How do I add sub-bass easily to my tracks? I have a nice core ‘bass’ tonal synth but it lacks the low-frequency weight I’m looking for.
Antonio Sagese, via Facebook
SOS contributor Rob Talbott replies: In any computer-based tracks where you already have the MIDI information for the other parts, there are two core ways to go about this. The simplest would be to add a dedicated sub-synth channel, with your plug-in synth of choice set to output a pure sine wave — usually with infinite sustain but zero release, so that it immediately plays at full volume and just as quickly stops upon triggering/release, unless a longer release is required dynamically — and then copy the MIDI part for your bass track onto that track. You’ll probably need to transpose the notes to the correct octave or to set your sub-synth’s ocillator pitch internally, to make sure that it sounds in the octave below the original bass line.
However, this simple approach can lose some of the articulation of the original synth pattern, so I often find a second method to be better in many ways. If the soft synth you used for your main bass sound has the ability to generate a simple sine wave, create another instance of that synth on a new channel with the same patch, and then change its settings so that it is outputting a basic sine wave, as in the previous method — but don’t touch settings such as envelope attack or release, or portamento. This way, you’ll have a clean sine-wave sub-bass channel, but with dynamic characteristics identical to those of your original bass patch, so the two should layer seamlessly.
Where you don’t have the original MIDI parts and need to recreate them to add sub-bass, it can be difficult to hear the low notes accurately. A good tip is to play or draw in the notes a few octaves higher up, so that you can hear the notes more clearly, and then pitch them back down to the octave that gives you the nice warm sub-bass tone you’re looking for. Sub-bass shouldn’t really need any processing, as a straight sine wave creates nice, round bass, but sometimes driving it gently with a tube distortion plug-in can add some harmonics that fill a gap between the sub-bass and the more tonal elements of your existing bass. It’s very much a case of trial and error here, but do use your ears and a decent monitoring setup to make sure it sounds good.