Hypercompression Revisited

As mentioned in the last post about the sound of Metallica's new record thanks to over-compression (hypercompression as some mastering engineer's call it), it's important to know how and why the process started.

The loudness wars have been going on since pop radio began in the 50's. If a record sounded louder than the one that just played over the airwaves, many listeners would perceive it as "better", so the labels were always trying to make their records louder as a result. Since the music delivery method at the time was a vinyl record, there was a built-in physical limitation to just how loud you could ultimately make it. Make it too loud and the stylus would rattle right out of the grooves and the consumer would ask for his money back, so hypercompression never became an issue during this period.

This physical limitation to level essentially went away with the introduction of the CD in the 1982, but the level war broke out again in an unforeseen way. There used to be a weekly compilation of singles from all the major labels that was sent to radio program directors in the 80's. When a label heard one of their songs that sounded quieter next to another on the compilation, they would freak out and demand that the mastering engineer on the next record pump up the level so it was at least equal to the loudest track on the CD. As a result, a loudness war broke out to an even greater degree than it was with radio.

Just to see how we've come to this commonplace hypercompressed era, take a look at some graphic excerpts from my book "The Mastering Engineer's Handbook" that illustrate this perfectly.

Here are waveforms from a typical hit record from 1985, 1995 and 2005. Notice that the '85 waveform is not too loud and there's plenty of peaks and valleys indicating a fair amount of dynamics. The '95 waveform is a lot louder but still has some dynamics to it. The 2005 version is starting to look like a square wave, with hardly any dynamics. And as we approach 2009, it's even worse and looks just like a solid block. It's become quite an art to make something like this sound even remotely good.

Be cautious when pumping up the level on your songs as it comes with a price. You may make it louder but studies by broadcasters have shown that the listener generally hates the hypercompressed sound and won't listen for long!