A Visual History of Loudness: Christopher Clark graphed the peak levels and RMS level of three hit songs from every year since 1979 to illustrate the rising use of compression in music production. Also on the chart is a nice discussion of dynamic space and perceived loudness. Related NPR article. Coincidentally, I just made an appointment with my ear doctor to get custom earplugs made.(Thank to Ben Chun for pointing out the article.)
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