- Shelving EQ
- Highpass/ Lowpass Filter EQ
- Graphic EQ
- Parametric EQ, and;
- Bandpass EQ
What is Equalization?
Put simply equalization (from a music production point of view) is the process of altering sound frequencies to enhance your overall mix.
Frequencies in a song will range between around 20 and more than 20,000 Hertz (Hz). With 20Hz being the lowest sound and 20,000 being the highest. Frequencies tend to be broadly grouped into categories that may sound familiar to you, either high, mids and lows or treble, mid-range and bass.
- Lows – roughly 20-150Hz
- Low Mids – roughly 150-600Hz
- Mids – roughly 600-1.5kHz
- Upper Mids – roughly 1.5kHz-6kHz
- Highs 6kHz-20kHz
You may be familiar with bass and treble controls on your HI-FI for example. These are very simple forms of EQ and cut out either all the high or low frequencies of the sound. But in the home recording studio, probably using digital EQ in your DAW you have many more options when it comes to EQ allowing you to boost or reduce certain frequencies or ranges of frequencies on individual tracks.
In your mix, you will have sounds coming in on various tracks at all sorts of frequencies. Some even in ranges outside of the human range of hearing. These various instruments are all fighting it out to stand out in the mix and often they are trying to do so in the same frequencies. This will result in certain elements or sounds getting lost.
The temptation of a beginner may be to turn up that track and try and force it to the front of the mix but that probably won’t work, it’s not that simple.
Is it really necessary?
EQ is fairly tricky to master and you should enter the EQ world with caution if you are a beginner.
In an ideal world, no EQ would be required as you have carefully crafted your song so that no tracks clash and it all sounds great. If you keep this in mind whenever you are recording, EQ will only need to be used to tweak and polish the final song.
In fact, tweaking is how it should be used. If you find yourself using tonnes of EQ on most tracks you probably need to go back and re-record them or maybe change them. This is why it is essential for a beginner to KEEP IT SIMPLE and don’t add hundreds of instruments no matter how tempting it may be.
But it is pretty much always necessary to take your tracks to that next level just don’t overdo it!.
Corrective EQ vs Enhancement EQ
There are two reasons for using equalization in the home recording studio mixing process. These are corrective and enhancement.
Familiarizing yourself with the EQ window
On the x-axis along the bottom, you have the frequency in hertz (Hz) and on the y-axis up the side, you have the gain in decibels (dB). By altering these values (and some other things which I’ll come on to) you alter the sound. This can be done in a number of ways depending on what software you have and how accurate you need to be.
This brings us on to explaining the different types of EQ:
With a high shelf will cutting out all the frequencies above a target frequency and a low shelf cutting out all the frequencies below a target frequency.
This is effectively what the treble or bass nobs are doing on an old stereo system, they are shelving frequencies above or below a certain point.
Whereas in this example the frequencies below 100Hz have been boosted using shelving EQ.
When to use shelving EQ?
Shelving is great if you just want to boost or cut the high or low end of a particular track slightly without completely cutting it off (which is what high and low pass filter do, see below)
I will often use a slight high shelf on vocals just to add a little brightness and character to the track. I will use a low shelf with bass for example if I feel the lower frequencies are muddying the mix a little too much and I just want to reduce that low end slightly.
I very rarely use a low shelf to boost bass tracks works as bass frequencies carry a lot of energy. So I would advise against that.
High pass and low pass filter EQ
High and Low pass filters differ from shelving in that they can only eliminate certain frequencies and not boost them.
They do what they say in the name. A high pass filter allows high frequencies to pass through and therefore cuts out the lows whilst a low pass filter will let the lows pass through cutting out the highs.
This is different from in shelving where 90Hz and 60hz could be cut by the same amount.
When to use highpass or lowpass EQ?
Likewise, for a bass, most of the sound you want will be at the lower end of the frequency spectrum. Most of the sounds in the high frequencies are going to be buzzes or string slapping sounds which won’t be adding anything. So I pretty much use a lowpass EQ on all bass tracks.
A little tip is not to be as ‘aggressive’ with a lowpass filter. Have a smoother more gradual curve for the higher frequencies and you can go for a more dramatic curve for the low frequencies.
This EQ type gets its name from the graph-like appearance formed by all the sliders set at different points.
Graphic EQ has the advantage of being quick and easy to remove unwanted frequencies from a track. However, they lack accuracy. You are unlikely to use graphic EQ in the home recording studio as you will likely have access to Parametric EQ (see below) in your DAW, which will give you much more functionality.
If you do end up purchasing a graphic equalizer make sure you have as many sliders as possible to give yourself maximum control.
When to use graphic EQ?
Graphic EQs are good for quickly eliminating certain frequency ranges, which may be useful in a live setting for example. However, in your home studio, a parametric EQ does everything a graphic EQ does and much more. So I would avoid using graphic EQ.
Parametric EQ is the EQ type that you, as a home recordist, will probably end up using the most. The name parametric comes from the fact that you will have the ability to very specifically alter a number of different parameters.
These are the gain (boost or cut) and the center frequency as shown below:
But also a third value can be controlled which is the bandwidth or ‘Q’ value. This controls the range of frequencies over which the cut or boost acts. So a wider bandwidth will affect a larger range of frequency and a narrower bandwidth will affect a smaller range of frequencies as shown below:
It is worth mentioning that the value of Q varies between equalizers. This value above is taken from Ableton live but in some equalizers, the Q value is measured in the number of octaves. The constant is that the lower the Q value the wider the bandwidth so as long as you remember that you will be fine.
When to use parametric EQ?
As I say parametric EQ is probably the EQ type you will end up using the most. By being able to control very narrow frequency ranges you can cut or boost very specific parts of a track for various reasons.
Sometimes on a vocal track, you will get some unwanted frequencies coming through that may not sound immediately obvious, but will make a massive difference if cut slightly. Or often with many instruments such as drums, annoying hums or buzzes can creep in, but if you can locate the frequency where that annoying sound occurs you can get rid of it.
It is recommended that where possible parametric EQ is simply used to cut unwanted frequencies and not to boost ones that you like.
As well as getting rid of those unwanted frequencies, parametric EQ is also very useful in ‘carving out’ frequencies in a mix. This is of separating tracks from one another and allowing them to all stand out appropriately and not get lost in a muddy mess. Or maybe you want to create a dramatic loud section in a song and actually combining frequencies over a number of tracks may be desirable.
How you slot the frequencies of various instruments together in the mix varies massively depending on what you want to achieve, what genre is it? how do you want that instrument to sound? happy and energetic or slow and dramatic?
Bandpass EQ specifically affects mid-range frequencies rather than the highs or lows.
When to use bandpass EQ?
Bandpass EQ is most often used in a live setting. It is particularly handy for eliminating feedback which can occur at these mid-range frequencies.
General EQ Ranges (and the problem with EQ cheat sheets)
This section comes with a warning. I am not a fan of grouping particular types of sound into broad EQ categories. EQ ‘cheat sheets’ have become commonplace around the internet as people try and cut corners in the mixing process.
EQ cheat sheets will make broad statements such as ‘boost cymbals at 10Hz to add presence’ etc. The problem is that these statements are too broad to really be that pragmatic and yet not specific enough to get the unique sound you are after.
Cheat sheets also force you to mix with your eyes and not your ears which is a lazy habit to get into. Like with most things in life it is worth doing it properly and you will learn a lot more and become a lot better.
This is not a cheat sheet! It is a starting point for you to get an idea of where certain instruments tend to lie in the frequency spectrum and, general rules for how to add certain characters to a sound.
All the below depend on a whole manner of things from microphone type, to placement to make of instrument. But it’s a start.
To the untrained ear, the kick drum sounds like there’s little to it. Just a constant thud that keeps the rhythm of the track. But there can be much more to it than that!
The punchy, thumping sound of the kick drum usually resides between 60 and 100Hz with the body of the sound lying slightly above this between 100 and 200Hz.
Try boosting ever so slightly between 60 and 100Hz for more ‘punch’. Then reduce slightly around 500Hz to reduce the boxiness. And keep an ear out for unwanted sounds that often creep in between 200 and 2000Hz.
A key trick to get the kick to stand out in the mix though is to allow room for it by cutting some frequencies on the bass. So if you want to add body to the kick boost it between 100 and 200Hz as I mention above but also reduce the bass at those frequencies too.
Some people also like the clicking noise produced by the beater hitting the drum skin which is found between 2.5 and 5kHz.
A great snare sound is important in your mix to add real drive and purpose to a song. It isn’t surprising that a snare is accompanied or even replaced by a clap sound in many songs as it is exactly that, the musical equivalent of clapping along.
The real warmth and body of a snare tends to be found between 150 and 250Hz. With the classic snare ‘ringing’ sounds found usually between 350 and 800Hz, you may wish to cut these frequencies slightly as they can be annoying, but not too much as you will lose character.
The crisp crack that you get when the snare is hit is usually found between 8 and 10kHz.
Hi-Toms can often sound a little lifeless and lacking ‘boominess’. To add some boominess boost (or make room in the mix) between 100 and 300Hz. Also, try adding some presence at the top end above 7kHz.
Boominess for the floor tom is likely to be found between 80 and 150Hz.
I like my hi-hats to be bright and shine through and so make sure they have plenty of room in the range above 10kHz. Or use a shelf above 10kHz to boost these frequencies.
As above with the hi-hats add a shelf at the higher frequencies to bring life to the cymbals. A sound referred to as a ‘clunk’ is usually found between 100 and 300Hz.
As I keep saying don’t be tempted to just keep raising the volume of the vocals to try and make them stand out more. Yes, everyone wants the vocals to be the central focus of the track most of the time, but this is done by creating room for them and not just forcing them to the front through volume.
Add a fullness to most vocals between 120 and 150Hz (depends on singing style). Get rid of general muddiness around 200 to 250Hz and add some frequencies higher up around 3, 5 and 10Hz for clarity, presence and brightness.
Sibilance (unpleasant sounds such as S, T, and Z sounds) tend to reside between 7 and 10kHz.
Naturally, the bass doesn’t shine through in the higher frequencies it can often get very lost in a mix and just sound like a muddy mess at the bottom end (that just sounds wrong).
Cut sounds around 200 to 300Hz to try and counteract the mud. Then look to bring out frequencies at the higher end around 1KHz for that ‘plucky’ bass sound and >2.5KHz for pop and general brightness.
As I mentioned before the key is to make sure the bass guitar sits nicely in the mix with the kick drum. So make sure you are constantly checking these against one another.
You can often end up with a muddy, too boomy, sound from an acoustic guitar. To reduce this, cut frequencies below 80kHz and add some higher frequencies between 2 and 2.5kHz for clarity. Add a shelf above 7kHz for a nice bright sound.
As with the acoustic reduce the low muddy frequencies by cutting frequencies below 80kHz. Add some fullness at 240Hz and some bite at 5kHz.
Keep an eye out for annoying hum sounds between 50 and 60Hz.
Some EQ Tips and Tricks (I find useful!)
Use your ears not just your eyes
As I mentioned briefly above it is really important that you use your ears predominantly when mixing and don’t get into the lazy habit of using your eyes.
This can be tricky when there are features such as the ‘analysis’ plug-in for Ableton which will show you a graph of where peak frequencies are as a track is playing.
In the below example I have seen some frequencies in the analysis peaking at 250Hz, so I the temptation may be to instantly reduce that frequency as shown here. But that may not help you achieve what you want, it is much better to use you ears.
For that, the following tip should help.
Use frequency sweeping to find frequencies to cut or boost
A great technique to use in parametric EQ is something known as frequency sweeping.
Set your Q value quite high and add a lot of gain to make a tall narrow peak to play with and then sweep back an forth across the frequency spectrum. When you hear any nasty sounds at that same frequency you can reduce the frequency slightly at that point.
Or likewise, if you find a sound you do like, either boost it slightly or reduce other tracks at that point to make room for it.
Cut rather than boost
You are generally better to cut frequencies you don’t want than boost frequencies you do. So if you find a frequency within the bass guitar track that you want to come out in the mix more, instead of simply boosting that frequency, try reducing the frequency of other tracks in that particular area.
Boosting can add unwanted noise to a track and if it is a crowded part of the spectrum it may not actually make that much difference. Boosting can also make a track sound more artificial.
Copy and paste and invert EQs to make room for sounds to shine through
This is a great trick which I use quite a lot. As I’ve said above you are better to cut than boost if you want a particular frequency to stand out more.
So if you want to bring out the kick drum in the mix, use the sweeping technique to pick out sounds on the kick that you like and boost those EQs using a parametric EQ in your DAW. Then copy and paste the EQ plugin into your bass guitar or bass synth track for example and then make those peaks dips instead creating room for the kick drum to shine through!
Simple but very effective!