Standard test method for evaluating masking sound in open offices using a - weighted and one - third octave band sound pressure levels 用a加权和1 3倍频带声压级评价敞开式办公间掩蔽声的标准试验方法
Acoustics . hearing protectors . part 2 : estimation of effective a - weighted sound pressure levels when hearing protectors are worn 声学.听力保护器.第2部分:听力保护器损坏后a型加权声级有效性的评估
Acoustics - hearing protectors - part 2 : estimation of effective a - weighted sound pressure levels when hearing protectors are worn iso 4869 - 2 : 1994 ; german version en iso 4869 - 2 : 1995 声学.听力保护器.第2部分:当听力保护器磨损时有效a -
All kinds of methods measuring noise have been produced and a - weighting sound level is extensively used as a kind of fundamental measure in all of the world 针对不同环境下的噪声国际上提出了很多评价方法，目前为世界上广泛应用的是以a声级作为基本评价量的评价方法。
The nco limits are measured via the 30 - minute equivalent level in unit of a - weighted decibels ( db ( a ) ) , which is a commonly used international standard 该条例所订的声量上限是以每三十分钟时段内的平均噪音能量水平量度，以a加权分贝值为单位(分贝( a ) ) ，该准则为国际普遍采用的标准。
The key techniques are the introductions of a typical function transformation and a - weighted norm , which yield the uniform estimate with respect to the scaled debye length ) ，对任意的( 0 ， min { ， 2 } )都有我们应用的主要方法是能量方法，关键技巧是引入函数变换和-加权范数，使我们能够得到关于量级化德拜长度的一致估计。
So the validity of traditional objective - quantifiers in acoustics is being questioned . this is because the evaluation using db ( a ) criterion includes an a - weight filtering to compensate a sensitivity of human hearing 因此，传统a声级的实用性受到人们的怀疑，需要综合考虑人的生理、心理的影响，开展心理声学的研究，提出噪声质量的新的评价方式。
An under estimation of the hearing effects by the low frequency noise could be happened . that is to say , even if the a - weight sound level is small , the low frequency noise may annoy to listener by the different ways from the high frequency noise . so it is necessary to understand psychoacoustics in order to make noise quality evaluations that match the subjective experience of the purchaser 同时应用主观评价方法?成对比较法( paircomparisonstatisticalevaluationmethods )对不同家用空调器噪声进行主观评价试验，并与客观评价结果进行了对比，结果表明：人主观响应(烦躁程度)与各心理声学评价指标之间均具有很高的相关性，相关系数一般均大于0 . 9 ，而与a计权声压级之间的相关系数只有0 . 78 。
