frequency of the piezoelectric plate. In experiments, lead titanate (PT) piezoelectric plates were employed. Both full-size, 11.5 mm × 2 mm × 0.4 mm, and half-size, 5.75 mm × 2 mm × 0.4 mm, can be well matched using optimal silver epoxy thickness. The transducer assemblies demonstrate high efficiency. The conversion loss from electrical power to acoustic power in soda-lime glass is 4.3 dB. This loss is low considering the fact that the transducers operate at off-resonance by 12%. With proper choice of silver epoxy thickness, the transducer can be matched at the fundamental, the 3rd and 5th harmonic frequencies. This leads to the possible realization of triple-band transducers. Reliability was assessed with thermal cycling test according to Telcordia GR-468-Core recommendation. Of the 30 transducer assemblies tested, none broke until 2900 cycles and 27 have sustained beyond 4050 cycles.     

穿孔管消声器声学长度修正的理论公式

推导出穿孔管消声器声学长度修正以及共振频率的理论公式。证明了在均匀分布情况下,多小孔向膨胀腔声辐射与单个小孔向膨胀腔声辐射的声学长度修正系数是一致的。对于小孔向主管道的声辐射,根据理论公式研究了穿孔率、周向均布数以及亥姆赫兹数对声学长度修正的影响,有限元计算得出在直径比小于0.4的情况下声学长度修正系数理论公式与仿真计算结果吻合良好。并利用理论公式的性质以及仿真结果获得了实用的拟合公式,提升了穿孔管消声器在高频时共振频率的计算精度。     

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．     

Analysis of liner performance using the NASA Langley Research Center Curved Duct Test Rig

The NASA Langley Research Center Curved Duct Test Rig (CDTR) is designed to test aircraft engine nacelle liner samples in an environment approximating that of the engine on a scale that approaches the full scale dimensions of the aft bypass duct. The modal content of the sound in the duct can be determined and the modal content of the sound incident on the liner test section can be controlled. The effect of flow speed, up to Mach 0.5 in the test section, can be investigated. The results reported in this paper come from a study to evaluate the effect of duct configuration on the acoustic performance of single degree of freedom (SDOF) perforate-over-honeycomb liners. Variations of duct configuration include: asymmetric (liner on one side and hard wall opposite) and symmetric (liner on both sides) wall treatment; inlet and exhaust orientation, in which the sound propagates either against or with the flow; and straight and curved (outlet is offset from the inlet by one duct width) flow path. The effect that duct configuration has on the overall acoustic performance is quantified. The redistribution of incident mode content is shown, in particular the mode scatter effect that liner symmetry has on symmetric and asymmetric incident mode shapes. The Curved Duct Test Rig is shown to be a valuable tool for the evaluation of acoustic liner concepts.     

Sound radiation of panel-form loudspeaker using flat voice coil for excitation

A novel panel-form loudspeaker in which the panel of the speaker is excited by the forces generated through the flat voice coil of a rectangular electro-magnetic type exciter for sound radiation is presented. The exciter when properly designed has the advantage of exerting appropriate loads to the panel so that the major sound pressure level (SPL) dips of the speaker can be suppressed or even eliminated. For designing such panel-form speaker, a method formulated on the basis of the classical plate theory (CPT), Ritz method, and first Rayleigh integral is proposed for predicting the SPL curve of the speaker. An experimental investigation was performed to verify the feasibility of the proposed method. The effects of some system parameters on the major SPL dips of the proposed panel-form speakers are investigated by means of several numerical examples. The optimal locations of flat voice coils for exciting several panel-form speakers are determined to illustrate the important role of excitation location for enhancing sound quality of such speakers via the removal or suppression of the major SPL dips.     

Acoustical design of stages with large plane surfaces in rectangular recital halls

Effects of architectural features on stage acoustics for rectangular recital halls were evaluated based on acoustical simulations using Odeon 4.01 software. Variables included volume, splaying angle of perimeters, proportion, location and orientation of the performer, and detached reflectors. All surfaces were plane and relatively large. As a result, a 920-m³ wedge-shaped stage yielded a −12-dB early-to-direct energy ratio (ED80) and early support (STearly) as suggested by Gade. Besides reducing stage volume, early energy was enhanced by reducing the splay of stage envelope, reducing stage width, moving the source towards the back of the stage, and placing detached reflectors. For late energies the shape played a more important role than did the volume. No echo was found unless a trumpet source was used. The results provided alternative ways to control on-stage acoustics in recital halls.     

基于PC机的一种多功能声显微镜及可视化技术的研究

近来研制成功了一种基于ＰＣ机、我们称为“ＴＨＳＡＭＭ”型的多功能声显微镜。在ＰＣ机内插入采样率１ＧＳＰＳ的超高速Ａ／Ｄ卡和信号产生和接收卡,利用软件完成信号检测、处理、显示功能。仪器工作频率为１－１００ＭＨｚ;在检测样品时,同时多层显示Ａ、Ｂ、Ｃ扫描结果。根据声学理论、Ｍａｒｃｈｉｎｇ Ｃｕｂｅ等值面抽取方法和ＯｐｅｎＧＬ技术完成了三维数据的可视化处理,显示样品的内部三维结构。该系统已成功应用于多