EQ Frequency Guide: An introduction to the frequency spectrum

EQ Frequency Guide:

If you’re recording, mixing or mastering your own music, then it’s almost certain that you’ll be using an equaliser (or EQ). But to use an EQ effectively, you need to understand the frequency spectrum. This article gives you an introduction to the frequency spectrum with our simple EQ frequency guide.

Understanding the frequency spectrum:

When you open up an EQ plugin inside your DAW, you may be faced with a number of different scenarios. Some EQ plugins feature graphs which show you the frequency spectrum. Others don’t. That’s because different equalisers operate in different ways. One thing that all equalisers have in common however, is that they’re there to control the way we hear the frequencies of what ever channel they are placed on.

The numbers along the bottom of this graph, taken from the ProTools EQ 3 4 band plugin, represent the frequency spectrum:

I’m sure that you’re already familiar with the idea of low, mid and high sounds. But how do those terms translate to frequencies like the ones we see here?

Well, the numbers shown here represent 20 hertz (Hz) to 20 kilohertz (kHz). You may also see this referred to as 20 hertz to 20,000 hertz.

20 Hz – 20,000 Hz represents all of the frequencies that can be heard by human beings. It is worth noting however, that our ability to hear higher frequencies decreases with age. Most adults can only hear frequencies up to 16,000 hertz.

Low, mid and high frequency sounds fall between the following frequencies…

EQ Frequency guide – Low, Mid & High:

Low = 20Hz – 300Hz

Mid = 300Hz – 5kHz

High = 5kHz – 20kHz

Knowing this gives you a great indication of how frequencies translate to the types of sound that we’re familiar with. But we can go further. We can break each of the high, mid and low groups of sounds into more specific categories.

EQ Frequency guide – Low end:

Sub Bass = 20Hz – 40Hz

Low End = 40Hz – 160Hz

Upper Low End = 160Hz – 300Hz

EQ Frequency guide – Mids:

Low Mids = 300Hz – 800kHz

Mids = 800Hz – 2.5kHz

High Mids = 2.5kHz – 5kHz

EQ Frequency guide – High end:

High End = 5kHz – 10kHz

Ultra High = 10kHz – 20kHz

So a full breakdown of the frequency spectrum would look like this…

Complete EQ Frequency guide:

20Hz – 40Hz = Sub Bass

40Hz – 160Hz = Low End

160Hz – 300Hz = Upper Low End

300Hz – 800kHz = Low Mids

800Hz – 2.5kHz = Mids

2.5kHz – 5kHz = High Mids

5kHz – 10kHz = High End

10kHz – 20kHz = Ultra High

So now, armed with the knowledge of the types of sounds that are occurring across the whole frequency spectrum, we can cut, boost or filter a specific part of the spectrum to alter the way that type of sound is being reproduced.

So tell me, do you think that knowing more about how different bands of frequencies sound will help you make better EQ decisions? Leave your thoughts below.