Mixing music – The importance of learning to identify key frequencies

Mixing music - Learning and understanding key frequencies

It is extremely common for musicians in the year 2015 to record their own music at home. We invest some money in a computer, an interface, monitors, a microphone and our instruments and we are good to go! We all want our recordings to sound as good as they can so unless we have the budget to send our tracks off to be ‘professionally’ mixed, we get involved in the black art of mixing.

If you are recording on a computer then the software you are using probably has an equalizer bundled with it as standard. At the most basic level, an equalizer can cut and boost parts of the audio spectrum. People often use generic terms like ‘treble’ and ‘bass’ to describe different parts of the audio spectrum but we often want to be a little more surgical in our description of sound and the changes we might make to it.


Here’s a quick overview of sound and how it works.

Sound is the energy produced when something vibrates. Think of a drum – you hit the drum and the vibrating skin causes the air around it to vibrate. The molecules of air then bump in to other molecules that are next to them. This process goes on and in this way; energy is passed in all directions from the initial sound source. Energy is lost along the way and eventually the sound dies out as the energy is used up. The molecules of air vibrate in the same direction that the sound is travelling and this causes areas where air molecules are more bunched up and some where they are more spread out. When the wave arrives at your ear, the air inside your ear canal vibrates, causing your ear drum to vibrate too. Your brain then perceives this vibration as a sound.

Phew, school physics lesson over with…

That sound wave that arrived at your ear will make your ear drum vibrate in complex ways.


The complexity of this vibration contains all the information about the sound – it’s fundamental frequency and overtones.

Great mixing engineers have a ‘golden ear’ for being able to clearly ‘hear’ sounds and their frequency content and decided which ones will work well together. They will be able to change the frequency content of a sound so that it fits with other ones. Do these people have genetically different ears or brains? Probably not. They have just trained themselves over the years to be able to accurately identify different parts of the audio spectrum, know how they sound and know what to do to change things in a pleasing way.


The importance of training yourself.

Ok, imagine you are mixing some parts of a song together. The drums sound ok but when you put the bass, guitars and vocals in there too the whole thing sounds ‘mushy’ and you can’t hear any separation.

A good mixing engineer will be able to hear where frequencies in the different sounds are overlapping.

If they remove some of that frequency from one instrument then they wont be overlapping any more. The saying ‘each instrument has it’s own space in the mix’ is a way to describe this approach.


So how do I train myself to recognise and know what frequencies I should be cutting/boosting?

You need to go and practice! Watch legendary mix engineer Dave Pensado talk about ear training: Into The Lair #57 – Ear Training Part 1. He describes how in the past he’s taken time to play a piece of music through an equalizer whilst he boosted and cut different frequencies whilst listening for the difference it makes. By spending time doing this you are training yourself to be able to recognize what each frequency band sounds like. The music would be a familiar song to you so you can really hear how the boosts change the sound that you are used to.

Some people use words to describe music and how it sounds – boomy, nasal, tinny, bassy and boxy are all words which describe sounds which have different frequency profiles.

Go and listen to a piece of music whilst boosting a known frequency range and you will change it in an audible way. Do this for a range of frequencies – maybe 32Hz, 64Hz, 125Hz, 250Hz, 500Hz, 1kHz, 2kHz, 4kHz, 8kHz, 16kHz and remember their sounds – possible assign your own name to each of them so you remember and internalize the sound/feeling of them.

Another good tool to use is the Harman – How to listen online training course. This is a software training course that will teach you to recognise some of the most important frequency bands. You will hear a piece of music and there will then be a BIG cut or boost at a certain frequency. The software will ask you to identify the frequency that has changed. Once you get the hang of this then the cut/boost becomes smaller. Your ear needs to start to be very keen to hear these subtle changes.

This is why top mixing engineers cost a lot of money; they are very good at making subtle improvements to your music which requires skills learnt over hours of practice.



Get practicing! The equalizer bundled with your software will allow you to sweep through a piece of music and cut/boost certain frequencies whilst you learn how they sound. Your can use any sound source – a full piece of music, a solo vocal part or any instrument parts. You will start to recognize that each instrument has certain frequencies which are most important in how it sounds.

This skill will actually help you in other areas – specifically with writing and arranging music. When you understand about the fundamental nature of the sound of certain instruments, you intuitively know which ones will work together best.

It’s advisable to continue training your ear to be able to hear and identify frequencies in sound. It can take a long time to develop a truly expert ear but it will be worth it in the long run!

Mitch Cockman
Musician and blogger at Yorkshire Bass Player
Mitch is a musician, band leader and web designer from Yorkshire. He is primarily a bass player and you can find links to most of his work at:

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