Bass enhancement by Joe London (PRTCL)
What is bass enhancement?
Bass enhancement is a technique whereby a plugin like rBass, MaxxBass or Bass XL boosts and saturates a part of the low frequency content of a track, in order to create a more powerful and well-defined low end. Usually this happens in parallel, meaning that the boosted low end frequency content is added to the original signal. Some bass enhancement plugins focus a little more on creating new harmonic content, others a little more on creating a defined low end boost. Bass enhancers do not generate new frequencies below the frequency area that is enhanced, like a sub generator plugin would. They do, however, create new harmonics above the target frequency area that enhance the perception of the existing frequency content. These harmonics are always related to the track’s frequencies content (as opposed to adding low end frequencies with a sub generator) and can therefore be used on both rhythmic as well as melodic mix elements. Both the low frequency boost as well as the added harmonics can help your mix sound powerful, consistent and controlled in the low end, in a way that isn’t as easy to mimic with just EQ and compression.
What is technically happening in plugins like the Waves rBass, MaxxBass or the denise Bass XL?
When you apply subtle saturation to an isolated frequency area in the low end, additional harmonics are generated that are related to the existing audio. This essentially means that high frequency content is added, making the isolated frequency area sound more clear and defined, as well as more controlled dynamically. Mixing the result in with your original track, and boosting the volume, helps boost the low end in an exciting way. It’s a very underrated tool which helps make your mix sound fat, very quickly.
- The source signal is copied, and this copy is low pass filtered at frequency X (50 hz, for example) to end up with just a piece of the low end.
- The copy is then saturated to create new harmonics above frequency X.
- The copy is then high pass filtered at frequency X, to try to remove the original low copy, and just keep the added harmonics. (Note that depending on the steepness of the filters used, a part of the original frequency content will be preserved. This is the nature of the filtering used, which acts as a slope and not like a brickwall. So the frequencies below the designated frequency don’t just drop off, they’re gradually reduced in volume).
- The harmonic content is then low pass filtered, a certain amount of octaves above frequency X. Every octave (2 times the frequency) preserves 1 harmonic.
- The added harmonic content is then mixed back in with the original source signal.
This is very different to a sub generator like the Refuse Software which adds frequencies below the the fundamental.
What practical uses does it have?
- Boosting kick drums in the sub low.
- Adding a more resonant low frequency to a kick drum.
- Adding a specific low end coloration to a drum or percussion part or beat (or full mix).
- Warming up a bass or low synth or low guitar. Even on vocals it could enhance warmth.
- Adding subtle grit to low end instruments.
How do you decide when to use bass enhancement?
If you miss low end or warmth, and traditional EQ or (multiband) compression doesn’t seem to be effective, or if you do have low end but it is unstable. These plugins can bring back a stable and present low end with or without the use of compression.
Pro tips for bass enhancement – with Enrico Tiberi (nrec).
1. Enhance a bassline
Bass enhancers work great on bass, as the name hints at! So apply a plugin, boost the very low frequencies (around 80Hz) and drive it pretty high, so it gently smooths out the pumping from the sidechain. This is really useful if you have a thin sounding bassline that needs some more warmth and some extra sub frequencies.
2. Boost a kick drum in the sub
Apply bass enhancer directly to your kick bus (or individual channel) and boost around 50hz. Trying to boost a little of that sub frequency and some of its upper harmonics gives it both boominess and body. If the plugin has a position dial, dial in some pre-delay (short, about 1 or 2ms) to help keep the low frequencies really tight. A position knob is really useful here, as it avoids phase clashes with the original signal.
3. Add warmth to a synth
Bass enhancers can generally enhance frequencies up to about 300Hz, so using them to add warmth to instruments is also very useful if your original sound is quite thin. The frequency we’re trying to enhance here is around 100 – 200Hz, which helps the synth have more of an impact on the listener, especially in a club setting.
4. Boost a drum bus in the low frequencies
A bass enhancer can be used to enhance a full bus with more than one instrument, too. With this channel, I wanted to target the kick and the lower resonance of the toms, so set the frequency dial to around 70Hz to really feel these drums in your chest.