Mixing in key is an important factor when performing, depending on the type of music being played. Tracks that have harmonies and melodies in a specific key don't sound good when blended with similar tracks not in the same key. Fortunately, with the invention of key notation software, mixing in key, or harmonic mixing, has never been easier. Although its benefits definitely outweigh its cons its important to be aware of some traps.
There are currently three main key notation software packages available for DJs, which include Mixed In Key, Rapid Evolution, and Beatunes. Although key notation software can do more than just key your music, its main job is to analyze your files and let you know what key your tracks are in. In most cases, mixing in key is a very important part of a successful performance. Mixing out of key can be as painful to the ear as fingernails on a chalkboard and is not a good look when your trying to rock the dance floor.
Mixed In Key and Rapid Evolution give you the option to use what is called the Camelot System to differentiate the key of the tracks. This is really helpful for those of us who don't know much about music theory and who aren't familiar with which keys sound good together. Rather than relying on a lettered key notation that you see in traditional music scores, it uses a number system. With this system you can see what tracks will be in key together at a glance. I won't go into complete details about how it works but, in short, the Camelot wheel's keys are represented like a clock. The inside circle represents minor keys (A) and the outside circle represents major keys (B). Once your files have been analyzed, a key notation, or number, is added to the track representing the key it is in. You can then choose another track that has the same number or one that has a number that proceeds or follows it. For example, if you are playing a track with the key notation of 3A you can mix another track into it that is also in 3A or you can mix a track that is in 2A or 4A. All three of these options ensures that you are staying in key and that your mixes sound good. For more information on the Camelot wheel, and in particular Mixed In Key software, click --> here.
I didn't need to mix in key for most of my early DJ career because I was playing drum and bass, and that was more about sub bass lines and single stabs and not so much about melodies and harmonies. It wasn't until I started getting into the more atmospheric and melody-based dnb that I started to notice the flaw of mixing out of key. Yuck! Fortunately for me, key notation software had just hit the market when I started enjoying melodies and harmonies in my music.
I remember seeing a friend, back in the day, keying all of his tracks using a pitch pipe. Once he found the key of the track he would then write it on the sleeve of the vinyl record. This was very time consuming to say the least, which brings me to the first, and what I think is the biggest benefit of using key notation software... not needing to spend your valuable time keying tracks with a pitch pipe.
Key notation software adds the key information directly to the id3 tag of the file in seconds and that information will, in turn, show up in the DJ program. Mixed In Key takes it even further by adding a number from 1-10 to a chosen part of the id3 tag which indicates the energy level of the track. Number 1 being the lowest energy and 10 being the most energetic tracks. This is really helpful when searching through your playlist of new songs to find the right track for your current dance floor.
Another huge benefit is when you are DJing with someone else that is playing tracks you aren't familiar with. Being able to glance over and check the key of their track cuts down on time spent trying to find a track in your library that may sound good with it. There is nothing more frustrating than DJing with someone who hasn't keyed their files and are playing a melodic track that you now need to mix into. Having yours, and your DJ partner's files keyed, cuts down on the time you spend looking at your computer and/or auditioning tracks to find the perfect song. Although you might not find the "perfect" track at least the track you do drop will be in tune.
Using key notation information when practicing can also be a huge help. No longer are the days of having to match up good sounding mixes by painstakingly playing every piece of vinyl over and over again. Most of the time two tracks being out of key is what ensures you will never play those two tracks together. Referencing the key information from the get-go helps narrow down the various possibilities, which saves you loads of time, but be aware that this is where the "traps" come into play.
If you are like me, and all my friends that have found the glory of key notation software, the first thing you'll do is organize your library by key and start playing your tracks from top to bottom. Amazed at the beauty of your seamless mixes you'll be immediately sold on harmonic mixing BUT you will also, unknowingly, start to succumb to the alluring trap of its ease. Be aware, its easy to start relying on key notation information to narrow down your awesome mixes. Yes, your mixes will be in key, but you will more than likely miss out on some, not so obvious, awesome mixes. For example, just because a track may be keyed with 10A doesn't mean that it won't sound good with a track keyed in 2B. If you completely rely on key notation information you won't attempt to play such tracks together and, unfortunately, miss out on great mixes that could elevate your set to god level.
Having such a great tool in your pocket can also make you very lazy when it comes to spending time getting to know your tracks. As DJs, our job is to know the perfect track to play at the perfect time. This requires us to really know the tracks in our arsenal. There is nothing that can take the place of simply taking the time to listen to your music. Mixing in key is half the battle, and it may get you through the set with a happy crowd, but it won't ever take the place of solid music choices that drives your crowd into a frenzy.
Something else to be aware of, is where in the file you add the key notation. Some programs, including Scratch Live, rely on filename information to see where the imported files are stored on your hard drive. Although you can choose to write the key information into the actual filename within the preferences of the key notation software, by doing so, the DJ application you use may no longer be able to locate the file. I would suggest choosing to have the key notation software add it to the "initial key" part of the tag. You are then able to see the key information in the "key" field in your DJ application. If the program you are using does not have a key column I would suggest adding the key notation to the comment field.
Using key notation information is a powerful tool, just as using loops, cue points, and effects are. Its intended to aid you in your job as a DJ, not dictate the direction of your set. A good suggestion was told to me by my good friend and co-worker, Shaun Whitcher, which is to first create a set list without looking at the key notation information. Get to know your music, place your tracks in the order you think they would play well, using your DJ Jedi mind, and then look at the key notation as a reference. From there, if two songs have keys that visually don't look like they will go together, have a play with them and see if they can still work. You may just find your mind gets blown by how great it sounds!
Key notation software is now a main stay for digital music performers. If you haven't started utilizing key notation information in your performances I highly suggest you start. As long as you're aware of the potential pitfalls you'll be that much closer to attaining perfect sets.