EQ Basics Enhance Your Audio with Equalization Techniques

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Welcome to our quick guide to equalization, or E.Q. Let’s dive in!

In audio, the word frequency expresses how high or low a sound is. As we discussed in our Intro to Signal Flow video, sound travels through the air as waves. The speed of a sound wave is referred to as its frequency and is expressed as an amount of cycles per second, measured in a unit called Hertz. Thousands of these individual frequencies combine to form the characteristics of a sound, including pitch, timbre, articulation, and more.

EQ is a tool used in audio production to change the balance of frequencies in a given signal. One might want to change the balance of frequencies for a number of reasons, including altering a sound or instrument’s character or tonality to make it sound brighter or darker, or reducing unwanted elements like hiss or rumble.

Typical EQs are made up of multiple bands. Each band contains a range of frequencies that we can increase or decrease in volume to achieve the effect we’re after.

Let’s start by adjusting one of the bands in the middle. To begin, we’ll set the centre frequency of the band. This determines the primary frequency whose volume we will change. Next we’ll choose how much we would like the surrounding frequencies to be affected by our change. This is called the bandwidth and is usually represented with the letter Q. Though there are many different ways to use these controls, a common practice among audio engineers is to boost frequency bands using a wide bandwidth (or low Q value) or cut frequency bands using a narrow bandwidth (or high Q value).

Up to this point, we have been looking at the standard or “bell” shape of bands, however there are two other types of bands that are commonly used.

Shelf bands are bands that will affect the volume of our centre frequency and all those above it (in the case of a high shelf) or all those below it (in the case of a low shelf). And though they have many uses, they are most commonly employed to increase the overall brightness of a sound.

Lastly, we have our “cut” or “pass” bands. A low cut (or highpass) filter will eliminate everything below our centre frequency and a high cut(or lowpass) filter will eliminate everything above our centre frequency. These have a multitude of creative and practical uses, from simple audio cleanup to complex sound design.

There are many different types of EQs, from the simple and transparent one that comes in your DAW, to colourful analogue emulations and precise tools that incorporate other forms of processing.

In future videos, we will discuss even more helpful and creative ways of using equalization.

Thanks for watching and happy composing!