By “too loud,” I don’t mean you can’t crank the Eagles, if that’s your thing. I’m talking about loudness as a measure of sound within a particular recording. Our ears perceive loudness in an environment by reflexively noting the dynamic range — the difference between the softest and loudest sounds (in this case, the environment is the recording itself, not the room you are playing it in). A blaring television commercial may make us turn down the volume of our sets, but its sonic peaks are no higher than the regular programming preceding it. The commercial just hits those peaks more often. A radio station playing classical music may be broadcasting a signal with the same maximum strength as one playing hip-hop, but the classical station broadcast will hit that peak perhaps once every few minutes, while the hip-hop station’s signal may peak several times per second.
A loud environment in this sense is one with a limited dynamic range — highs that peak very high, and lows that aren’t much lower. For decades, musicians and engineers have employed dynamic range compression to make recordings sound fuller. Compression boosts the quieter parts and tamps down louder ones to create a narrower range. Historically, compression was usually applied during the mastering stage, the final steps through which a finished recording becomes a commercial release.
In the predigital era, compression required a mastering engineer whose job is to create the physical master for the manufacturing process, to employ restraint and finesse. With digital audio, a few mouse clicks can compress the dynamic range with brute force. The result is music that sounds more aurally aggressive — like the television commercial.
During the 1990s, as digital technology infiltrated the recording process, some mastering engineers wielded compression like a cudgel, competing to produce the loudest recordings. This recording industry “loudness war” was driven by linked aesthetic and economic imperatives. A louder record grabs your attention — and will often be perceived, at least at first, to have better sound quality than a less compressed album — and musicians didn’t want their product to sound weak by comparison. Maximum loudness, it was thought, was a prerequisite for commercial success.