Comment Loudness and Volume (Score 1) 636
are not the same. Volume measures pure energy levels (in Db) whereas loudness is based on psychoaccoustics. In particular the Fletcher-Munson curve http://en.wikipedia.org/wiki/Fletcher-Munson, which details the perceived response of humans to different frequencies at different volume levels. The supreme court was either ignorant or corrupt when they said that it is not possible to measure "perceived loudness". Measuring devices for this have existed for quite a while. There is a similar problem with songs prepared for radio play. In order to attract attention producers boost the loudness of the cuts, leading to an overall lowering of quality (namely dynamic range) for pop songs.