Harmonic mixing is something that you should understand as a DJ and can really help producers organise their library of sounds. You may have heard of things like the circle of fifths or how good DJs use metadata to label their music correctly. The information and tools you need are all below.

This article is packed with information so feel free to jump to the sections that interest you…

Intro to keys
How it works
Circle Of Fifths
Mixed In Key
Note for Producers

Even if you have little or no knowledge of music theory you can use the tips and software below to quickly get to grips with harmonic mixing. So don’t be put off if you don’t know anything Major about your Relatives.

Intro To Keys

When a couple of songs are playing together and they sound great it’s usually because they are in the same key or one of its relatives.

Each key is made up of a scale of notes. Each ‘major’ key has a relative ‘minor’ key that will have the same notes but with a different ‘root’ note (to keep it simple that’s the first note in the scale).

Relative musical keys.
The key of ‘C major’ on the top, and ‘A minor’ underneath. The lines connect the notes that are the same. The first note on the left is the root note.
‘C’ is the root note above. ‘A’ is the root note below it. You can see that the notes are the same in both scales but begin at a different note.

Also, the songs might sound good even though they are not in the same key. For example, they might have only one note different in their scale and avoid sounding unpleasant.

Ever mix two songs and they sound out of tune?

That’s why it’s good to know what key your songs are in and how to mix harmonically between them.

Loopcloud Music App from Loopmasters.com

How Harmonic Mixing works

Years ago DJs and musicians used to sit with a piano or similar and would listen to their records very carefully. The idea was to play different notes on the piano and try to match the tone to the song. This gave you an idea of what key the song or sample was in. Something very important to someone wanting to remix, do mash-ups, or just have a tight sounding DJ set.

We’re lucky that we don’t need to do that anymore. Thankfully there are some clever bits of software that will analyse music or any samples of sound and determine what key they are in. This information can then be saved within the song’s metadata. When you load it into your DJ decks or software like Traktor or Serato, this data can be seen.
If you take requests you will be able to check if it will fit with the song you are currently playing without ever having to load it onto a deck.

The really clever part though is when you change the key codes to something that’s really easy to remember. Meaning even if you have no idea what the keys and scales are you’ll still know which songs are probably going to be in tune with each other. All at a quick glance too.

C major and A minor being relative to each other might be hard to remember. Trying to remember that C major will also mix well with G major and F major is going to be impossible without practice.

Harmonic mixing key code usage example.
Example of how to use the circle of fifths with custom key codes.

However, if we use custom codes and change it to this…

C major (8B)

A minor (8A)

G major (9B)

F major (7B)

We can see it’s a lot easier to navigate. You don’t have to remember anything.

You just need to know that you can go one number up.
Or down one number.
The letter must stay the same.
(9A to 10A or 8A) (1A to 2A or 12A)

Or you can change the letter, but you must stay at the same number.
(1B to 1A) (11A to 11B)

There are even more ways you can use this system but let’s keep things simple for now.

The custom code I’m using here is known as the Camelot system and it is not the only type of custom codes that people commonly use.

Also, note that the Camelot coding system is actually copyrighted to Mixed In Key.

See below for more examples…

Different key codes used for harmonic mixing.

Circle of Fifths

Whether you use the custom key codes I’ve mentioned or if you decide to learn the proper names of the keys I would highly suggest you get a visual image of the Circle of fifths. Feel free to use the ones above/in this article or search for ‘circle of fifths’ or ‘Camelot wheel’ and pick one you like.

ikolay Diletsky's circle of fifths in Idea grammatiki musikiyskoy (Moscow, 1679)
Nikolay Diletsky‘s circle of fifths in Idea grammatiki musikiyskoy (Moscow, 1679)

The circle’s design dates back hundreds of years. It is a way to help musicians visualise and understand some of the musical relationships between keys and pitches. It was originally used to help musicians compose and harmonise melodies, build chords or change the key during the composition to change the ‘mood’ of the music.

Circle of fifths used for harmonic mixing.

Check the wiki here for more information:


To put this all into practice you will need a program that will analyse your music collection and determine the key. Then label them in a way that is useful to you and easy to understand.

The first program I would suggest is the incredible work of Ibrahim Shaath, and entirley free!
A great starting point if you just want to look into harmonic mixing without investing into premium software.

Keyfinder software for harmonic mixing. Main view

Pros & Cons

I still use Keyfinder now. I feel it is up to the job and very simple to use. It’s also a self-contained program, so I can run it directly off a USB stick if I wanted to. You have the options to label tracks in different ways and in different fields (like ‘comments’ or ‘filename’) and it supports custom codes.

I analysed all my songs and my entire sample library with great success. It is rare that it fails to assign a key to a song or sample. And it is rare that it gets a key wrong.

I think the only issue with Keyfinder is it doesn’t have a team of people working on it. Unfortunately, support for the Windows version has discontinued (It still works, I’m still using it to this date). The Mac version does still get updated. Don’t let this put you off though. I feel that the only real difference between this and its competitors are the extra features they have. Keyfinder does what it says and nothing more.

Go check it out…

Keyfinder software for harmonic mixing. Settings view

Mixed in Key

The next program I would suggest isn’t free, but it does come with many more features than Keyfinder, and has better support and regular updates.

If you are a professional DJ the extra features in Mixed In Key may be a deal breaker. I know a lot of people still use Mixed In Key even though many DJ Programs like Traktor have built in key and bpm detection.

Mixed In Key software for harmonic mixing. Collection view

Pros & Cons

To be honest, Mixed In Key is fantastic. I used to use it back when it was only on version 2/3 before I used Keyfinder. However, for me, I didn’t want to pay for the newer versions and upgrades.
Just like Keyfinder, it is very accurate, and some argue it is the best one out there for key detection.

Not only can this software detect the key and bpm it also can detect the energy levels of the music and gives them a rating. This helps you maintain the correct energy that the dancefloor is asking for. Need something more chilled, or a big banger? The energy detection will really help.

Mixed In Key software for harmonic mixing. Settings view

Other features include an ID3 tag cleaner, to get rid of messy metadata. A very customisable tagging system. A built-in piano roll, so you can play notes alongside the music to check them by ear. Finally, there’s a clever feature that detects potential cue points and then saves them in a way that can be used in Traktor and Serato

Overall, Mixed In Key is your goto if you are a professional or serious DJ, and don’t mind chucking a few quid on a decent bit of kit that will really help improve your harmonic mixing.

Check out the official site here…

Quick Note for Producers

Previously I mentioned how it’s important for producers to understand harmonic mixing. Not all producers are DJs, and it’s good to be aware of the methods DJs are using when they play your music. Also, it can help improve the technicality of your music.

Understanding how musical keys work can really help improve your music. A commonly used technique is a classic key change. Often heard in popular music, maybe the song starts in c major but has a part later on where the song ‘drops’ to its relative minor (a minor) This changes the mood of the song from being ‘happy’ to a lot more ‘moody’ sounding. Perfect for those heartbroken love songs!

The circle of fifths is a great reference for musicians and the tools here are perfect to help someone with no experience of music theory get to grips with the basics of scales and keys.

If you have a large sample library and you are a music producer I would grab a copy of either Keyfinder or Mixed In Key and analyse all of your samples.
A well-organised sample library is essential to a faster workflow.

Harmonic Mixing organisation of samples in Ableton
Example of folder organisation.

I have my kick drums, snares, hi-hats, bass shots, risers and so on, all in their own folder. All the samples in there have all been key detected. Now when I start composing a melody that happens to be in F major and I’m ready to replace the click track with a kick drum. I can jump straight into my sample library and start auditioning all the kicks that are in F major until I find one that I am happy with.


Harmonic mixing may seem daunting at first but by using software and some reference images you will soon be doing it without a second thought.
Try mixing harmonically and record it. When you compare that mix with one that isn’t harmonic you will really hear the difference.
The reason why those old classic DJs became so big was that they were naturally good at working harmonically. Like beatmatching, it is a skill that can be learnt but some people are naturally better at than others.

And that leads to my final and most important point

These programs are not perfect. There will be mistakes and they are not always correct. They are designed to detect only a few of the keys that exist. The minor and major keys are very common but a lot of music has key changes in it. Plus there are many more keys out there which aren’t taken into account. For example, it is very common for scales to be different, like harmonic or melodic minor. Slightly changing the notes or introducing accidentals can really mess up key detection software and that’s where the most powerful tool takes the top spot. The human ear of course!

So if you really want to be good at harmonic mixing, or you want to have a great knowledge of musical theory then the best thing to do is book yourself some music lessons and start learning the proper way.
These key detection programs are incredibly accurate but they are still a shortcut, a workaround. The DJs that have taken the time to learn and understand music better will always stand out from the crowd…

Music Software Bundles from Pluginboutique.com

If you want to learn more and don’t fancy booking with a tutor then why not jump on wikipedia. You can click on all the terms used and check out what they mean.

Harmonic mixing or key mixing (also referred to as mixing in key) is a DJ’s continuous mix between two pre-recorded tracks that are most often either in the same key, or their keys are relative or in a subdominant or dominant relationship with one another.
The primary goal of harmonic mixing is to create a smooth transition between songs. Songs in the same key do not generate a dissonant tone when mixed. This technique enables DJs to create a harmonious and consonant mashup with any music genre.


This Post Has 2 Comments

  1. Drew Ashworth

    Excellent explanation of harmonic mixing

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