Equalizing an acoustic guitar is more complicated than it seems, especially for beginner home studio enthusiasts.
Indeed, while recording may seem quite simple — integrating an acoustic guitar track into your mix often reveals a number of issues that are quite difficult to correct with an EQ: unpleasant resonances in the lows, hand noise on the strings…
Therefore, I propose through this article to give you as many tips and tricks as possible to guide you in mastering your equalizers on this specific instrument.
Happy reading! 🙂
An Introduction to Acoustic Guitar Equalization
When you clicked to read this article, perhaps you were looking for standard equalization settings to apply to your acoustic guitar recordings.
Maybe you imagined finding advice like “cut the highs at 8000 Hz with a low-pass filter” or “boost the mids by 4 dB at 320 Hz”.
This is what you often find online — and it is true that it makes sense, when you are an amateur home studio enthusiast, to look for “the right way to do” to use this or that effect.
However, especially in the case of equalizers, I wouldn’t be helping you much if I gave you this kind of advice.
Simply because it all depends on the original recording! 🙂
Imagine you have a very dark jumbo guitar that you recorded with a microphone emphasizing the lows.
In this case, you will likely end up with too much bass and need to attenuate it.
Now imagine you are recording with a very bright parlor guitar and a microphone whose frequency response in the lows is attenuated: in this case, your sound may lack density, and you will probably need to lift the lows with a bell filter or low shelf.
Similarly, the equalization you will do on your acoustic guitar will always depend on the musical style: if you are recording a guitar/voice piece, the guitar will be highlighted much more than if it simply serves as accompaniment in a more complex piece.
In short, you will have understood from these examples: there is no magic EQ setting for acoustic guitar.
On the other hand, to properly equalize this instrument, it is important to learn to hear what is happening on certain frequency bands — to be able to correct issues when you hear them.
And that is precisely what we will see in this article…
The Frequency Bands to Know for Equalizing an Acoustic Guitar
Here are the frequency bands we will specifically discuss. You can download the diagram in printable PDF format by clicking here (feel free to share it around you 😉 ).
< 50 – 80 Hz: Background Noise
Often in acoustic guitar recordings, the lowest frequencies contain what I simplify as “background noise”.
That is to say energy related to sounds that are simply not the ones we wish to record in the first place.
It can be, for example:
- an electrical background noise related to the preamp’s power supply;
- hum from devices in the room (air conditioning, computer…);
- noise from the street next door;
- low vibrations related to the instrument but that we do not wish to capture;
- etc.
It is therefore generally a good practice to attenuate or cut the corresponding frequencies to prevent this sound energy from taking up too much space in the mix (or even harming the definition of your bass line or kick drum).
Generally, this is realized by a high-pass filter set between 50 and 80 Hz, for example with a slope of 18 dB per octave (but of course you can experiment).
Be careful not to go too high, since the fundamental frequency of the lowest string on a guitar (E2) is 82.41 Hz.
70 – 100 Hz: Density
Now that we have set aside the background noise, we can focus on the frequencies that are more important for the guitar.
In the 70 to 100 Hz range, you will generally find energy that contributes to the density of the recording.
That is to say, the ability of your guitar track to have punch, to be sufficiently impactful and powerful.
If these frequencies are underrepresented, your guitar will sound quite weak, quite fragile — in this case, feel free to use your EQ and boost by a few dB.
If, on the contrary, this frequency range has too much energy, you will hear marked resonances and your track will contribute to making the low frequencies of your mix muddy.
Note: Also note that if your acoustic guitar is just for accompaniment and does not play a primary role in the piece, you may not need to highlight this frequency range too much, as it is rather the bass and kick drum that will be emphasized at this level.
100 – 350 Hz: The Complicated Zone
Yes, just like with vocal equalization, setting an EQ correctly on an acoustic guitar track is not always simple.
This frequency range from 100 to 350 Hz is often complicated to equalize because a lot is happening there. It is therefore important to manage to adjust it without harming the balance of the recording.
First of all, note that the quality of the recording is essential to minimize the EQ adjustments that need to be applied at this level.
Indeed, we are right at the fundamental frequencies of the acoustic guitar (which range from 82.41 Hz to 329.63 Hz in standard tuning) — and we also find different resonances of the instrument emitted at the soundhole.
It is therefore important to properly position your microphone during recording to have the cleanest sound possible.
Often, you will need to attenuate at least some frequencies between 100 and 250 Hz to control the resonances and make the acoustic guitar track less “boomy,” as the English speakers say, meaning less muddy in the lows and low-mids.
In the higher part of the frequency range, let’s say between 200 and 350 Hz, you will find more of the body of the instrument.
If your sound seems too thin, too fragile, it may be worth boosting these frequencies. However, be careful, you will notice that the sound quickly becomes muddy and cluttered. Feel free to listen to the rest of the mix at the same time as your acoustic guitar track when you intervene on these frequencies in particular.
400 – 800 Hz: “Cardboard” Frequencies
As with many instruments, this frequency range generates a “cardboard box” sound when it is overly emphasized, making the mids particularly cluttered.
Note that these problems can extend up to about 2 kHz, taking on a more nasal, metallic appearance (the choice of strings is therefore necessarily important!).
However, as a general rule, unless you notice a major problem of this type, it is not really necessary to equalize this frequency range if the recording has been well done.
Tip: to properly identify the type of sound I am talking about, take an acoustic guitar track and an EQ and boost +12 dB around 500 Hz. Take the time to really listen to the sound produced.
2 – 6 kHz: Clarity
The frequency range from 2000 to 6000 Hz is generally the easiest to control.
This is where you will primarily find the sharp and cutting aspect of the strings.
Just like with the voice, if you want to bring the guitar to the forefront of the mix and enhance its impact, adding 2 or 3 dB on these frequencies should take you in the right direction.
If, on the other hand, your guitar is too aggressive or too cold, feel free to reduce them a bit with a bell filter.
Note that generally, it’s the voice that is prioritized on these frequencies: if that’s the case in your mix, avoid boosting the acoustic guitar on them as well.
> 8 kHz: Air
Finally, there is a nice and relatively easy technique to add brilliance and give space to your acoustic guitar recordings — it’s often referred to as “adding air”.
All you need to do is take a high-shelf filter (or why not a bell filter, but personally I’m less of a fan) and gently lift the highs above 8 kHz (it’s up to you to identify the exact ideal cutoff frequency for your mix).
Instantly, the sound becomes more open.
However, be careful: the effect is often very pleasant, but the risk of overdoing it is real. A few decibels are usually sufficient.
Some general tips for equalizing acoustic guitar
Indeed, it is important, even essential, to have a good understanding of the main frequency bands associated with the acoustic guitar to properly equalize its tracks.
However, in addition, here are some more general tips that will also help you manipulate your EQs with this instrument.
Equalize from the recording
Be careful, don’t take this chapter title too literally.
I do not recommend equalizing your recordings at the time of recording.
What I want to emphasize is that the way you record your acoustic guitar influences the amount and complexity of the equalization you will do afterward.
In the early paragraphs of the article, I used the example of the type of guitar: if you want a bright sound, avoid using a dark guitar.
And vice versa.
Don’t forget to change the strings before any serious recording session: the older the strings get, the duller the sound. So put on new strings and enjoy a clearer and higher-quality sound, which will require less equalization to be pleasant.
Of course, the choice of microphone(s) and the recording technique used strongly influence the frequency distribution of the sound energy: read my article on recording acoustic guitar and test different recording methods to find the one that best suits the sound you are looking for.
The better the recording, the less you will need to use an equalizer during mixing.
Sometimes, you won’t even need EQ!
Equalize in groups
If you have several similar acoustic guitar tracks (for example, to pan them left and right), feel free to group them in a bus (track group) to process them similarly.
Indeed, we sometimes have the reflex to think that to do better, it’s better to be more meticulous and equalize each track independently.
In reality, this often wastes time but is also a source of errors, which can make your mix more unstable.
So simplify the approach and group your acoustic guitar tracks before adding plugins.
Control resonances
We mentioned earlier that certain resonances related to the instrument could appear in the low mids.
However, the entire frequency spectrum is potentially subject to resonances: these can indeed come from the selected microphone, the electrical network, or the acoustics of the room.
It is therefore important, if you hear such problems in your recordings and especially if they stand out in the mix, to attenuate them with a bell filter with a high Q factor.
Sometimes a reduction of a few dB is enough, but in some cases, you will need to be more aggressive and achieve something like this:
Attenuate before amplifying
Finally, one last piece of advice that applies to both acoustic guitar equalization and any other instrument: before amplifying frequency bands, start by cutting those that are problematic.
Indeed, if you attenuate the most problematic aspects of the sound, you will theoretically be left with “only what sounds good”.
By doing so, you will no longer need (or much less) to amplify the rest of the frequency spectrum.
In conclusion
There you go, you are now a specialist in acoustic guitar equalization! 😉
At least, you have all the information to practice recognizing the impact of equalization on a specific frequency band concerning the acoustic guitar.
So don’t hesitate to apply all the tips from this article the next time you equalize a track of this instrument!
► Continue reading with my detailed guide on recording acoustic guitar.