Key Mixing in DJ: Musical Keys Made Easy for DJs

Mixing in key is something a new DJ will gravitate towards when they discover it. And they should. Songs sharing a key, or whose keys are closely related, just sound like they go together. Why is that? This article will delve into some substantial music theory – a turnoff for some, perhaps, but vitally important to understanding what exactly is going on here. Don’t worry – it won’t be too intense, and I will walk you through it so that those without a background in music theory can follow along and understand. 

Now, let’s explore musical keys for DJs: What are the rules? What are the limits? And can those rules and limits be broken?

Contents:

• A Crash Course in Keys
  • Why Do We Match Keys?
  • Which Keys Go Together
• Camelot Notation
• The Rules for Key Mixing: Can They Be Bent or Broken?
• Advanced Key Mixing
  • Pedal Point
  • Superimposition
• The Golden Rule

A Crash Course in Keys

A musical key describes the tonal center of a piece of music. Essentially, there are a total of twelve possible notes in western music (there are more notes called microtones that exist between these twelve notes, but they are not recognized in the western musical system). This cycle of twelve notes repeats itself above and below in octaves. It can also be arranged into a fundamental harmonic structure relative to themselves. This fundamental harmonic structure is called the major scale.

A major scale consists of seven notes. The rest of the twelve notes exist between the seven notes of the scale. Each of the seven notes can be expanded upon by stacking every other subsequent note on top of it, creating chords. Do this six times, and you will have stacked each note of the scale over two octaves.

Here is where the term key comes in – in order to create this overarching harmonic structure out of the twelve available notes, you need to establish the center, or root, note. A musical key defines that center note.

This twelve note system has its roots in western european classical music, and has been passed down and stylistically diversified over the centuries. Virtually every style of music you come across in the western world – from rock to pop to jazz to house and techno – is based on this system.

Why Do We Match Keys?

In DJ, we key-match tracks because they share the same – or at least a closely related – fundamental harmonic structure. This means songs in the same key have the same tonal center and utilize the same set of notes. Thus, they fit together harmonically like a hand in a glove, allowing for pleasing, fluid transitions.

Musical keys have been notated in the traditional format for hundreds of years. This is simply the name of the center (root) note, sometimes followed by the lowercase letter “m.” 

The “m” stands for minor, and all it means is that the tonal center is not the first note in the relevant major scale sequence, but the sixth. This is why DJ software will suggest tracks in Am if you’re playing a track in C – they are actually based on the same set of notes in the same harmonic structure. We call this a relative minor.

Which Keys Go Together?

In music theory, we have a special wheel – the Circle of Fifths. This sequence, based on the overtone series (which lands outside the scope of this article, but is quite interesting), describes a sequential method in which all twelve musical keys can be derived by adjusting one note in the structure at a time. On this circle, adjacent keys share all notes but one. The further apart the keys are, the fewer notes they have in common. This is why distantly related keys sound so bad together – they’re based on completely different sets of notes!

Minor keys work exactly the same way. They may have very different vibes, but a minor key and its relative major key are exactly the same.

As the name implies, the circle goes around the twelve notes in fifths. This means you count five scale tones from where you are to arrive at the next key. So, C > G > D > A… etcetera. This is a sequence musicians internalize very early on, as we refer to it all the time. So it’s easy for us to think “we’re in Bb; let’s move to F.” But for the uninitiated, having to count your way around the circle can be tedious and frustrating. This is where a company called Mixed In Key comes in.

Enter Camelot

Mixed In Key developed software for identifying keys in music. Their objective was to bridge the theory gap for DJs without a traditional musical background. Camelot notation was developed by Mixed In Key in order to simplify the process of selecting tracks based on key, and to make the process accessible to DJs who lack a background in music theory. It’s clever how they did it – really it’s quite simple.

If you know the Camelot system, you know the Camelot wheel. The Camelot wheel is the circle of fifths, but instead of an esoteric sequence of letters, the keys are numbered clockwise 1 – 12. The outside sequence is notated as B (major keys), and the inner sequence is notated as A (minor keys). As an additional visual reference, the circle follows a color pattern, denoting how similar keys sound based on the similarity of their colors.

Finally – no more counting fifths. No more relative majors and minors. Just 1 – 12, A or B. It was a game-changer for DJs everywhere.

Nowadays, all of our DJ software accommodates the Camelot system. However, some of us with a musical background choose to stick with traditional key notation. I prefer traditional notation, but that’s just because I’ve been a guitarist and bassist for 20+ years, and I had internalized the circle of fifths long ago. I just think that way. There’s really no benefit to using traditional over Camelot, or vice-versa.

What Are the Rules for Key Mixing? Can They Be Bent or Broken?

The rules for key mixing go like this: you can mix tracks in the same key, the current key’s relative major or minor, or adjacent keys (perfect fourth or perfect fifth) without fear of harmonic dissonance. In Camelot terms, you can mix the same number/same letter, the same number/different letter, or adjacent numbers/same letter.

But there’s more to it than that. 

In reality, you can mix any key with any other key. You can to do whatever you want to do. The trick is understanding the dissonance you may be invoking.

For example, you can transition between keys separated by a space on the wheel and still be in business. It won’t be as harmonically cohesive, but it has a distinct sound to it. Bands do it all the time – it’s called a whole-step shift. You can also try transitioning between keys separated by two spaces on the wheel. Now, we start getting into more audibly jarring territory. The important consideration when mixing disparate keys is that the further apart they get, the worse they will sound when their harmonic content overlaps. The solution for mixing disparate keys, then, is to keep their harmonic content separated.

You can easily do this by waiting for and/or looping a section from either song with minimal harmonic content. Little pitched bloops or chirps are okay – I’m talking about distinctive bass lines, obvious chords/ pitched pads, and prominent melodies.

Looping a harmonically ambiguous passage allows the other song’s harmonic content to dominate the sound without competition. The next step is spotting your mix point – the point where you will cut the outgoing track’s harmonic content and allow the new track’s harmonic content to take over. This is an effective technique for key changes, and can be used to transition to any new key. Introducing a short passage with no harmonic content (e.g. only drums) is also an effective palate cleanser for establishing a new key. For some genres, cut mixing can also be an effective option. Just bear in mind that the previous point still applies – the further apart the keys are, the more jarring the key change will be.

Advanced Key Mixing

Music theory isn’t a collection of hard rules. They’re more a set of common conventions and adamant suggestions. There is always a loophole, technique, or context for any combination of notes to “work,” and there’s always notation to describe it.

Pedal Points

One technique is to employ pedal points. A pedal point refers to a single note, typically in the bass, that sustains or repeats itself as the harmonies above it progress and change. So if you have a track or passage with a single note line (not an uncommon thing in electronic genres), you can leverage that by introducing new harmonic content from the incoming song as you cut the harmonic content from the old song, all the while maintaining the monotone/ostinato bass line. 

Using this technique will sound odd, but that odd feeling will dissipate with repetition. In music, repetition reinforces, so after a few loops of the new key over the old bass line, the ear will accept it as the “new normal” until you cut the old bass and replace it with the new bass – completing the key change.

Superimposition

Another technique – mostly a jazz thing – is superimposition. This is when a composer or performer purposely writes disparate keys into a piece or passage. It creates deliberate, acute tension caused by the harmonic dissonance between the competing keys. While a DJ isn’t a composer, they most certainly are performers. They create new passages by combining existing compositions on the fly. In effect, they can employ the same technique – just less surgically and less focused. Looping is your friend here because shorter passages can be repeated with greater frequency. And since repetition reinforces, this can help your dissonant mix “work” better.

Now, just because there’s a word for it in music theory doesn’t mean it will sound good. Superimposing keys sounds very dissonant and really weird, even in the best examples. It may still sound “wrong.” In the context of a club setting, this type of thing may not work, even if it is intentional. The dissonance and tension may be too much for the audience, and you might lose the dance floor. In the end, you have to know your audience and play to the crowd.

The Golden Rule of Music: If It Sounds Good, It Is Good

In the end, the Golden Rule is the law of the land. You can do anything and everything as long as it sounds cool. Key mixing is no exception. However, it is crucial to understand harmonic dissonance in order to avoid it – or effectively employ it – in your mixes. 

Key changes are a good thing – they add flavor and spice to what would otherwise be a bland, monotone mix. Electronic music is repetitive enough; use all the tools at your disposal to spice things up.

That includes jumping keys. Just be sure to jump responsibly.

Until next time,

AudioMunk

Looking for more DJ-centric performance insights? Check out these Audiomunk articles:
Phrase Mixing
Gain Staging for DJs
Why to Avoid Going Into the Red