Drums are a critical element of any mix. You can have a great vocal, with a great instrumental, but without the drums it’ll lose its drive and punch. If you are writing/producing a sweeping ballad then maybe you don’t need to worry. Sometimes you want the listener swept away by the flow of instruments surrounding the vocal and the drums need be minimal, if they are there at all. For everything else, you’ll want those drums sitting cleanly in the mix.
While the drums are usually the first instruments I mix, I will also revisit the drums about 3/4 of the way through the project. I will listen carefully both with the entire mix and when solo’d to double check that the drums are tight and still have the energy to propel the mix forward.
Sometimes, the drums won’t sound right in the full mix, and possibly something has gone awry and they don’t sound right solo’d anymore either. If the drums sound off then here are a few good starting points to fix it up:
Each instrument (kick, snare, toms, …) needs to have the right attack and release times to have impact and ‘hit’ at the right time.
Look at your compressor attack/release — is it smacking down the attack portion of your snare hit? Is the release too slow and therefore you can’t hear the tail of the snare hit?
Try a transient shaper to give that initial hit more impact.
Be careful when playing with the dynamics because instruments with a strong attack can trigger (pump) your bus and/or mastering compressor. Compress judiciously and try a limiter to keep the dynamic range of the instrument contained.
For kicks, the tail (usually sub-bass) portion should have the right release time. You don’t want a kick too boomy (unless it’s hip hop) nor do you want a kick that’s so short it lacks punch.
Tuning: Your kick and snare have a fundamental frequency. Tune it so that it’s in the same key as your song. The kick is particularly important because an out of tune kick will interact with your bass in ways that will not sound pleasant.
I find a lot of reverb plug-ins sound terrible for drums. Snares in particular can sound unnatural, so pick a reverb that sounds ‘authentic’ and does not distract from the drum hits. I tend to have more luck with convolution reverbs than other algorithms. Some reverbs can sound good but make the drums sound muddy or unclear. Sometimes I will put a compressor on the drum reverb, side chained back to the drum track. When the drums hit, the reverb will quiet down until the drum hit is complete, at which time the reverb goes back to normal volume. This ensures that the drums have the space in the mix needed to hit the listener cleanly.
To give your drums extra punch, try double bussing or running your drums through a tape emulation plug-in. There are also plenty of saturation plug-ins to use as well. Use judiciously. You want enough saturation to make your drums sound larger without sounding unnatural or distorted. I find that some saturation plug-ins can make the low end sound great but have an unpleasing effect on the kick smack. Make sure you’re thinking about the whole kick and not just how the lows hit you in the gut.
Mono vs stereo
My starting point is almost always having the drums in mono (before reverb). If it’s a busy mix, having drums panned across the stereo field can add clutter and make the overall drum section sound weaker. Having the drums (or the key elements thereof) in mono will free up room in your mix for those other musical elements to shine.
The above list is by no means exhaustive but it’s a good starting point for working through problems with your drum track. It’s a mix of science and art so there is never 1 recipe to make it all work. Dial away.