Compression #6 - over-compression

With audio technology becoming more and more sophisticated, and the advent of digital audio in particular, some limitations of the analog world stopped being an issue and compressors and compression techniques started to be more and more used to try and grab the listeners’ attention.

We said before that given two identical sounds, if one is played louder it will sound better to our ears. There’s probably some anthropological explanation but the fact is that play something quiet, then follow it by something else louder and most listeners will prefer the louder part…

This is why compression was used more and more during airplay on TV and radio to try and bring out the commercials at a louder level than the movie or songs played before and after, as an attempt to capture the attention of the listeners.

The loudness war

Audio engineers and studios caught up with that idea and started to apply more and more compression to songs during the mastering phase. This is why most of the digital remasters done during the 90s for CD re-release were more compressed than the original. This went so far that it’s been coined “the loudness war” (more compression = more overall loudness).

For example, let’s have a look at a graph comparing an original with 2 remastered re-issues:

You can clearly see that the amount of compression applied went totally crazy. Now the problem with that is that a lot of details of the original were lost in the process. A lot of the transients were leveled, and everything is basically at the same level… There is a huge loss of dynamics (the difference between the loud parts and the quiet parts), when dynamics is what makes music. It’s hard to appreciate something loud all the time, it’s better if the music is flowing and there are ups and downs, quiets and louds…

Another thing to realize is that over-compression is fatiguing to the ears.

Remember that sound is basically air waves that are expanding and contracting and finally trapped by our ears. So, increasing the compression increases the air pressure sent into our ears. This can sound more immediately pleasing but in the long run it creates an ear fatigue that is pretty damaging and just plain boring.

In the next episode we’ll wrap up with some final thoughts about compression and why you should care. See you then!

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