Equalizing a voice is part of the usual steps when mixing vocal tracks.
And I would even say: it is one of the essential steps, because in practice there are always small things to correct in the frequency spectrum of voice recordings. Especially if you are working in a home studio.
To give you the maximum foundation on the subject, I decided to write this article (which of course presupposes that you have a good understanding of what equalization is), structured into three main parts:
- an introductory word to clarify some important concepts;
- a detailed description of the frequencies to know for equalizing vocals, with a downloadable reference chart;
- and finally general advice on the same topic.
An Introductory Word on Vocal Equalization
Perhaps you are looking for the equalization settings to apply to your vocal tracks?
Should you boost the lows at 200 Hz? What frequencies should you cut? What Q factor should you use?
Surely, you will sometimes find standard setting lists on the Internet, like:
- Boost +5 dB at 250 Hz (Q factor: 0.7)
- Cut -3 dB at 400 Hz (Q factor: 3.0)
- etc.
However, I would not be honest if that is what I proposed to you in this article… 🙂
…indeed, there is no magical, unique EQ setting that you could apply to all your vocals.
On the other hand, a good approach to understanding how to equalize a vocal track is to start from the frequency bands that one can generally manipulate to improve a vocal track.
For example, if your sound is a bit too nasal, it is highly likely that a little subtractive equalization between 800 Hz and 2 kHz could be useful. However, the exact frequency is up to you to determine: it indeed depends on your raw recording.
That is why, in this article, I will primarily give you guidelines that will help you equalize your own vocal recordings.
To do this, we will look together at the key frequency bands to know for properly setting an EQ on a vocal track.
The Frequency Bands to Know for Equalizing a Voice
These frequency bands are those found in the diagram below, which you can download in printable PDF format by clicking here (feel free to share it around you 😉 ).
< 80 Hz: Background Noise
Often, the first equalization applied to vocals consists of cutting the lowest frequencies with a high-pass filter.
This is a fairly common practice, which is certainly not always essential, but often makes sense.
Indeed, especially below 80 Hz, the sound energy that we will find generally does not correspond to the voice itself: it can be electrical background noise, vibrations in the lows, or for example the energy from poorly captured plosives by the pop filter (you know, the dull and punchy noise when pronouncing a “p” too close to a mic).
Thus, placing a high-pass filter (with, for example, an average slope of 12 dB/oct) allows you to effectively clean the lower part of the frequency spectrum and therefore make room for other instruments.
Depending on the singer, you can of course adjust the cutoff frequency of your filter: in some cases, it is possible to go above 100 Hz!
And conversely, for some very low male voices, cutting at 80 Hz will lose energy and power.
From 100 to 300 Hz: Punch
In this frequency range, we find the fundamental frequencies of the voice.
This means that if you need a voice that is a bit more powerful, a bit more impactful, a bit more “punchy”, I recommend trying to boost this area by a few dB.
However, this frequency range is often a zone of energy accumulation from many instruments: guitar, bass, kick drum, snare drum…
Moreover, frequencies between 100 and 300 Hz tend to stand out more than usual in recordings made in small rooms (especially due to what we call modal resonances) — which is often the case in home studios.
As a result, it often happens that a vocal recording sounds muddy, too heavy. “Boomy”, as we say in English.
If this is the case, you will likely need to use your EQ to attenuate this frequency range.
However, be careful not to be too abrupt: excessive attenuation will reduce the power of your track.
From 300 to 600 Hz: “Cardboard” Frequencies
To properly equalize a voice, you need to pay extremely close attention to the frequency range roughly from 300 to 600 Hz.
Indeed, this is generally where the body of the voice will be found — that is, a certain number of harmonics characteristic of the voice.
What happens if there is too much energy in this area?
Well, simply put, you will get the infamous “cardboard box” sound. In other words, it will sound like the singer is singing in a cardboard box.
You will therefore need to use an EQ (typically a bell filter) to slightly attenuate these frequencies.
But again, be careful not to be too aggressive with this attenuation: if there is not enough energy in this frequency range, the sound will be hollow, lacking body, fragile — and it will be impossible for you to properly place your voice at the forefront of the mix.
From 800 Hz to 2 kHz: Nasal Zone
This frequency range will generally allow you to control two things:
- nasal resonances;
- the smoothness of the voice.
Depending on the singer and the microphone used, the way you approach the equalization of this range will be very different.
If you encounter unpleasant resonances, as if the person singing is speaking through their nose, a small bell filter between 800 Hz and 2 kHz will likely help improve the recording (of course, the exact frequency depends on the recording).
Depending on the level of this frequency range, the voice will seem more or less smooth.
If, on the other hand, there is not enough energy, you will likely feel that the track is pushed back, and you will have a hard time bringing it forward in the mix. So be vigilant for these types of symptoms.
From 2 to 6 kHz: Clarity
Regarding vocal equalization, the frequency range approximately from 2 kHz to 6 kHz is one of my favorites, as I find it quite easy to control.
This range is responsible for the clarity and intelligibility of the voice — we often talk about the presence of the voice.
This means that if you use an EQ to boost a frequency within this range, you will make your voice clearer and the lyrics will be easier to understand.
Tip: in addition to a slight boost between 2 and 6 kHz, don’t hesitate to make space for the vocals by attenuating this frequency range on other tracks in your piece (synths, guitars…)
If you boost too much, the vocal track will seem brittle, fragile — you may feel that it lacks body because the upper mids will be too strong compared to the lower mids we discussed earlier (300-600 Hz).
Similarly, pay attention to the sibilance of the vocals (the hissing noise produced by the letter “S”, typically) which is particularly pronounced in this frequency range…
> 6 kHz: Air
We finally arrive at the last frequency range, namely the highs above 6000 Hz.
In modern mixes, the trend is to amplify these highs, sometimes in a particularly extreme way as can be heard in this Ariana Grande track:
Indeed, raising these frequencies with a high-pass filter is a good way to add air to your mix.
In summary, this allows for an additional but subtle presence, which somehow gives the impression “ah, this mix must have cost a lot.”
However, be careful to gauge the amount of highs you add, or risk making the sound aggressive and difficult to listen to for more than a few minutes.
Finally, note that conversely, some producers tend to attenuate the highs above 10 kHz with a low-pass filter, to leave some room for other bright instruments like cymbals.
Some General Tips for Vocal Equalization
Beyond knowing the main frequency bands to consider when setting an EQ on a vocal track, some other aspects are important to keep in mind.
Here is a selection of tips that should be useful to you.
It All Starts with Recording
First of all, it is important to keep in mind that EQ is not a magic tool, and therefore if the recording is of poor quality, you will have a hard time getting something interesting out of it.
Let’s say you want a very airy, very light vocal sound — and you select a dark microphone that highlights the nasal aspect of your singing.
Well, you may be able to correct some of the problems, but you probably won’t reach your desired sound.
Thus, it is important to have the best possible recording from the start, before beginning to mix and equalize a track.
Using a microphone suitable for recording vocals is therefore a first step.
Also, make sure that the microphone positioning during recording is correct: for example, depending on the angle, the same microphone can highlight certain aspects of a voice (sibilance, nasal resonances…)
Remove Resonances
In the first part of this article, we mainly talked about the characteristic frequency bands for vocal equalization.
However, a number of resonances may appear in your recordings:
- mechanical resonance of the microphone body;
- specific resonance related to the capsule / electronics;
- resonance related to the room acoustics;
- resonance related to how the microphone reacts to the singer’s voice.
It is therefore important to remove at least the main ones (= those that are bothersome to the ear) before you start mixing your vocal tracks.
To do this, bell filters with a high Q factor are generally used, in order to have a very targeted EQ shape.
After attenuating the frequencies that are problematic, you will get something like this:
Cut Before Amplifying
Start by cutting or attenuating the frequency problems (subtractive equalization) that you hear before amplifying anything.
This advice applies to any equalization, in fact: if you first remove what is problematic, you will theoretically only have the pleasant aspects of the sound left. You will therefore need to amplify certain frequency bands less, and your equalization will be more harmonious.
Avoid Adding/Removing More Than 6 dB
I don’t like overly strict rules regarding equalization, as boosting +10 dB on a track is not always a problem — far from it.
However, the voice is still a particular and fragile instrument: a bad equalization is quickly noticeable, because as human beings we have a clear but unconscious idea of what makes a voice realistic or not.
Thus, if you find yourself with equalizations greater than 6 dB (= 4 times louder), there is probably a problem: the recording is not optimal; or the rest of the mix masks certain frequencies which misleads you; or the equalization you applied is simply not suitable.
(Of course, this paragraph does not apply to the resonances we discussed just before.)
In conclusion
There you go, you now have the maximum information to equalize your voices under good conditions.
Feel free to take one of your recordings to practice, and test the impact that different equalizations can have on the various frequency bands mentioned above.
► To continue reading, I recommend checking out this detailed guide on voice mixing.