Mixing the Low-End: How to Get that Thick & Punchy Layer

If there’s one thing that sets an experienced studio engineer apart from a novice, it’s how well they mix the lower-frequency instruments of a track. Here, I’m referring to the kick drum, the bass, the lower sonic regions of the guitars, synths, and keyboards – since it’s all of this that makes up the low-end, and it’s these lower frequencies that are harder to mix than any other part of the frequency spectrum. But why? And how do you get that thick and full, punchy layer that’s going to sound awesome on any set of speakers you put it through? Read on to find out.

Arrangement

The reason that high-end productions sound so good is that the producer already starts thinking about how the frequency spectrum is distributed while they’re putting the arrangement together. The lower end of the frequency spectrum can fill up pretty quickly, so to ensure that it remains clear and punchy, it’s best not to let it get too complex. This is why you’ll rarely hear a bassist play chords, and why bass synthesizers are usually monophonic. A good starting point is to make sure that only two bass-heavy instruments ever play at the same time – like a kick drum and bass guitar. When it comes to the rest, you can make smart choices when deciding which instruments are used and the style in which they’re played so that room is always kept free in the low end. For example, you can ask the keyboard player to leave out their left-hand part, leaving out their bass notes to give the bassist more room. Also, have an awareness of the instruments that you’re dealing with. So, if you have a nice, woolly sounding Rhodes piano riff in the track, be aware that it tends to fill out the lower-mids, so you might want to ask the guitarist to play their chords in a higher register. Little shifts and tweaks like this will really make all the difference, even before the mixing process has even started.

Monitoring

You can’t mix what you can’t hear, and lower frequencies are actually very difficult to accurately reproduce. This will have a lot to do with the quality and range of your speakers, but may also have something to do with the room you’re mixing in. Try playing a reference note at 60Hz and walk around the room. In some parts of the room, the note might be barely audible while in others, it might suddenly sound much louder. Even if you have a great set of speakers, this is only half the battle. It’s just as important to position your speakers in the perfect spot so they’re able to deliver the full frequency range without too many peaks and dips – so that they sound as neutral as possible. Further than that, you can also improve the acoustics of the room by mounting a few absorbers, bass traps, and diffusers on the walls and ceiling. As the cherry on top, you could even kit yourself out with some good calibration software, like Sonarworks Reference. Bear in mind that, in smaller rooms, it will always be harder to get it right, even if you’ve done all of the above. Finally, a set of headphones can certainly give you a good ‘second opinion’ and you can read more about the role they can play in mixing in this blog. I also recommend having a read of this blog about using subwoofers in the studio.

Hacking, Sawing, Filing Down & Polishing Up

As the mixing engineer, you don’t always have a say over the arrangement and instrument choices of a production. But, what you can do, is create room for the bass instruments using equalizers, gates, and compressors. With vocals, you can easily filter out everything under the 100Hz point using a high-pass filter, and with something like a shaker, you can comfortably set a high pass filter at the 500Hz point to get rid of the all the lows that it doesn’t need.

If you have a kick with a long reverb tail to it, then this can get in the way of the bass guitar or synth. Using a gate or expander, you can shorten the sustain of the kick to tighten it up. Since the kick is now playing ‘shorter notes’, you only have to make room for it ‘temporarily’ and you can do this by using a compressor or multi-band compressor with a side-chain function. You can then (for example) put the bass guitar through it, or any other instrument that the kick might be getting in the way of, then select the kick drum as the side-chain input and put the attack and release speeds at a really high level. Now, every time the kick hits, the compressor will push the bass guitar down and out of the way.

Effects

When mixing a track, you’re not only busy filtering things out, but you also get to add some more fun stuff like reverb and delay. But if you’re not careful, these kinds of effects can quickly turn your low-end into thick mud. Luckily, most delay effects will have a built-in high-pass filter that you can always use. Otherwise, you can always send the delay through a separate filter or equalizer. When it comes to reverb, besides filters and shelves, you’re also often able to control the decay time of the lower frequencies separately, so you can get a nice and full sound, but the low-end reverb dies off a little quicker.