The Frequency Spectrum for Electronic Musicians

"One of the most common requests of new producers who are struggling to get to grips with mixdowns is for some kind of 'guide' to the frequency spectrum. What should go where, and which are the problem areas to look out for."

We've seen a few of these around the internet, but mainly tailored to live and orchestral music. So here's our potted guide to what electronic musicians need to know when learning the ropes!

100Hz and Below

This is sub-bass, and all electronic producers should be well aware of it. It's to be found in kick drums, basslines, and any particularly weighty pads. Pads frequently don't need sub-bass, and you should EQ out any sub frequencies in other things that don't need them – FX and so on.

Consider also whether things like toms and big drums need much in the way of sub. Does it help with impact, or just get in the way? Does your kick drum even need much sub? A lot of classic jungle has kick drums with no sub at all – they just make sure they're audible, and let the bassline do all the propulsive work.

Because sub-bass involves such low frequencies, things can get messy quite quickly. Two notes close to each other will phase, and at low frequencies this means 'beating' (try using a sine wave to play two notes a semitone apart to see what we mean). Careful use of EQ will help, and consider side-chaining basslines and pads off the kick-drum to make some extra space and headroom.

100Hz – 200Hz

This region sometimes used to be considered just 'bass' and it can be quite tricky. Most of the punch of a kick drum will sit here – around 140Hz usually. Boost this area on your kick if you need a bit more 'knock' or impact on it. Basslines, unless they're a pure subby sine, will of course be in evidence, and the bottom end of your synth lines may encroach into this region. Percussive sounds such as toms and congas will have some energy here too.

So it's good to be precise. Filter out things that don't need to be here. Since kick drums don't change in pitch, it can be helpful to find out what frequency the kick punches at, and cut a few dB at that frequency out of your bassline. This will help the audibility of both. And don't forget to keep things in mono below this point – some mastering engineers will mono your whole mix below 300Hz if it's going to vinyl anyway.

200Hz – 600Hz

Welcome to the low-mids! This is where terms like 'warmth' and 'body' get bandied around. Synth parts often sound great with a little boost around 200 – 400Hz. Pianos too.

And snare drums (with the exception of toppy 808-style snares); the classic 'Pendulum snare' that you hear in so much DnB has a huge thwack at 200Hz, and sounds very powerful as a result.

Not to mention basslines; those classic garagey square waves just love a 200Hz honk.

As a result, this area can become busy and muddy very quickly. So only boost what you need to boost, and be careful with the rest. Reverbs can usually be cut around this frequency, and a lot of live hi-hats and bongos have some presence at this level.

Consider whether they really need it. If your mix is sounding overly muffled or lacking in treble, sometimes a broad but gentle cut centred around 500Hz can help you rebalance without having to boost the top end too much.

600Hz – 2kHz

The mid-range. This area will usually be quite busy; your main synths, basses, pianos, and percussion will all occupy this area; even kick drums will often have a click at the top to help them cut through the mix.

Claps usually hit at around 1kHz, vocals will typically be centred around 1kHz as well, and an excess of energy at that level can result in your mix having a congested 'nasal' sound. Careful separation is recommended!

2kHz – 5kHz

These are the upper-mids. This is where 'presence' or 'crack' may be found, depending on what you're working on. Snare drums and synth lines often benefit from a boost in this region to help them cut through the mix a little more.

But be careful, because often harshness in mixdowns is caused by over enthusiasm here; a spike at 2.5kHz can be wearing, while above about 3.5kHz we're into really piercing and unpleasant territory. So be careful with things like resonant filters; when sweeping into the higher regions, consider automating an EQ cut so that it doesn't get too harsh. Dubby delay returns and white noise style FX can cause problems here too.

A common novice mistake is to start boosting everything in the upper mids to make sure that everything comes through the mix nicely. But this will unbalance a mixdown, so gentle EQ boosts and accurate cuts are recommended. The human ear is more sensitive to frequencies between about 2 and 6kHz than any others, so moderation is the key!

6kHz – 10kHz

This is typically the area in which the top end of your percussion track and synths will be. Hi-hats, shakers, tambourines, finger snaps, crash cymbals and tech-house white noise will find themselves at home here, as will the engineers nightmare called 'sibilance'.

That's the sound vocalists make when making the 'sss' sound, but it's possible to find it in many other resonant sounds; synths, guitars, anything metallic. De-essers are good for dealing with this, or a multi-band compressor with only one band switched on, adjusted to apply to some specific frequencies.

An excess of EQ boosting in this area can lead to a mix sounding trashy or harsh, but a lack of it can give you a mix that sounds dull or lacking in treble.

10kHz – 15kHz

You'll hear this referred to as 'air' or 'sparkle' by many engineers. It's the realm of the 808 hi-hat and the ride cymbal, and it's up near the edge of what you can normally hear. As such it's important to make sure that you don't forget this region, in order to make sure you have a balanced mix that covers the whole spectrum.

You should make sure that there are audible frequencies at this level, but don't go overboard; too much detail here will be tiring on the ears. Ripping synths can sometimes be low-passed below this; reverbs and much FX too, without losing any impact.

15kHz - 20kHz

This is the very top of the human hearing range, and to be honest many people can't hear much in this region anyway. Most people above about 21 who have spent some time in nightclubs won't be able to hear very far past 16kHz, in fact.

So don't worry too much about fine detail in this area; while there should be some audible frequencies, it's not as important as the previous band!

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