Equalizer is an important topic for music producers. It’s fundamental and tricky, so beginners often spend most of their time when mixing music setting it up. For such a big topic, it’s important to have a clear understanding of the basics. Audio equalization is a powerful tool, and with not enough knowledge, you can easily do more harm than good.
A good starting point for deciding when to use EQ when mixing is to turn it off.
Try balancing levels between instruments using the faders. After that, if you’re having problems with what you want to hear, it’s time to think about audio equalization.
This tool solves problems with frequency masking. It’s about the “turbidity” that occurs when instruments with overlapping frequencies collide with each other, making it difficult to hear simultaneous sounds clearly. For example, if you’re having trouble listening to a bass drum over a bass guitar, that’s the job right there for EQ.
This article will cover everything you need to know to start using EQ like a pro – from the ground up.
EQ settings
Audio equalization parameters are used to set filters that will boost or cut the frequencies of an audio signal. Common parameters you’ll find include:
Frequency – selects the one you want to boost or cut.
Q – (center frequency divided by bandwidth) controls the bandwidth – how wide or narrow the gain or cutoff will be. In other words, you can determine the range that the audio equalization will affect. Higher Q values will give you a narrower bandwidth, while lower Q values will allow you to amplify or attenuate a wider range.
Gain – determines how much the selected frequencies are cut or amplified.
Type – allows you to select the shape of the filter for the selected bandwidth.
Slope – sets the steepness of the filter for the upper or lower frequencies.
Equalization Principles
Audio equalization in music is the process of adjusting the level or amplitude of certain frequencies to produce a clean and balanced mix.
Digging even deeper, music is a combination of sound waves vibrating at different frequencies. Any sound can be described by its frequency. It defines the pitch of a note. The frequency vibrating at 440 Hz is the note “A” in modern music.
Of course, audio equalization in music is much more complex than pure sine tones. If you press the open A string on your guitar and run the result through a frequency analyzer, you’ll see more than just a thin needle pulsing at one particular frequency. You will see a lot of them.
There are many factors involved. The design of each instrument contributes to its particular harmonic content. That said, if you play a note on one guitar, it would not have the same timbral composition as another. But what happens when we run the music through the frequency analyzer?
We see many frequencies, and they all happen at the same time! Now we can get to what audio equalization is, in simple terms. It’s like the volume control on your phone-the buttons that make music louder or quieter. Equalizer is basically a level control for individual frequencies. It allows you to focus on a selected group of frequencies, giving you the ability to determine how to affect that group. You can take a bunch of frequencies and boost them (“boost”) or select just a few and lower them (“cut”).
Tones and frequencies
Imagine a French horn and an electric guitar playing the same note “A” = 440 Hz.
What makes them sound different? Both instruments play the note with the same fundamental frequency, but each has its own unique timbre. The timbre of a sound gives our brain a lot of information about what it represents in the real world.
Unique, recognizable timbres are a property of all complex sounds. All complex sounds in audio equalization can be broken down into simple sine wave components. These basic components are called partial components.
If the partial ones are related to the main whole ratio (i.e., 2:1, 3:1, 4:1, etc.), they are harmonic. If not, they are non-harmonic.
A very harmonious sound, such as the string of a bowed cello, is rich in evenly connected parts, whereas a very unharmonious sound, such as the rattle of a cymbal, consists only of unconnected parts.
Types of audio equalization
Shelf EQ.
Shelf EQ affects all frequencies above or below a certain point. High cuts off everything above the target frequency, and low cuts off everything below the target frequency.
Shelf EQ is mostly used for the highest or lowest frequencies.
Graphic EQ
The Graphic EQ may be familiar to you from old school stereos or amplifiers. The frequencies are grouped into broader categories, and you can trim or boost each of these categories to shape the sound. This type of audio equalization gets its name because of the graphic look formed by all the sliders set at different points.
The advantage of a graphic equalizer is that it quickly and easily removes unwanted frequencies from a track. However, they lack precision. You’re unlikely to use this type in your home recording studio, as you’ll probably have access to a parametric equalizer in your DAW, which will give you much more functionality.
Parametric EQ
Parametric EQ is the type of audio equalization that you, as a home audio engineer, are likely to use most often. The parametric name comes from the fact that you will have the ability to change a number of different parameters very precisely. These are gain (up or down) and center frequency.
But you can also control a third value, which is the bandwidth or “Q” value. This parameter controls the range of frequencies that the cutoff or gain acts on. Thus, in audio equalization, a wider bandwidth will affect a larger range, and a narrower bandwidth will affect a smaller range.
Highpass and Lowpass Equalizer
High-pass and low-pass filters differ from shelf filters in that they can only eliminate certain frequencies, not amplify them.
An audio equalization high-pass filter lets high frequencies through and therefore cuts off low frequencies, while a low-pass filter lets low frequencies through by cutting off high frequencies.
Band EQ
A bandpass equalizer affects the midrange frequencies rather than the highs or lows.
This type of audio equalization is most commonly used in live performance. It is especially useful for eliminating feedback effects that can occur at these midrange frequencies.