What You Need to Know About Processing Bass

By Donald Dinsmore

Few things are as satisfying or as exciting as loud bass.  Earth shaking bass is a cornerstone of modern dance music and hip hop.  If you want your tunes to measure up to professional releases you need to take care of the low end.  Thankfully a powerful low end can be achieved without too much work.  In this article we will run you through some of the ways the pros get their basses round, heavy and tight.

Select the right Sound

One of the most important parts of making bone rattling bass is to select the right sound from the beginning.  Ever heard the saying, "you can't polish a turd"?  What was bad before processing will still be bad after processing.  On the other hand, what was good before processing can be exceptional after processing.  What makes a sound the right one for a song is 1/10th objective and 9/10th subjective.  Does the genre of the song you're making call for something deep and smooth or aggressive and distorted?  If you have a rough idea of the sound you're trying to make you will be more productive than if you simply tweak knobs at random.  It is important to consider the other elements in your song as you make decisions about bass.  Does your song have a lot of low frequency pads and multiple leads?  If so you're tune might benefit from a deep, clean bass without too much high frequency content.  If you song has loads of space in the mid and high register you may opt to fill it with a harmonically rich bass line.  

Give you Kick and Bass Space

One classic area of concern for producers is how the kick drum and bass fit together in the mix.  Often these two elements are loud and fill the same frequency range.  This can lead to phasing, frequency masking or muddiness.  One effective strategy to deal with this problem is to separate the frequency range of your kick and bass.  This means if you have a deep sub heavy kick, your bass should sit at a slightly higher frequency.  If you have a high pitched kick you will likely have space for deep sub bass.  At the end of the day this means the fundamental frequencies of your kick and bass won't be sitting on top on one another.  Another good habit is to tune your kick (and all of your other drums for that matter) to the key of your song.  By tuning your kick you will reduce deconstructive interference between the kick and bass which will leave you with a tighter clean sounding mix.

Equalization

EQ is the foundation of any solid mix.  Conventional wisdom suggests it's more transparent to cut with EQ than to boost.  It's no different with bass, start by cleaning up the low end of your bass.  Set filter 1 on EQ Eight to high pass and cut everything below the fundamental frequency.  Do the same to your kick drum.  Next consider how the bass and kick are sitting together.  Imagine your kick hits at 98 Hz and the fundamental of your sub hits at 50 Hz. Make a narrow cut in the bass around 98 Hz to give room to you kick.  Another trick producers use to provide definition among the low frequency elements in their mix is to make narrow EQ cuts between 250 - 300 Hz.  Several instruments accumulate frequencies in this range: bass, kick, snare, pads, guitar, leads, vocal etc...  This frequency accumulation makes it difficult to distinguish overlapping mix elements from each other.  Producers often refer to frequency build up in this region as mud.  

BassVsKick

Compression

After EQ, compression is the next most important mixing tool used by producers.  Compression is often though of as a way to smooth dynamics and boost the gain of mix elements.  While this is true, when the sound source doesn't have much in the way of dynamics, like most synthesized bass, compressors are most often used to add punch and shape the tone of the signal.  Start with a fast attack time, medium release time and a ratio of 4:1.  Bring the threshold down until you get around 4-6 dB of gain reduction.  Adjust the release time so that the gain reduction recovers before the next note is triggered.  Altering the attack time will either add or remove emphasis from the beginning of the note.  A fast attack will clamp down and reduce the gain of start of the hit making the hit softer.  A slower attack will allow the initial loud part of the note to sneak through the compressor emphasizing the start of the note.  Often producers will add multiple stages of gentle compression instead of a single hard compressor.  This approach often delivers more transparent compression and may be preferred to obvious hard compression.

Compressor

Get your ducks in a row: SIDE CHAIN COMPRESSION

Another classic approach to addressing mix issues arising between the kick and the bass is sidechain compression, sometimes called ducking.  Do you know that dramatic pumping effect in French House?  That's sidechain compression.  When the kick hits the volume of the pad is reduced.  The volume of the pad recovers until the kick hits again causing yet another reduction of the pad's volume, which ultimately results in a rhythmic pumping effect.  Sidechain compression can be used to move your bass out of the way of your kick when they are playing at the same time.  The ducking of your bass when the kick hits can help achieve a cleaner mix and save headroom.  To set up side chain compression you need to override the normal function of the compressor.  In Ableton this can be done by clicking on the little arrow to the right of the compressor bypass button.  A new window will open on the left hand side of the compressor revealing a button that says 'Sidechain', click it.  In the drop down menu labelled 'Audio From' select the track containing your kick.  This will send the output of the kick track to the input of your compressor so when your song plays the volume of your kick drum will trigger the compressor to reduce the gain of your bass if the threshold is set low enough.  Set your attack as fast as you can without hearing clicking and adjust your release so the gain reduction recovers before the next kick hits.  A slower release time will cause a more pronounced and obvious effect while a fast release will result in a fast gain reduction that will be less apparent.  Release time is sort of tricky to dial in because it depends on the tempo of your track and the natural decay of the kick drum.  You can control the depth of the effect by playing with the threshold.  A high threshold will result in less gain reduction and a lower threshold will result in more gain reduction.  At the end of the day you can sidechain any track to any other track so be creative and mess around with it. 

Sidechain Compression

SUb Bass

For your tune to really perform well on a big sound system you need to have sub bass.  Sub bass can loosely be defined as anything below 90 Hz.  Sub frequencies are felt not heard.  The whole point of sub is to push air.  Before you reach for your EQ to apply a low shelf boost, try adding sub bass with your synth.  Most producers consider the harmonically pure sine wave the best choice to produce clean and powerful sub bass.  Some soft synths like Analog or Serum have dedicated sub oscillators that add a wave of your choosing an octave below the next lowest oscillator.  If your synth doesn't have a sub oscillator put your main bass synth in an instrument rack (CMD+G) and create a new chain.  Put the Pitch MIDI effect on the chain you just created followed by Operator.  Turn on operator A and set the wave to sine.  Now you have sub bass!  Just remember that because a sine wave is harmonically pure (one peak if you look at in Spectrum) chances are you won't notice much of an effect if you modulate the filter cutoff.  If you want your sub bass to move around with whatever modulation you put on your main bass try modulating the volume of the sub instead of the filter cutoff.  Some producers add harmonics to their sub with distortion so it will be audible on smaller sound system (think laptop speaker or headphones).  Adding plugins like Saturator or Dynamic Tube can having a pleasing warming and thickening effect on subs but be careful!  Too much distortion on a sub will kill the weight of the sub. 

Distortion and Stereo Effects

Applying effects to your bass can lead you into murky waters.  Producers use a host of effects on their basses to beef them up and spread them out.  Distortion plugins like Saturator, Dynamic Tube, Erosion and Overdrive can do wonders to thicken up basses and make them sound more aggressive.  Try adding these one by one and in combination with other distortion plugins.  Distortion adds harmonics.  For example if you take a sine wave and look at it in Spectrum you will see one harmonic (one spike).  If you add distortion to the same sine wave and look at it in Spectrum you will see a series of peaks that look something like a comb.  These additional peaks are harmonics and they add girth and body to the sound.  This can benefits your bass in a couple key ways.  One, your bass will sound more full due to the added harmonic content.  Two, you will gently control the dynamics of your bass (analogous to how a compressor controls dynamics) through a process known as soft clipping which will result in a higher RMS volume (average volume) without an increase in peak volume.

Pure Sine wave from Operator without Saturator and with Saturator.

Pure Sine wave from Operator without Saturator and with Saturator.

Other effects commonly used on basses are stereo effects like Chorus, Reverb, Delay or Flanger.  These effects can add interest and beautiful stereo width to your bass but you need to be careful.  Applying stereo width to frequencies below (200 - 300 Hz) will destroy the power of your bass.  When you work with bass it is often helpful to separate your sound into distinct frequency bands, low, mid and high.  This way you are able to add the benefit of stereo effects without applying them to low frequencies.  We made a little video that shows you how you can make a multiband frequency splitter with an Audio Effect Rack and Multiband Dynamics.  Check it out: 

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