Tips To Avoid Over-Compressing Your Audio

Audio compression is when only the loudest parts of an audio file are turned down when the rest of the audio file is left alone.  The best use of compression (and arguably the reason it was invented as an audio effect) is when there are only a few bits here and there in an audio file that are quite loud when the rest of the audio seems to bunch around an average volume.

Here is a metaphor.  You're carrying a fully extended mic stand (say 4 feet long) into another room with a doorway that is 3 feet wide.  Your body is only about 2 feet wide (maybe a bit more in placed we don't want to admit:)), so without the mic stand held cross-ways in front of you, your body would easily fit through the door.  But the mic stand is preventing you.  The solution is pretty clear.  You only need to reduce the size of the mic stand (let's pretend you HAVE to carry it cross-wise for some reason - buy into the world of the metaphor) to less than 3 feet in order to get both it and your body through the doorway.  Well, since a mic stand can easily be shortened, you simply loosed the fittings and collapse it.  bingo!  Now you both fit.  In fact you could even be much fatter and you could both still fit into the door!

A compressor (used to be an electronic box and now more commonly a program) often affects more than just the few problem bits of audio.  People discovered that they could make thing sound better if they were louder, so they started compressing everything and really squishing so that they could turn EVERYTHING up very loud without a little mic stand here and there preventing it.  That's like deciding "wow, I've got a lot of room now that the mic stand is so small, so I can actually be much fatter and still fit through the door.  Let's eat Haagen Dazs!

Whether the metaphor makes sense or not, the point is that compressor abuse is pretty common.  But it turns out that just because things may sound better at first when they are made louder, there are often losses in balance and certainly of dynamic range when too much compression is used.

Here is an article that gives a tip or two on how not to assume the audio is better just because it's louder, and how to check to see how much life you sucked out of your audio post-compression by matching the levels of compressed and uncompressed versions.


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