I've heard some engineers recently talking about the kick and the bass always being in a fight and one of them having to win. That struck me as kind of a foreign concept until I started working at my current gig. The subs are pretty small and have a limited amount of power available to drive them. Frequently the bass would have to win out in order for everything else to sound right and I'd make do with mostly beater sound from the kick. It was a shame though because every time I heard the kit by itself I always thought it sounded pretty darn good (even if I do say so my self).
I had resigned myself to my fate and hoped that some day we'd revamp the system. Then I finally landed on an idea that's used a lot in mixing records, particularly dance records where both elements have more of a lead role than they do in other types of music. Using the side chain on a compressor on the bass channel.
Side chaining, for those not familiar, is a method of making a compressor respond to something other than the signal going through it. Normally, signal goes in and gets split. Half of the signal goes through a detector that tells the compressor when to engage based on the settings you've given it, and the other half is processed and fed back into the console. Using the side chain allows you to use something besides the signal being processed to engage the process.
For example, in my case, I could take a direct out from the kick channel and feed it into the side chain of the compressor on the bass. Whenever the kick hits, gain is reduced on the bass channel, effectively making some space for the kick to come through in the mix. How much space is determined by the settings I choose. Go too deep or too long and it will be obvious and sound bad. But get the settings dialed in right and the kick should just come through nicely in the mix without sounding like it's punching holes in the bass line.
One further benefit of using this technique is that if your drummer and bassist aren't always exactly together, if the kick is coming up through the bass on downbeats it will obscure that tiny bit of difference by being higher in the mix. The bass is still felt and still present, but with the kick controlling it rhythmically you get a tighter performance.
Tune in next time Brethren of the Knob and Fader, when maybe I'll remember to write about how to use side chaining to de-ess a vocal.