Related to a previous post, I found an article on music + dynamic range:
"Britain’s leading studio engineers are starting a campaign against a widespread technique that removes the dynamic range of a recording, making everything sound 'loud.'"
“'Peak limiting' squeezes the sound range to one level, removing the peaks and troughs that would normally separate a quieter verse from a pumping chorus."
"Peter Mew, senior mastering engineer at Abbey Road studios, said: 'Record companies are competing in an arms race to make their album sound the ‘loudest’. The quieter parts are becoming louder and the loudest parts are just becoming a buzz.'"
"The brain is not geared to accept buzzing. The CDs induce a sense of fatigue in the listeners. It becomes psychologically tiring and almost impossible to listen to. This could be the reason why CD sales are in a slump."
I don't think this it the only reason CD sales and in slump, but I absolutely notice a difference between rock CDs produced after 2001 or so. Songwriting issues aside, there is something about modern production that just sounds wrong. Check out a previous post for a video demonstration.