EQ Best Practices in Audio Mixing

If you are applying EQ in audio mixing, then as a beginner you should know these best practices. Take note that this applies to any genre whether it will be rock, pop, country or even classical. Try this EQ best practices in your mix, it will drastically improve the quality of your mix and make you become a better audio mixing engineer. If you are a beginner, this is a must-read article.

Never cut or boost more than 12dB

While it will not hurt to cut or boost 12dB, one of the best practices is to minimize EQ reduction and boosting as possible. It is because it will:

a.) Introduce more audible artifacts due to some extreme boosting/cutting. This can be phase related issues or errors related to digital summing/calculations made by your DAW or plugin.

Also this will tend to worsen if you are using a combination of bad EQ plug-in, poor quality DAW (digital audio workstation) and bad recorded sound.

b.) Introduce more problems in maintaining a good level. Cutting or boosting can introduce drastic changes in volume level. An EQ boost can increase the volume of the track while an EQ cut can decrease volume. These big changes in volume can take a lot of time to balance in the mix.

c.) Can either make your mix to sound too thin, too much bass or too much mid-range presence; which is usually not good if you want a more balanced mix.

What you will do if you really need to cut and boost more than 12dB?

1.) Listen to the track very carefully. Was it badly recorded? Sometimes a bad recording can introduce serious tonal problems. These are caused by a lot of factors, for example:

a.) Recording or tracking in an environment that does not have flat EQ response. Supposing you want a more mid-range sounding acoustic guitar but you are placing the guitar amplifier cabinet facing towards the corner of the room. Since corners can naturally boost the bass levels, you can hardly get that mid-range sounding guitar in the recording.

Instead what you will get is boomy sounding guitar. Even if you cut the bass frequencies on the guitar by more than 12dB, it does not sound as good and natural as those captured correctly. You really need to record your tracks correctly to avoid drastic changes in the EQ. In the above example, the guitar amplifier cabinets or microphone can be placed away from the corners of the room and in a more spacey surrounding to capture the natural mid-range sound of the guitar.

Another example is that the guitar already includes an EQ on it (included with the pickup amplifier) with pre-defined settings. It makes sense to turn all the EQ knobs to flat so that the guitar sound can be captured as flat as possible.

2.) If re-recording seems impossible; then use a highly accurate EQ made for this purpose. A good example is the Waves LinEQ plugin.

You will be able to set critical parameters such as Low Ripple, etc. all settings that you need to minimize the undesirable effect of drastic EQ changes.

3.) Do not make big EQ changes on all of your tracks. Making big changes such as reducing or cutting 12dB may sound reasonable for one track which cannot be re-recorded. But doing it for all of your tracks are not recommended. Fixing a recording related EQ issue is best solved by re-recording.

Always use a highly accurate Parametric EQ

Parametric EQ are important surgical tools in audio mixing that you can use to shape the sound. You should be using them. For most beginners that are just new in audio mixing; they mostly do not know these tools.

Instead what they know is a graphic EQ since these are the EQ they used to see almost every day in their mp3 players, etc. For example this is a graphic EQ:

Unfortunately, graphic EQ does not allow you to set how narrow or wide are the EQ settings. For more accuracy, you should be using a parametric EQ which is suitable for this job. Take a look at this parametric EQ and notice that it has one additional parameter setting which is Q:

Do not use a cheap and low quality EQ because they have poor accuracy. Instead invest in quality digital audio mixing plug-ins like Waves.

Cut more, Boost Less

Boosting adds more issues than cutting in mixing. It is why it is recommended that in all EQ problems you would be focusing more on cutting than boosting.

Let me illustrate an example: Supposing you are mixing a track with weak vocal mid-range sound. You listen and find out that the guitar mid-range strumming frequencies are conflicting with the vocal sound. You have two choices here to solve this EQ issue but only one is recommended, see below.

NOT RECOMMENDED = Boost vocal mid-range frequencies until it dominates the guitar sound thus making it sound clear in the mix.

RECOMMENDED = Cut guitar mid-range until the vocal sits properly in the mix.

See the difference? The second option is more recommended and this is how the pros in mixing would solve this issue. Instead of boosting vocal EQ, you would simply be cutting the offending frequency which is the guitar mid-range. These results in clarity without un-naturally increasing the overall volume of the mix which can either leads to undesirable:

a.) Distortion or clipping
b.) Less headroom, since boosting EQ pushes levels further up.

Boost wide and Cut Narrow

Boosting is more desirable with very wide Q done at low gain. For example if you want a more vocal presence; it would be much beneficial to boost with:

+2dB Q=0.7 at 1000Hz

Take note that this is a wide boost since Q=0.7. This would have a profound effect on the vocal presence in the mix. In my experience, Q below 1.4 is considered to be very wide. For cutting frequencies, my minimum preferred Q would be 1.4 (usually above such as 2.0), cutting EQ less than 1.4 is considered very wide and is not advisable since it significantly alters the sound of instrument other than making it clear in the mix. For boosting, I would prefer values around 1.4 to 1.0 or even 0.7~0.8 for very wide boost with subtle boosting gain.

On the other hand, cutting is more desirable when done at narrow Q at higher reduction gain. This is necessary for precise and accurate EQ in solving tonal issues. A classic example is removing the boxy sound of the kick drum. Sometimes by sweeping through parametric EQ you should find this somewhere 300Hz to 400Hz (a very narrow range). And to remove this boxy sound, you would be applying like:

400Hz Q=5.0 -9dB

Now that’s a high cut done at a narrow bandwidth.

Watch out for clipping in your EQ output meters

Often beginners do not know that the output of EQ can be clipped particularly if you are boosting something. This is often one of the reasons why you should not be always boosting when doing EQ because of the high possibility that the output of the EQ is clipped.

Clipping in digital is unacceptable and can seriously degrade the quality of your mix. If you have a parametric EQ with output level meters, then use it and watch out for red (clipping). If it occurs; take action immediately by doing one of the following:

a.) Lower the input level.
b.) Lower the boost amount.

Content last updated on June 19, 2012