主题：今天上课的几个问题

Note that the "A" weighting scale is an attempt to compensate for non-linearities in average human hearing perception when compared to acoustic measuring devices such as SLMs, frequency sapectrum analyzers and other machines. It is an educated approximation based on the research of Munson & Fletcher.

弗莱彻—芒森曲线 1933年

You will see lots of references to equal loudness curves or equal loudness contours. These are based on the work of Fletcher and Munson at Bell labs in the 30s, or perhaps refinements made more recently by Robinson and Dadson. These were made by asking people to judge when pure tones of two different frequencies were the same loudness. This is a very difficult judgement to make, and the curves are the average results from many subjects, so they should be considered general indicators rather than a prescription as to what a single individual might hear.