Which Is The Best DJ Key Detection Software?

Phil Morse | Founder & Tutor
Read time: 4 mins
Last updated 29 March, 2022

Mixing in key – making sure your tracks are compatible harmonically when you DJ – is one of the big areas of DJing that has been made easier by digital DJing. But which key detection is best right now That’s what we’ll find out in this article.

Why this is important

The combination of being able to know the key of a song, “lock” that key even when changing tempo, and even have your software suggest potential matching tracks, has been a game-changer for DJs in recent years.

But just as when your software guesses your tracks’ BPMs wrong, no amount of hitting the “beat sync” button is going to save your mix, if the key detection is incorrect, you’ll have a similar problem too.

Trained musicians can quickly figure out the key of a piece of music – some can even do so without resorting to an instrument. DJs wanting to mix in key “back in the day” had to do this, too. (I remember doing so with a piano keyboard and some rudimentary chord knowledge, gained from my training as a guitarist.)

The arrival of key detection software

Even as recently as a few years ago, DJ software didn’t even have key detection built into it. But luckily there was a piece of software called Mixed In Key, a standalone key detection app, to add this information to MP3s. This information could then be “seen” by DJ software, enabling DJs to mix in key.

Move forward to today, though, and nearly all DJ software has key sync built-in. Mixed in Key is still around. And there are other alternatives, free and paid for, either standalone or part of other music-related apps.

So the big question for DJs is: Should you use Mixed In Key, the “industry standard”? Or should you just rely on the key detection built in to your DJ software? Or something else?

So… which software is best?

So first let’s look at the “best” key detection software options we have today. This graph was done in 2020 by Reddit contributor bascurtiz, who we’ve known here at Digital DJ Tips for a long time, and to whom we credit this research fully. I won’t go into his methodologies, but trust me – he has been thorough. (You can dive deeper if you like on the original Reddit thread.)

Best keymixing software 2020

So you can see that according to this research, the best key detection here is with Mixed In Key (76.5%), but that of the big DJ software platforms, Traktor (73.8%) and Rekordbox (69.2%) are not so far behind. And kudos to Hercules’ DJ software, DJUCED, firmly in the number two spot!

Engine Prime (62.5%), Serato DJ Pro (60.6%) and Algoriddim’s djay Pro (61.6%) are a bit behind the leaders, with Virtual DJ (42.7%) at the back of the pack.

How to act on this info

So two questions arise:

  • If even the best of the best (Mixed In Key, 76.5%) guesses one in four tracks “wrong”, should you be relying on key detection apps/algorithms at all?
  • And what should you do if you use one of the “lesser performing” DJ apps?

So first, let’s hear from Yakov, the maker of Mixed in Key:

“If you give the same song to two human musicians, they will agree with each other 75% of the time. If you give the same song to Mixed In Key and a musician, they will agree with each other 75% of the time too.

“Mixed In Key and human = 75% agreement, Human and human = 75% agreement. They are the same. There is no such thing as 100% agreement because humans can’t even agree with each other.”

(So what does this mean if your software isn’t in the top of the pack? Maybe you shouldn’t worry so much. For instance, by this calculation, Serato is “actually right” 80% of the time, compared to humans.)

Learn how to mix in key with us: How To Master Keymixing

But second, we come to the most important point:

Deafly following what key detection software tells you about your tracks is a bad idea!

You may not have pitch perfect hearing, or be a musician, but you still have ears, and you can still hear whether or not two tracks work well together. We all can.

Just as we can hear if the timing is out, we can hear if the key is out too. Listen to this. It is Toto’s “Africa”, with both of those things – timing and key – deliberately one note/one beat out. I encourage you to listen as far as the chorus, for the full horror of this:

Silly, I know, but it proves the point: We all intrinsically know what sounds right – and what doesn’t. As DJs, we need to call this one – if it doesn’t work in your headphones, don’t inflict it upon your audiences.

Once you allow yourself to trust your ears, who cares if the results are “out” sometimes? If it sounds rubbish in your headphones, move on and try something else. No harm done.

Read this next: The Ultimate Guide To Keymixing For DJs

Why consistency is, ahem, key

My final point is this: It is always better to stick to the same key detection, rather than chopping and changing. If you use Mixed In Key, continue to use Mixed In Key. If you are a new Serato user and have started with their key detection, stick with it. And so on.

Remember, this is art as well as science, and if your software gets it “wrong” consistently, that’s better than having random errors among many key detection systems in your collection.

And I am sure the makers of the lesser-performing apps in this test will have convincing arguments as to why they are just as trustworthy as the winners!

• Thanks to bascurtiz for doing this research – check the full research out over on Reddit, and again, check out our harmonic mixing training here.

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