Compressor Settings for Mastering

Mastering CompressionMastering Compression

Compressor Settings for Mastering
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Back Stage Indie Report brings you another in our series of recording techniques!

In most Mastering situations you will be working with very different levels of each section of the song.  It’s important that you don’t compress away the natural dynamics of the music.  In a great many common situations, you should avoid using attack times that are too short.  Short Mastering attack times can cause you to lose important natural transient hits.  Generally, Mastering attack times range from 20ms to 100ms.  Look for release times between 200ms to 2,000ms ( 2 Seconds) and can even go to 5 seconds in some situations.  There is no one-size-fits-all answer, it is solely dependent on the music at hand. Dont worry if it is still confusing, it take practice and experience to determine these setting for a particular piece of music.

Lets Look At The Process…

Lets assume for the sake of this article that you are Mastering a typical commercial stereo track.

Your Kick track is usually the one that has the greatest influence on your compressor.

Are you able to hear the natural  rhythms? CAn you tap your foot to the beat?  It’s critical that you can so you are able choose the attack and release times.

For a starting point, set your ratio between 2:1 – 3:1.  Mastering should use low ratios as a “rule”.  You need to not overdo it or you can end up with that “pumping”effect (unless that is your goal).  There are producers that will want that “pumping” for dance and club music or remixes.  The technique we are going to discuss will make the compressor transparent and musical.

The quality of the compressor being used will dictate how hard you can push the ratio.  See Back Stage Indie report recommendations of compressors at varying price points below…

A good beginning setting for your attack ins around 40ms.  As stated earlier, this will be to short because it may damage the transient hits and reduce the punch of the song but its a good place to begin.  The final release setting will depend (mostly) on the rhythm of the track.  For now, lets just set it to 50ms.  Try to avoid using the “Hard Knee” when mastering.  The medium to soft knee will be more musically pleasing and wont sound as aggressive.   Start monitoring the track while slowly bringing down the threshold setting until you have a consistent state of attenuation.  YOu will hear a volume drop.  Start bringing up the make-up gain to get the overall volume to the original, pre compression, level.

If the attack is shortened too much, the song will lose its “punch”. If the attack is left too long, the compressor will take too long to engage and you will notice the attenuation lagging behind.  This also make the compressor obvious and not transparent.  Each song has its own “sweet spot”.  By experimenting around you will hear when its right.  Keeping in mind that you may need to work the “release” a bit before you can get the optimal attack.  If this sounds like a lot of variables and approximations, that’s because it is!  This is what separates the “art” from the “science”.

It’s the release time that gets the music moving!  If you set the compressor release too long, you will notice the falling behind and the attenuation will be obvious.  If you set it too short, you will notice the attenuation jump back after the transients.  The real sweet spot is where the release begins to compliment the attack. Imagine it swaying back and forth to the rhythm of the song.  There needs to be a back and forth tweaking of attack and release together to find that “sweet spot”.   Try to rely on your ears more than the meters.

Case Study
Here’s a way to visualise the attack and release in a mastering situation. Imagine just a kick and hi-hat. The kick happens every beat, the hi-hat on the 8th’s – all at about 100bpm. The kick’s level is above the threshold and so it will trigger the compressor but the hi-hat’s level is below. The kick triggers the compressor and can be noticed in the sudden reduction in the level of the hi-hats. As the compressor recovers, you would hear the hi-hat’s level gradually rise back up. In such a scenario, if the hi-hats where to arrive back at their full level before the next kick triggers the threshold (the release time being shorter than the time between each kick), then the result would be an awkward jump back to the full level. The awkwardness coming from their being no real significance at the point between each kick where the release time stops and the compressor stops compressing (unless you get it bang on half a beat or something). If the release was set to be only just longer than a beat, the compressor will still be in a state of compression when the next kick triggers the threshold. This takes away the awkwardness of the compressor jumping back and resting at no significant time, the result being smoother and more flattering to the music.
Obviously, the likelihood is that the music in question is probably much more complex than just a kick and hi-hat, and there will be a whole array of different sounds triggering the compressor at various times, but this concept can still be applied. Having the release that tiny bit behind the natural rhythm can give you a smoother, more flattering result.
Don’t Go Compressor Crazy!

It’s tempting to get a little compressor crazy.  Remember, at this point of the process, all the major individual tracks should have an appropriet amount of dynamuic range.  The Mastering compressor is only to polish the dynamic range of the blending of the individual tracks.  Generally, Mastering gain reduction sits around 3db.  Try putting the make-up gain down to odb to make sure you are not being too heavy-handed with the compression.  You want to avoid “Squashing” the track!  Maybe lesson the threshold to soften the effect and then bring the make-up gain back up to proper output levels.  Be careful that is you raise the threshold too much, certain elements in the track may not trigger the compressor at all.

The real transparency of this technique comes from the compressor moving in a natural way to the rhythm and so blends in with the musicality of the track. It’s when your settings are too harsh, aggressive, too fast or too slow that the compressor falls out of sync and exposes itself as being an artificial element in the music.

It’s important to remember that no compressor setting that fits all songs. The attack and release times will vary greatly from song to song. There’s no real mathematical computation that can give you the attack and release times simply based on the BPM of the song. It’s the feel of the rhythm.

Good Luck and Gods Speed!

Joemeek Compressor
Warm Audio
DBX Dual Compressor


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