Sub bass is part and parcel of modern dance and pop music, whether serving as the main bassline on its own or rolling along underneath a higher bass sound, and there are numerous technicalities to consider if you want yours to sound on point. Here are eight tips to get you on the right track.

1. Work with the kick drum

Synthesised kick drums often extend down into the sub bass range, which can cause them to clash with your actual sub line. To alleviate or avoid this mix-damaging issue, either high-pass filter the kick to trim off the offending frequencies, or duck the sub every time the kick drum hits, using a compressor with an external sidechain input, a dedicated volume ducking plugin or a dynamic EQ. Alternatively, consider whether or not you actually need a sub-heavy kick drum at all – if your sub bass has that end of the frequency spectrum well covered, it could be worth substituting the kick for a shorter, ‘clickier’ one.

2. Layer up for small speakers

If your bassline comprises nothing but a sub, it’ll be completely lost on the smaller playback systems so prevalent today: laptops and iPads, portable bluetooth speakers, etc. While, of course, there’s no escaping the laws of physics, you can imply the presence of the missing sub by layering a ‘regular’ bass instrument over the top, an octave up, mixed in at whatever volume feels effective. This will also bring clarity and presence to the low end on larger systems, and is in fact the way sub bass is often deployed in the first place: as a reinforcement layer under a higher line. Watch out for phase issues when doing this, though – the phase invert switch is your friend.

3. Hip to be square

For that classic smooth, deep sound – particularly under a higher layer, as described above – a sine wave may well be your first port of call for sub bass synthesis. However, a square wave can be equally if not more effective, depending on the context of the track, as, to a lesser extent, can a triangle. As well as just sounding usefully different right off the bat, unlike a sine, you can filter square and triangle waveforms for harmonic interest, which, also helps them to come across better on smaller playback systems. There’s nothing stopping you combining a sine with one of its angular siblings, either, for the best of both low-frequency worlds, but, again, listen out for phase problems.

4. Distortion never fails

Another proven tactic for bringing bite and presence to any sub bass line (and, once again, helping it out on those smaller speakers) is to treat it to a healthy dose of analogue distortion. The harmonics introduced by preamp, tape, amp sim, waveshaping and other saturation plugins can work wonders when it comes to toughening up and lifting a sub line in the mix, or transforming it entirely for DnB-style impact and character. If your distortion plugin of choice compromises the body and heft of your sub in the process of enriching its higher frequencies, play with the dry/wet mix to bring back as much of the unprocessed signal as required.

5. Keep it mono

Unlike regular basslines, which are receptive to chorusing, widening and other stereo-ising processes, sub bass should, as a rule, be resolutely mono. Although the vinyl cutting issues of the past, caused by overly wide low frequencies, are no longer particularly relevant, messing with the central focus of the sub plays havoc with its ability to be felt and clearly heard, and can really throw the whole mix off balance. Don’t do it, kids.

6. Filtering and EQ

With the frequencies of your sub bass line potentially reaching all the way down to the very lowest limits of human hearing, running it through a high-pass filter set to 30Hz or thereabouts is always a good idea – as, indeed, it is at higher cutoff frequencies with any other low-end-occupying instrumentation, from electric bass, guitar and synths to keys and even vocals. Discarding the inaudible rumblings going on below that point prevents them from unnecessarily taking up valuable headroom, giving you space to turn the part up if required, and generally decluttering the mix.

7. Get a plugin to do it for you

Any analogue synth can be pressed into service for sub bass, but if you’re serious about your subs, there are numerous plugin instruments and effects available dedicated to synthesising them from scratch, or generating them automatically, based on the tracked pitch of an input audio signal. In the first category, every producer should have a Roland TR-808 emulation in their arsenal for that legendary extensible kick drum sound (D16 Nepheton or Roland’s own TR-808 plugin, for example), but the purpose-built likes of Future Audio SubLab and Rob Papen SubBoomBass 2 expand greatly on that formula, with comprehensive layering, distortion and modulation built in. For underpinning existing basslines with pitch tracking sub layers, look no further than Waves Submarine, Boom Library Enforcer or reFUSE Lowender.

8. Make sure your monitoring is up to the task

It goes without saying that if you can’t hear the sub bass in your productions, you’re going to have trouble mixing it accurately. Obviously, a dedicated subwoofer unit is the ideal solution for this, but if you don’t have the space or money to accommodate such a box, and your monitor speakers bottom out at 40Hz, as many do, use a decent set of headphones (with a frequency response down to 20Hz) to check your sub bass at regular intervals, and run a spectrum analyser plugin on the channel to ensure that you can at least see what you can’t hear. Also, be sure to test your mix on a system fully capable of representing the sub before you commit to it.

Share your sub bass-related thoughts in the comments.