Learn how to create, mix, and layer sub bass in this guide. Included is a FREE Sub Bass Instrument Rack for Ableton Live.
Sub Bass Explained
The audio spectrum is an audible frequency range that spans from 20Hz to 20,000Hz. The full range can also be divided into seven different frequency bands: Sub, Bass, Low Mids, Mids, Upper Mids, Presence, and Brilliance. Sub bass sounds typically exist in the sub frequency band that spans from approximately 60Hz down to 20Hz. More often, sub bass will inhabit your mix in the 40Hz to 60Hz range. You can try to go lower than 40Hz, but most speakers won’t be able to accurately articulate frequencies that low. In addition, human hearing is not very sensitive to frequencies under 20Hz, so sounds in this range tend to be felt more than heard which provides a sense of power. Sub sounds that extend below 20Hz are called infrasound. Most sound systems often feature subwoofer loudspeakers that are dedicated solely to amplifying sounds in the sub bass range.
Creating Sub Bass
The most common approach to creating sub bass is using a basic sine wave an octave or two below your fundamental bass notes. A sine wave will give you a pure tone without all the harsh higher harmonics that saw or square waves produce. A triangle wave produces a subtle amount of higher harmonics and will work better on small laptop speakers or earbuds. You can also layer waveforms to create a thicker and more powerful sound. Sine wave subs are single harmonics that are very clean-sounding, but don’t necessarily push the low-end to its full potential. You can achieve more weighty sub frequencies by subtly mixing in a square wave with a sine wave to produce a more heavy sound for example. Additionally, if you are using an FM synthesizer, you can add another sine wave to modulate the first oscillator to create some extra punch.
Mixing Sub Bass
Treating your sub bass sounds is also essential to achieving a solid low end. You can get more out of your sub bass with some simple mixing techniques that will help control and enhance your sub frequencies. First, it’s important that you are using decent speakers or headphones to hear your sub bass adequately.
Sub bass can be overpowering and can quickly use up a lot of headroom making it hard for other sounds to cut through the mix. It’s extremely important to control your low frequencies to achieve clarity in the overall mix. Below are some typical sub bass treatment moves that will help shape your speaker rumblers.
- EQing is a crucial step in shaping your sub bass. It’s highly recommended to cut higher frequencies above 100Hz to 200Hz to create space for other sounds in your mix. The goal is to focus on low frequencies and remove any high frequencies that may clutter the mix. In addition, you may want to remove any infrasound frequencies that the human ear cannot hear which uses up an unnecessary amount of headroom as well. An EQ roll off below 40Hz can help achieve clarity and punch. In most cases, removing ultra low frequencies will actually make your sub bass sound louder. Also, it’s important to be aware of any additional EQ moves. Boosting the sub bass range can make the sound overly powerful and quickly use up your available headroom, whereas cutting too much of the sub bass range will weaken and thin out the sound. It also crucial that you remove any low frequencies on all your other sounds in the mix to make room for your sub bass.
- Applying saturation is another common treatment that can beef up your low end by introducing additional harmonics. It is often recommended to apply saturation before you cut frequencies with the EQ to ensure you remove any unnecessary high frequencies that your saturation/distortion plugin creates.
- Compression is another move that is essential for controlling your sub bass and giving your sound some additional punch. Medium-fast attack times and medium-fast release times will ensure your sub bass is smooth and consistent while controlling any spikes that may cause clipping. There are no magic settings, so it’s crucial that you use your ears and judgment to dial in the right amount of compression that suits your needs. Additionally, a second compressor setup to sidechain from your kick or another sidechain source is also highly recommended to quickly attenuate the volume so your kick can cut through the mix. Both the kick and sub bass will occupy some of the same low frequencies, so it’s important that you make space for these frequencies to achieve punch, presence, and clarity.
- Lastly, it is extremely important to ensure your sub bass is mono for several reasons. A mono signal will have more punch and presence than a signal that is spread across the stereo field. Also, most club speakers are mono, so you will lose a lot of your low-end power making your track sound weak when played alongside commercial masters. It’s also wise to check your mix with a frequency analyzer and a stereo analyzer to visually inspect your sub bass.
Sub Bass Layering
Keeping the sub bass separate from the other bass parts is a common technique used to achieving a powerful and clean low end. Simply, copy the MIDI notes or record the same notes from your other bass parts to create a separate sub bass track. However, it’s important to be aware of the envelope settings on your sub bass track. If the envelopes don’t closely match the other bass parts, you may hear that two sounds are off and that they sound awkward. You may also hear unwanted clicks or pops. One approach to ensure your envelopes match is to duplicate your bass part to create another instance of that same bass sound on a new channel with the same patch settings, and then change the oscillators to a basic sine wave. This way you will have a clean sub bass with the same envelopes and dynamic characteristics that layers seamlessly. Finally, make sure you remove any low frequencies from the main bass part that overlap the sub bass to ensure clarity and presence.
Ableton Live Sub Bass Instrument
For any Ableton Live users out there, we put together a simple Sub Bass Instrument Rack that generates low frequencies with Live’s Operator Instrument along with some extra processing effects to enhance your low-end boomers.
- Pitch: Transposes your MIDI notes up or down as low as -36 st.
- Knock: Modulates Oscillator A to introduce a short transient boost at the note onset to help the sub bass cut through the mix.
- Over Tones: Introduces a square wave that runs parallel with the sine wave generated by Oscillator A.
- Drive: Applies saturation to introduce additional harmonics.
- High Cut: Sets the high-frequency cutoff point. The range spans from 60Hz to 250Hz.
- Low Boost: Amplifies or attenuates the low frequencies below 100Hz.
- Comp Thresh: Adjusts the Compressor’s Threshold control.
- Level: Increases the Limiter's Gain control to boost the overall level and protect your speakers from any sudden surges.
