In our latest technique of the week, Erin Barra takes a look at sub frequencies; a tough thing to control if you don’t understand a few basic things about them…
First things first, low frequencies carry a lot of energy and have to have a high amplitude for them to be heard very well relative to other elements in a mix. Think about when you’re in a club; high pitched sounds are easy to hear and cut right through a mix without any effort, but when you’re hearing sub frequencies well your body is usually shaking. The lower you go in the frequency spectrum, the higher amount of amplitude (loudness) is required for a more balanced mix.
When you have loud frequencies down low, you leave very little headroom for the rest of your mix and it can be difficult to wrestle with the frequency spectrum in that situation. Sub basses and 808’s are usually made from Sine waves, which only output signal at a fundamental frequency and contain none of the upper harmonics like a Square wave would. This lack of upper harmonics is a big part of why subs can be harder to hear.
Most people are listening on low-quality headphones or speakers which don’t have very good low frequency response, so those people aren’t hearing the entire range of frequencies anyway.
In order to make sure that people can hear your sub frequencies on whatever playback system they happen to have, the key is to create representation in the upper harmonics. Here’s two specific ways to do it:
1: Layer your Sine wave with a Square wave – copy the MIDI sequence, drop in an instrument outputting a square wave and mix it in so it’s adding that extra oomph without taking away from the phatter bottom of the Sub.
2: Overdrive your Sub Bass using the Drive knob on whatever native Saturator is in your DAW. Through Saturation you’re clipping the signal which adds harmonic distortion and in the case of a Saturator you’re adding ‘vintage warmth’ since it’s a Tape emulation. You could also do this with an Overdrive or Distortion plug in or hardware pedal.
By doing either of these you’ll create more texture above the fundamental frequency as well as be able to pull down the fader on your sub bass or kick track, giving your overall mix more headroom.