共查询到20条相似文献,搜索用时 15 毫秒
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为了确定地下餐饮空间内使用者主观声舒适度可接受时的声压级阈值范围,本文选取典型的封闭式地下餐饮空间作为研究对象,采用实地问卷与实测相结合的方法进行调研。结果表明:地下餐饮空间内整体环境舒适度主观评价偏低,声舒适度评价与整体环境舒适度评价具有强相关性,因此声环境是影响地下餐饮空间内整体环境舒适度的因素。在影响主观声舒适度评价的客观指标中,混响时间可不作为主要影响因素考虑;而背景噪声声压级是影响地下餐饮空间内声舒适度主观评价的重要指标。使用者声舒适度为可接受时,地下餐饮空间内背景噪声声压级阈值为70-75 dB(A)。 相似文献
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Acoustic comfort evaluation in urban open public spaces 总被引:1,自引:0,他引:1
W. Yang 《Applied Acoustics》2005,66(2):211-229
This paper presents the results of an intensive questionnaire survey and objective measurements on soundscape, aiming at the evaluation of acoustic comfort in urban open public spaces. From summer 2001 to spring 2002, 9200 interviews were made for four seasons in 14 urban open public spaces across Europe. The results suggest that the subjective evaluation of the sound level generally relates well with the mean Leq, especially when the sound level is below a certain level, which is 73 dBA on the basis of this study. However, considerable differences have been found between the subjective evaluation of the sound level and the acoustic comfort evaluation: people tend to show more tolerance in terms of acoustic comfort evaluation. The background sound level has been found to be an important index in evaluating soundscape in urban open public spaces - a lower background level tends to make people feel quieter. Analyses of individual sound elements show that the acoustic comfort evaluation is greatly affected by the sound source type - introducing a pleasant sound can considerably improve the acoustic comfort, even when its sound level is rather high. No significant difference was found among different age groups in terms of subjective evaluation of a sound level, whereas in terms of acoustic comfort, there were significant differences. 相似文献
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This paper proposes the use of a simplified analytical model to evaluate acoustic conditions in restaurant dining rooms required for ensuring the intelligibility of conversations. The model is useful for design applications and is suitable for evaluating the maximum number of speakers present in a restaurant room in order to ensure intelligibility of conversations taking place at each table in the presence of background noise caused by conversations at other tables. The maximum number of speakers is studied in relation to the sound level difference between useful and disturbing sound, sound absorption of the room, and the average speaker–listener distance. The model is applied to the case of a dining hall in a multipurpose centre, which is currently in the planning stage. 相似文献
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An initial attempt has been made to understand factors that determine acoustic comfort for cruise ship passengers. Although no literature directly pertinent to the question could be found, use of elements from studies on railways coaches in a questionnaire administered to shipbuilder and sub-contractor professionals on board during sea trials was judged a relevant initial approach. The questionnaire, consisting of closed questions followed by open questions, was drawn up to assess acoustic comfort in relation to others factors (such as temperature or light) and to identify the main conditions causing acoustic discomfort. During two sea trials 100 questionnaires were completed. Acoustics, then temperature, are pointed out as the first two comfort criteria and the priorities for improvement. Creaking and squeaking noises, noise of engines and whistles from HVAC are the main reported causes of annoyance. The results of the investigation demonstrate the prominent role of acoustics in respect of ship-board comfort. 相似文献
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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. 相似文献
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《声速测定》是大学物理实验中比较普遍的一个综合性实验。在声速测定实验仪的基础上,改进了信号源,并制作了声悬浮配件,使其实现既可以用多种方式测量声速,又可演示声悬浮实验现象。声悬浮及声速测定实验仪悬浮稳定性强,声速测定准确,仪器造价低,使用方便,这样设计节省了实验室资源和空间。 相似文献
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《Comptes Rendus Physique》2016,17(5):524-532
We provide theoretical and numerical analyses of the behavior of a plate-type acoustic metamaterial considered in an air-borne sound environment in view of sound mitigation application. Two configurations of plate are studied, a spring-mass one and a pillar system-based one. The acoustic performances of the considered systems are investigated with different approaches and show that a high sound transmission loss (STL) up to 82 dB is reached with a metamaterial plate with a thickness of 0.5 mm. The physical understanding of the acoustic behavior of the metamaterial partition is discussed based on both air-borne and structure-borne approaches. Confrontation between the STL, the band structure, the displacement fields and the effective mass density of the plate metamaterial is made to have a complete physical understanding of the different mechanisms involved. 相似文献
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本文介绍在数字声学测量分析系统中,通过双传声器信号互谱密度的计算进行声强及声功率测量的基本原理。该数学分析系统由微计算机,数字信号处理卡和A/D变换卡组成。在一个数字系统中,通过快速傅里叶变换(FET)进行互谱计算是十分有效的。本文着重介绍了,在声强的测量分析中对声强探头两传声器的固有相位差进行补偿的重要性和补偿方法,这是声强测量的重要环节。 相似文献
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Factors influencing the sound preference in urban open spaces 总被引:1,自引:0,他引:1
Lei Yu 《Applied Acoustics》2010,71(7):622-633
In this paper, based on a large scale survey in Europe and China as well as corresponding laboratory studies, the influencing factors on the sound preference evaluation, considering social, demographical, physical, behavioural and psychological facets, have been systematically examined based on statistical analyses for each of the 19 case study sites. Various sound types have been considered, including natural, human, mechanical and instrumental sounds. In terms of social/demographical factors, the results suggest that age and education level are two factors which universally influence the sound preference significantly, although the influence may vary with different types of urban open spaces and sounds. With increasing age or education level, people tend to prefer natural sounds and are more annoyed by mechanical sounds in general. It has also been found that gender, occupation and residence status generally would not influence the sound preference evaluation significantly, although gender has a rather strong influence for certain sound types such as bird sounds, especially at certain case study sites. In terms of physical factors (season, time of day), behavioural factors (frequency of coming to the site, reason for coming to the site), and psychological factors (site preference), generally speaking, their influence on the sound preference evaluation is insignificant, except for limited case study sites and certain sound types. The influence of home sound environment, in terms of sounds heard at home, on the sound preference has been found to be generally insignificant, except for certain sounds. It is noted that there are some correlations between social/demographical factors and the studied physical/behavioural/psychological factors, which should be taken into account when considering the influence of individual factors on sound preference. 相似文献
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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. 相似文献
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Laurent Galbrun 《Applied Acoustics》2011,(4):205-209
This paper examines space averaging methods applied to structural level differences measured in lightweight building structures (two beam junction and single plate and beam junction). The methods studied include the averaging assuming a constant input force, the averaging based on a constant vibration level across the source element, and the arithmetic averaging of level differences. Tests indicate that a fairly steady input force can be easily produced when using an impulsive source such as a hammer; the constant input force method is then appropriate and can be used to space average level differences (the two beam structure showing a standard deviation of 0.1 dB from the averaging based on levels normalised to the force). On the other hand, acceleration levels can exhibit significant variations with position due to the low mode count and modal overlap of some lightweight elements such as timber beams. Variations in the vibration level across the source element can then be responsible for large inaccuracies in the level difference calculated from the constant level assumption, the two beams’ results showing errors greater than 5 dB at several 1/3 octave band frequencies. The latter averaging method is then inappropriate and should not be used. 相似文献
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During ultrasound-induced cavitation in liquids, acoustic emissions at fundamental and harmonic frequencies can be detected. The effect of acoustic emissions at harmonic frequencies on the sonochemical and sonophysical activities has not been explored, especially in large-scale sonoreactors. In this study, the acoustic emissions in the range, 0-250 kHz in a 36 kHz sonoreactor with varying liquid heights were studied and compared with the sonochemical activities. The acoustic pressures at both fundamental and harmonics decreased drastically as the liquid height was increased due to the attenuation of sound energy. It was observed that the increase in input power resulted in only an increase in the acoustic emissions at derivative frequencies such as, harmonics and subharmonics. The sonochemical activity, evaluated in terms of sonochemiluminescence and H2O2 yield, was not significantly enhanced at higher input power levels. This suggests that at higher power levels, the “extra” acoustic energy is not effectively used to generate primary cavitation activity; rather it is converted to generate acoustic emissions at harmonic and subharmonic frequencies. This is an important observation for the design of energy efficiency large-scale sonochemical reactors. 相似文献
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This paper investigates mutual influence of duct and room acoustics in the whole fan-duct-plenum-room integrations. Applying the parametric design language of finite element software ANSYS (APDL), dimensional and positional influence on system acoustics has been studied. Models with different room dimensions, duct lengths, duct cross-sections, duct locations, duct discharges and duct elbow were constructed, and their characteristics were compared qualitatively. Results show that small rooms, short ducts, large duct cross-sections and bell mouth duct discharges help to increase room sound pressure levels (SPLs); SPLs in ducts and plenums are sensitive to duct dimensions and duct discharge types but insensitive to duct locations and room dimensions; duct elbows have relatively indistinct acoustic influence in each component. Based on the calculation results, a semi-experimental method was proposed for simply and approximately evaluating indoor acoustic spectra of fan-duct-plenum-room integrations, then an example was used to demonstrate the prediction process. Finally, by adopting several ideal models, sound field constitutions, duct and room wall admittances and duct end reflection were explored quantitatively. This study may give a detailed understanding of fan-duct-plenum-room acoustics for researchers, also it might provide a new, simple and approximate prediction method for professionals to evaluate and improve fan-ducted acoustics. 相似文献
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R.S. Ming 《Applied Acoustics》2005,66(9):1074-1087
In this paper, a novel acoustical barrier based on the principle of the Helmholtz resonator is proposed for the mitigation of tonal noises and its in situ performance has been assessed in comparison with a reflecting barrier and an absorbent barrier. For a lightly damped thin-walled reflecting barrier, the energy transmitted through the barrier structure is comparable with that diffracted over the edges. The absorption treatment not only absorbs acoustical energy but also damps the barrier structure resulting in a negligible energy transmission. The results demonstrated that for tonal noises the proposed barrier is more effective than reflecting and absorbent barriers. 相似文献
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