In real life a folk singer isn't as loud as a rock band, but once her recording is compressed she might be as loud as Metallica. Of course, with most types of music the sound isn't turned up to 11 all of the time.
There are quiet passages, and only the loudest parts, like the hardest drum hits, are really loud. We have the technology to accurately record music, but few record companies choose to make lifelike recordings.
The Loudness Wars refers to mixing and mastering techniques that squash music's natural soft-to-loud dynamics. Obviously, you can control the playback volume of your tunes, but once the engineers compress the sound, there's no way to restore the true dynamic range. This problem doesn't just affect obscure records; Grammy Award-winning CDs, like Arcade Fire's "The Suburbs" suffer from loud-all-the-time compression. I love their music, but I find "The Suburbs" hard to listen to. Before we go any further, I'm not referring to MP3 "lossy compression," that's a completely different malady. If you listen to downloaded or streaming music, chances are you're getting the worst sonic effects of dynamic and lossy compression!
I attended the "Loudness Wars: The Tides Have Changed" workshop at the Audio Engineering Society's recent NYC convention to gain greater insight about the trend. Stereophile magazine's John Atkinson was on the panel, and he used the Red Hot Chili Peppers' "Californication" album to illustrate the problem. When he measured that CD he discovered it had very little dynamic range--just 4 decibels--but the Beatles albums recorded decades earlier have 11 to 14 dB of dynamic range! You would have thought newer recordings would always be technically superior to older ones, but that's not the case. Atkinson also showed the waveform of Pink Floyd's remastered "Money" from 2003, and how the remastered version crushed the original dynamics of the tune recorded 30 years earlier. You might ask why would the engineers do that, why make it sound worse? To make it loud all the time.
When I asked mastering engineer Bob Katz about how the use of compression has changed over the years, he summed it up this way, "I'd estimate, since the invention of the compact disc about 10 percent of the releases from 1980 through about 1993 were overcompressed. Then, from 1993 through 2000 a very exponential curve reaching probably as much as 60-70 percent of all rock recordings were affected. If you look at teens and 20 something demographics, maybe 90 percent of the current stuff they listen to is overcompressed or hypercompressed."
That's sad news indeed, but Katz was on that AES panel and he discussed a possible Loudness Wars cease-fire that would involve the widespread adaptation of an automatic volume adjustment technique known as normalization (Apple's Sound Check is such a system). This currently in use process isn't perfect, but Katz expressed the hope that future processors will be better. These normalizing algorithms don't merely squash/compress music's dynamic range, no, they're more sophisticated than that and process long-term dynamic attributes. Katz expressed the hope that when these normalization techniques are perfected, highly dynamic music will be able to coexist with heavily compressed recordings in your music player. The dynamic recordings won't sound too "quiet" when played in shuffle modes, side-by-side with heavily compressed tunes. When truly sophisticated normalization becomes a reality, record producers will be less inclined to overcompress the music. At least there's some hope the record companies will back off on overcompression in a few years.
So sure, most of the new music you listen to right now is crippled by overcompression, but that's not a big problem when you're listening over inexpensive earbuds or computer speakers. You're in effect sheltering your ears from the compression onslaught. I've tried to explain the Loudness Wars with words, but it's a lot easier to understand the problem with images and sound. This video should help clarify the concept.
Now, more than ever, paying for recorded music is a purely voluntary act. And judging by the sound of too many contemporary recordings' quality, it's not worth much.