You may be confusing data compression with dynamic range compression, since you mention dynamic range. Dynamic range compression (limiting / brick wall limiting) has nothing to do with data compression, which is just referring to the removal of unnecessary data that is not noticeable from a psychoacoustic perspective (eg humans can’t hear above 24khz so that data isn’t needed, etc.) here is more info on DRC and MP3: http://www.tonestack.net/articles/digital-audio-compression/...