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There are a lot of different opinions when it comes to using compression on your mixes, specially because the way that you use compression (and many other tools and plug-ins) depends entirely on each individual sound you are applying it to. In this quick tip we are going to focus on gaining a compressor on your output track. After all, it is one thing to make your track sound 'louder', but that does not necessarily make it sound 'better'.
It has been suggested that, when you work on a mix, you do it against a compressor on your output track. As useful as this suggestion might be for some, it does not work for others and, at the end of the day, it is your choice whether to mix against a compressor all the time or add the compression towards the end of your mixing workflow. However, there is a very useful tip I learnt for working with gain and compression on the output track.
Think About the Dynamic Range
The dynamic range of a track is an essential part of what makes the track interesting and keeps the music 'breathing'. Graphically speaking, you could see the dynamic range of a track by looking at the volume faders on the channel strip. As you play the track notice how the signal level goes up and down, increasing and decreasing, peaking at certain points. The importance of thinking about this relies in the fact that the track should still have a good dynamic range after it has been compressed.
Understanding the Compressor Gain
It is important to bare in mind that the Gain parameter in the compressor regulates the amount of volume that gets into the compressor. Therefore, if you are working on a mix that has been kept at a low volume level and, when applying compression to it, you increase the compressor's gain, you are effectively making it louder but not necessarily better. It is a very valid option to increase the gain in the compressor but, most of the time, this results in a loss of dynamic range.
Notice that, if you have increased the compressor's gain a fair amount, and the compressor is showing around 6 dB or more of gain reduction, the signal levels in the channel strip have very little, if any, dynamic range.
So in order to make sure you get the best out of your compressed sound, you have to make sure you don't increase the gain too much. From experience, I would suggest never to have over 6 dB of gain reduction.
The Problem at Hand
Manipulating the compressor's gain is a common way of making your track louder. However, this approach can become problematic. By increasing the compressor's gain you can really hear the difference in volume and, for that same reason, it is really hard to judge any difference in the quality of your sound.
In other words, when you try to compare the original sound and the compressed sound (by bypassing the compressor while playing the track) the only noticeable change is that the track just sounds louder. This, as you'd imagine, could be very misleading.
The Gain Plug-in
So, in order to apply compression to a sound while making sure it's making it both louder and better, it is recommended to use the gain as a separate plug-in, before the compressor. Logic's gain can be found under the Utility option in the plug-in pop up menu.
Increase the gain until you get a reasonable amount of volume, making sure it doesn't peak above 0 dB. That should leave a good dynamic range. Then apply the compressor and notice that you don't need as much gain reduction to be applied.
By using the gain separately from the compressor you have overcome the loudness issue. As you compare the compressed sound to the original, by bypassing the compressor, you will be able to hear the actual compression and not just loudness. Hence, making sure that the work you are doing is actually making the sound better.