The circle of fifths is a circle chart which shows the fifth interval relationships between any keys. There are more than one, but the simplest to read is the one below. As you can see, C major's perfect fifths are to the left and to the right of it. Also, you will notice the relative key, A minor, is below it in the inner circle.

A relative key is a scale that uses the same key signature as the principle. For example, the relative key of C major is A minor. Both use the same notes, just in different orders and arrangements. As you can imagine, these two scales mix together quite nicely as well. This gives you another option DJ mixing harmonically.

To get to the perfect 5th start with the C on the left and, including it, count to the right 5 semitones (steps) and you will get to G. G is the perfect 5th above of C. You can also start with the C on the right and count back 5 and get to F. F is the perfect 5th below C. Those are your best bets when harmonically mixing and moving from one key to another.

Let’s be honest. It’s 2017 and, if you’re a DJ, your sets had better be harmonically mixed. Mixed in Key is the perfect tool to help you in that endeavor. I have been a fan of this software since v.3. It’s now on v.8 and offers a lot more than just key detection. In this tutorial, I am going to not only show you how to get started in the program, but I am going to explain how and why harmonic DJ mixing works. In order to do that we need to understand a little about music theory in general. Don’t worry: it’s not too complicated and in the end you will feel better and be more prepared for your DJ career.