1. Use an EQ
Almost every base drum consists of two important frequency bands. The bottom of a classic base drum ranges between 65 and 110 Hz, and the top ranges between 3 and 5 kHz (sometimes 8 kHz). The bottom and the bass are two of the major components that will give your song/beat more punch, but oftentimes they get in the way of each other. To avoid that, apply a low-cut to your base drum, somewhere between 30 and 60 Hz. The bottom is where every base drum should have its heart, so adjustments in this band have to be made with caution.
Many base drums serve no practical purpose between 120 and 350 Hz, so you can lower this band by applying a bell filter. The top can get in the way of other instruments (e.g. toms), so it can be useful to reduce it, but oftentimes the top makes a specific base drum sound unique. Experiment and adjust it to your needs. If you like to add a second or third base drum, that’s ok, just keep in mind that every base drum claims certain frequencies and needs room to develop.
Add a compressor to reduce unwanted peaks, but don’t try to force your base drum into the mix by compressing it too much. Play around with the attack time of your compressor. Sometimes, longer attack times can improve the base drum’s percussiveness and enhance its positioning within the rhythmic structure.
Pitching your base drum can help your base drum fit the rest of the drums, and the rest of the song/beat. It can also help to fit your snare drum, and vice versa. Base drum and snare drum are like the yin and yang of your drums. They have to be complementary! Keep in mind that pitching can change the whole “essence” of your base drum, so you might need to EQ afterwards.
First off, be careful about adding reverb to your base drum. Too much reverb will make your beat sound muddy. In fact, this applies to all instruments of your mix. A nice little reverb on your base drum is a good thing, though. It’s a great tool to make your base drum sound more connected to the rest of your beat and to make it feel more natural. A dry, reverb-less base drum isn’t a bad thing in and of itself, either. For example, hip hop often uses a more detached base drum. It makes the base drum sound punchier. Playing around with reverb on different drum elements can even make the beat groovier. You might want to try adding reverb on the snare, but not on the base drum, or vice versa. Or you can apply different reverbs on different drum elements.
One last thing: Every base drum is different. Consider the numbers as a point of reference, but always let your ears decide. Do what YOU like.