We hope that, in this article you come to a better understanding how to compress kick drum so you will be prepare with knowing what to do the next time you sit down to mix them.
In short, in order to achieve better results, you may consider cleaning your drum multi-tracks and fixing issues with phase alignment if such occur. Applying some subtle EQing might also be a great idea, as well as putting your kick drum mics through a common bus.
When it comes to compression, use a significantly fast attack and auto-release if possible. Put your threshold so you would get somewhere around 6 dB of gain reduction and use the ratio of 5:1 as a starting point and increase it if you want a more aggressive compression.
Now, let’s take a deeper look.
Before the compression
A compressor is a device or a piece of software that reduces the dynamic range of any incoming signal. Depending on particular settings, it can help to bring up the sustain but also could emphasize the initial transients, which is exactly what we wanted to do when it comes to a kick drum.
But before we even begin to apply the compression, there’re a few minor inconveniences that could get in our way and prevent us from compressing our kick drum perfectly.
So, firstly, we have to clean up our multitrack recordings, address issues with the phase, if they occur, maybe apply some EQ, and bus together some individual tracks.
Clean up first
This step is rather optional but still might be necessary if your initial recording isn’t particularly perfect.
Any timing and stylistic mistakes may distract the listener from the overall atmosphere of the track unless it was a conscious artistic choice of the performer and the playing was intended to be imperfect. But if you’re going for a very polished sound, it’s better to quantize the notes or, if it doesn’t seem possible, to rerecord the drum session altogether.
Cutting off the silence is also a pretty useful idea, considering that removing any part of the track that is not musically relevant will make the track sound a lot cleaner, especially if an aggressive compression would be applied.
Phase alignment
Unless you’re using a production-ready virtual instrument, there’ll be some issues with phase alignment. Most of the time, they wouldn’t need to be addressed, but if you’re going for a very polished production, some tweaking might be required.
While recording drums, we are usually dealing with multiple microphone positions, which means that most of the microphones would pick up signals that they weren’t intended to. And since microphones are placed within some distance from each other, the signal picked up by different microphones will be delayed and some phase cancellation will occur, thus, making the said signal sound less pronounced. In order to fix this, you can align tracks manually or use a dedicated plugin which there are plenty of.
Bus the tracks
If you use multiple microphones to record your kick drum, it might be a good idea to bus them together. Making them go through a common signal path will make it much easier to mix them later and will relieve your CPU since you wouldn’t have to use separate plugins for each of the tracks. Usually, it’s better to organize your session before you start the recording or even save it to the template, which isn’t really necessary but, nevertheless, can make your workflow significantly faster and your audio engineering experience way smoother. And while you are at it, you may as well balance the tracks and gain stage them so they would sit better in the mix.
EQ if needed
Using an equalizer before the compression or after is a matter of personal choice and experience. Compressors tend to change the tonal content of the track, so EQing it afterward can help you to bring back the tonal balance, but we recommend using EQ beforehand, so the compressor would work more accurately.
Usually, kick drums have a lot of content in the low and mid-range and very little in a high-frequency range, which means that the compressor would react to the low-range without affecting the high-frequencies. And since most transient information is stored within middle and high-frequency range, it’s better to reduce some low-frequency contents in order for a compressor to affect the full spectrum.
Of course, you can always use a multiband compressor that can affect certain frequencies leaving the others untouched, but some simple mid-range scoop with an equalizer should do the trick just fine.
How to compress a kick drum
When it comes to compressing the kick drum, usually, our goal is to bring up those initial transients so it would sound a lot snappier and, thus, more pronounced in the overall mix. If you’d solo the drum tracks, you’ll most certainly feel that kick drum doesn’t need any compression, but when you start to bringing back other instruments, the kick drum, most likely, will sound less articulated even to the point when it’ll be completely lost in the mix. So it’s safe to say that we use the compression on a kick drum in order to bring back its initial energy or at least emphasize it if the mix isn’t too dense.
What compressor to use
Any compressor is capable of successfully compressing the kick drum, even a stock one that comes with your DAW will do the job just fine. But when it comes to audio production, it’s always better to take a step further if it’s possible in a given situation. Stock plugins tend to sound very clean in order to be versatile and as universal as possible, but in most cases, this isn’t exactly what we’re looking for. Modern DAWs and any digital audio, in general, tend to be almost surgically transparent, which instinctively pushes us towards adding more coloration and some non-linear behavior to our tracks. That’s why top audio engineers prefer to use compressors that emulate some of the best vintage gear, which is something that you might also want to try for yourself.
Attack
Since we’re talking about emphasizing the transients specifically, the attack should be considered the most important setting of our compressor. On a kick drum, you want it to be very fast, but be careful not to overdo it because there’s a risk of making your kick drum sound unnaturally squashed. Placing your attack knob somewhere around 4-10 ms should do the job just fine, but there’s a little trick that might help you. Dial in the highest ratio possible and turn the threshold all the way down. After that, put the attack to 0 ms and slowly move it to the right until you can hear something satisfactory, after that, put the threshold and ratio to more manageable levels.
Release
If your compressor is capable of auto-release, this is a setting that you should definitely leave turned on. When it comes to compressing a kick drum, you have to make sure that it catches as many transients as possible, so auto-release makes sure of that. If your compressor doesn’t have an auto-release function, you, unfortunately, will have to adjust it by ear, but not to worry, there’s also a trick that might help you. One minute contains 60 thousand milliseconds and if you divide that number by the BPM of your project, you’ll get the exact length of your quarter note in milliseconds. So if, for example, your kick drum has a straight 8-note pattern, divide that number further by 2 and you’ll get exact release settings in milliseconds.
Threshold
Threshold is a setting that tells your compressor at which volume of an incoming signal it should start to work. If you want your compression to be more subtle and you’d be happy with just brushing off some peaks, leave it at its highest position. But if you want more aggressive compression, place it further down in such a manner that it would give you somewhere around 6 dB of gain reduction. You can go even higher than that, but usually, it’s completely unnecessary and might be even somewhat harmful to the perception of a drum track.
Ratio
Ratio shows how much actual compression would happen. If you set your ratio to 3:1, this would mean that for every 3 dB of the incoming signal, there will be a 1 dB of gain reduction. Sounds a bit complicated, but what it actually means is how subtle or obvious your compression will sound. Lower ratios will give you a more natural sound and almost undetectable compression, higher ratios will give you a more aggressive and pronounced sound. For a kick drum, a good place to start is somewhere around 5:1 or even a bit higher, depending on the material and the style of playing.
Conclusion
Compression is what beginner audio engineers usually struggle a lot with. And no wonder – compression is a pretty tricky subject to grasp. It can be hard to hear with the untrained ear and very easy to mess up, considering how sensitive the controls usually are. Luckily it’s significantly easier to understand compression when it’s applied to drums.
