This phenomenon was known before... (Score 1)

It started when radio stations began compressing the sound (not the MP3 way but compressing the dynamic range). People started to feel the difference between their CD's and radio stations so sound engineers began to compress the sound on CD's. If you want to hear the difference try: http://www.polskieradio.pl/sluchaj/ and choose "Dwójka" (it's the only major radio station that I know that does not use dynamic range compression - it's clearly shown when you record it and look at the waveform) and compare it to your favorite commercial radio station.