Equalization - Basic theory and practical application


After having dealt with dynamics and compression in the last article, we now want to turn to another big topic in audio editing and production: equalization. Not only the bedroom or professional music producer knows about the term equalizer as a tool for audio editing in recording, mixing and mastering. Even far away from the sound studio, we encounter EQs in everyday life, for example in the home hi-fi system, in the car radio, or in the smartphone. In this article I'll introduce you to the two big equalizer types, the graphical EQ and the parametric EQ. Let's look at the most important parameters: frequency, gain and bandwith control (Q). I'll also introduce you to the different filter types and settings - peak EQ, high-pass, low-pass, high-shelf and low-shelf - and give you a few tips for your productions.

You probably know one of the following situations: you are recording a vocal or guitar part and the sound is muddy or rumbling. Or your hi-hat sample sounds too harsh in context and the bass drum has no bottom. These examples all have one thing in common: they refer to the frequency components of the audio signal. Each sound consists of different frequency components.

And these are influenced by the equalizer: it controls the composition of the frequencies of the sound and, depending on the version, can lower or raise certain frequencies in the entire frequency spectrum of the sound. In short: with an equalizer you control the frequency response of audio signals.