In mastering music, especially Electronic stuff, you will always have to solve the problem that arises when your bass and your kick drum play at the same time. The combined amplitude can be enormous and very problematic if you run your final mix through a limiter like Voxengo Elephant (my personal favourite).
Enter side-chain compression. Put simply, this is when you compress the volume level of a track, but using a different track as the input signal for the compressor instead of the track being compressed.
It’s a very common technique to apply a compressor to the bass track and side-chain it to the kick drum. Every time there’s a kick, the volume of the bass dips.
One thing I love about Ableton Live is the shear ease of routing channels and setting up side-chain compression. As I couldn’t quickly find a way of doing this in FLStudio, and because I lack a decent VST compressor for the time being, I did this instead:
I select a region of the song that’s the same length as my drum pattern in the Playlist window, right click a control knob or fader (in this case the volume fader of my bass channel), and click Create Automation Clip. Then, I simply draw the curves that will quickly dip the volume of the bass on each kick of the drum pattern.
It’s a manual way of doing things and takes a bit more time, but the level of control and visual feedback is great. Plus, Automation Clips in FL can be drawn, duplicated, chopped and trimmed just like regular patterns and audio clips.