Suhas Sreedhar explains why the old Bruce Springsteen CDs that I’ve ripped sound so much quieter than newer tracks. The dynamic range of CDs (as opposed to vinyl) and digital signal compression technology made it happen.
In the 1980s, CDs were mastered so that songs generally peaked at about -6 dBFS [0 decibels full scale, the loudest point of the dynamic range] with their root mean square (RMS)—or average levels—hovering around -20 dBFS to -18 dBFS. As multidisc CD changers began to gain prominence in households toward the end of the decade, the same jukebox-type loudness competition started all over again as record companies wanted their CDs to stick out more than their competitors’. By the end of the 1980s, songs on CDs were amplified to the point where their peaks started pushing the loudness limit of 0 dBFS. At this point, the only way to raise the average levels of songs without having their loudest parts clipped—the digital equivalent of distortion, where information is lost because it exceeds the bit capacity—was to compress the peaks.
And as music players become smaller and more rugged (I moved from a sports-model water-resistant Walkman to a hard-drive-based iPod and aspire to a solid-state one), we’re taking them more places with us and we expect the music to be there. Music on the subway as the train rumbles through a tunnel is a commonplace now.
But the problem doesn’t just lie on the production end. If people are listening to songs in a noisy environment—such as in their cars, on trains, in airport waiting rooms, at work, or in a dormitory—the music needs to be louder to compensate. Dynamic-range compression does just that and more. Not only does it raise the average loudness of the song, but by doing so it eliminates all the quiet moments of a song as well. So listeners are now able to hear the entire song above the noise without getting frustrated by any inaudible low parts.
This might be one of the biggest reasons why most people are completely unaware of the loss of dynamics in modern music. They are listening to songs in less-than-ideal environments on a constant basis. But many listeners have subconsciously felt the effects of overcompressed songs in the form of auditory fatigue, where it actually becomes tiring to continue listening to the music.