Sub Bass — The Dark Art

Mixing Bass & Why You Might be a Better Mixer than You Think

The Dark Art of Mixing Bass

Bass is the single most difficult thing for a producer to get right in a track. How do I know? Because it’s the area that usually needs most attention when I receive a track for mastering. The bass frequency range is crucial to giving a track its foundation: too much and it sounds clogged-up and lacking in the top / mid end; too little and it feels hollow with less drive and forward movement than intended. So why is it so hard to get right and what can you do about it? Here are the two most common causes of not-so-hot bass mixing, and their solutions:

1 —Monitoring

Did it ever cross your mind when battling to mix that soft-synth bass, that it was slightly odd some notes were ringing louder than others? You’d think every note coming out of a computer was at a similar sound pressure level really wouldn’t you? Well, the fact is, they probably are. When you’re trying to mix an unbalanced frequency range, you’re always going to be fighting a losing battle. But the good news is, overcoming the cause of this problem requires a blatantly simple first step, so I’ll get it out of the way (and because you might already suspect this): your monitors aren’t up to scratch. It’s an old adage, but you get what you pay for and it’s worth noting that the more you pay, the smaller the increments in quality get, but they are increments.

Ups and downs and other undulations

So what’s going on with the different volumes of notes then? You know how some hi-fi systems have that super-bass-boost-button that makes the room shake? Well, it’s kind of the same thing but on a subtler level. If a monitor’s frequency response has a volume bump at 80Hz, any notes around E2 on a bass guitar are going to sound louder than they actually are. So naturally, being a good mixer and producer, you compensate for this bump by bringing down that note in volume a notch using automation, or in the case of a soft-synth, altering the velocity. So you can see what’s going to happen if you then play that track on a different system through different speakers. Yep, that E2 note is now going to be too quiet because the new speaker system doesn’t have a bump at 80Hz. And every speaker system has its own bumps and dips, only the better ones have fewer and less drastic ones. So that soft-synth you’ve been struggling to mix, is grinding out bass notes at a correct and even level, they’re just not being communicated correctly by your monitors.

Dip in the Bass Frequency Response Graph

Flat Bass Frequency Response Graph

1a) You can clearly see a dip at 75Hz
1b) A flatter curve across the bass end is the ultimate aim

 
So some monitors are better than others, and the better the monitor, the more accurate the sound. And by accurate, I mean as uncoloured as possible. This is a pretty easy first fix to apply, so long as you have some cash to spare. Generally, the more you spend (and I’m talking about spending on purpose designed studio monitors here, not hi-fi speakers), the less coloured the sound will be, which translates to the flatter the frequency response will be. And a flat response is the holy grail for our purposes because it enables us to hear the bass end as it really is, not as the speakers are making it sound.

Bish bass dosh

So spend as much as you can reasonably afford on your monitors. And then remember to go easy on yourself: understand that your previously cheap monitoring was making you sound like a worse mixer than you actually are. It’s a reassuring thought that in compensating for the monitors’ deficiencies, you are actually practising the art of great mixing because you’re identifying there’s a problem with the mix and fixing it. It’s just that you’re fixing a problem that isn’t to do with your mix at all. It’s like painting a picture of a green valley on a cheap computer screen that displays the colour green lighter and more washed out than it actually is (and lighter than how say, a Mac retina screen would). To compensate, you make the grass a couple of shades darker. It looks fine on your screen, but on your friend’s iMac, it’s going to look way too dark.

Acoustic Treatment Bass Trap

2 —Your Room

Not quite so simple to fix, is the second most crucial aspect to mixing bass successfully: the shape and size of your room. Most DIY producers are working out of makeshift studios, bedrooms / backrooms / garages etc. and so the dimensions of the room are set. But why-on-earth do the dimensions matter and what can you do about them anyway? Essentially, the waveforms emanating from your monitors aren’t travelling straight into your ear. They’re bouncing off the walls, ceiling, floor, desk surfaces etc. and are arriving at your ears at different times (because some will have travelled further before being reflected back).

The length of the room’s walls and its height have mathematical relationships with the length of the waveforms. This creates a situation where waveforms are bouncing off surfaces and meeting themselves at different points in space resulting in their waveforms crossing. And when two identical waveforms don’t line-up, they make each other quieter or louder on a sliding scale to the point where they can cancel each other out entirely. This complete cancellation happens when the peak of the waveform of one version of the sound, lines up perfectly with the trough of the same waveform of the other version of the sound. Which seems a bizarre concept at first, but once you understand this phenomenon occurs, you can arm yourself to combat it. Conversely, if a waveform reflects off a surface and its returning peak matches its outgoing peak, the amplitude increases and you have a note that is louder in your studio than it would be anywhere else.

Sine Waves

The long arm of the bass-wave

Bass waves are particularly problematic because their waveforms are so long. For example, a bass note at 50Hz is roughly 6.8 metres long, so stopping a 6.8m waveform from doing anything undesirable in the studio requires some heavy-handed tactics. Basically, serious bass trapping (ie. foam or acoustic panels as absorbents). The point of bass trapping is to turn some of the bass energy emanating from the speakers into heat, by causing friction. This reduces the peaks of the waveforms and raises the troughs, essentially lowering the waveform in amplitude.

So start by putting traps in the corners of your studio because bass-waves tend to build up along hard edges, and of course in corners you have two hard edges. And where the ceiling and floor meet the walls, you have three. Reducing the amount of bass-wave energy in the room mitigates the piling up or cancelling-out of peaks and troughs, resulting in a far more accurate room to judge your bass mix in. Treating the room with acoustic bass absorbers isn’t the most glamorous or exciting studio item to spend your money on, but it will result in you having tracks with a much better mixed bass-end. So ultimately you’ll have tracks that reflect your actual skill at mixing and you can start bolstering your mixing-confidence again.

Great Bass in Your Space

Getting your monitoring right, and your room right are the two most effective steps you can take toward improving the bass response in your mixes. Without them, it’s like pushing a shopping trolley with a bad wheel — you’re always going to be heading for somewhere you weren’t intending, despite your best efforts. You may prefer to spend your money on a new guitar, or synth or whatever other fancy glamorous bit of kit you’ve got your eye on. But the truth is, you’ll make your life infinitely easier as a mixer, if you put the right monitoring into the right environment and create a sympathetic space within which to listen to those shiny bits of kit. Because after all, they aren’t going to sound as good as they should, if you can’t hear them properly.

Happiness is a warm sub — MS

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