Mixing the bass and kick is one of those things that are said to be hard. Pretty hard. People say you can tell the men from the boys by taking a listen to the relationship between their bass tracks and kick drum hits. And some other silly things with just a little bit of truth to them. The truth is (as usual), it depends. The shady truth. In most cases, mixing these two instruments is not that hard. Not as hard as many scared, inexperienced “engineers” will lead you to believe. A couple of things come up from time to time regarding mixing the bass and the bass drum. Hopefully, you’ll realize that some of it is snake oil, just like many other things in audio.
The mirrored EQ boost/cut myth
You have probably read about it at least once, when you read about mixing the low frequencies. Boost the kick drum by a couple dB somewhere in the lows, and cut the bass by the same amount at the same frequency. Is it utter bullshit? No. It’s just pretty useless. And unnecessary as well. Let’s review the basics of it all again. A good mix comes from simple things. Among these, the most important ones are: good arrangement, and good sounding recordings. Once these are given, you will rarely if ever run into a pro mixing engineer reaching for the above trick. It’s because if you think about it, the kick drum and the bass are different instruments. With different characters and traits. Even if they both happen to function mainly in the bass range. A kick is just that, a short, hitting sound, with a peak and not much else. A bass line usually consists of long, legato sounds, comparatively. So you set their levels and that’s it, man.
Rolling off low end
It’s a quick and easy way to make both your bass line and the kick track lose low end energy. In extreme cases, they’ll end up sounding weedy, thin and lifeless as well. If there’s excessive rumble in the low frequency instrument tracks, they weren’t recorded properly. That being said, rolling off 25 – 30Hz with a hi-pass or low shelf is about as high as you’ll ever need to go. For safety reasons only. Don’t hurt that low E (~ 41Hz) of a bass guitar or upright. That scared you about the low B of a five string, right? It should have.
Ducking the bass, so the kick can be heard
Ducking is a technique that gets mentioned often when it comes to getting a good mix balance between the bass line and the kick drum. Not deservedly so. Side chaining a compressor to tame the bass during every bass drum hit is doing it the hard way. The easy way is to balance the levels of the two correctly, so you don’t need this trickery. In some rare cases, this stuff comes handy, but more like an effect, not a staple.
Subtle EQ can do the trick
The little you can do to enhance the kick and bass tracks is just a touch of EQ. Usually a boost on both tracks, to bring out their character and add definition. Some “click” in the kick, and some “growl” in the bass track. Old school? You betcha. But it works.