Beginners' Guide To Keylocking

traktor yellow note

The yellow musical note in Traktor Pro 2 that tells you your track is "keylocked" - but what are the dos and don'ts of keylocking?

Several readers have asked about keylocking recently. This is typical, from Max in Serbia/Montenegro: "I know what keylock does and how it works but I (and a lot of other DJs) have no idea when I am supposed to use it. If there are certain guidelines or 'rules', it would be awesome if you helped us get educated about that because there isn't much info about it on the net."

If you're one of those DJs who always looks at that little "keylock" button but feels unsure about how or when to use it, this is for you:

What is keylock?
Keylock fixes the pitch of a tune while letting you alter the tempo, stopping the tune getting deeper and deeper as you slow it down, and stopping it getting whinier and higher-pitched as you speed it up.

What's the point of it?
When you beatmatch two tunes, if one of them is sped up or slowed down too much, it might sound "wrong". This returns it to its original pitch while still letting you play it faster or slower.

How does it do it?
It uses your computer as a digital sampler, processing and resampling the tune on the fly and feeding it back with its pitch returned to how it is when played at the correct speed.

So I should just leave it switched on then?
Some DJs do, but the problem is that the work needed to "return" the tune to its original pitch can degrade the sound quality. It happens most when you deviate a long way from the original tempo, so keylock works best when you're mixing tunes that are close to their original tempos - say, no more than + or - 6% - and with simpler material. Use your ears to judge.

What's it got to do with "harmonic mixing"?
Harmonic mixing, aided by key-tagging software such as Mixed in Key, is when you mix together tunes that are in the same or related musical keys, for smoother, more musical sets. Every tune has a musical key, but when you alter its speed, as we've seen, the pitch and thus the key alter. So if a tune is in the key of C, and you move it up in tempo, it is no longer in C. It may be in C#, or D, or E etc - or just as kiley, between two of these keys. Thus if you were mixing it with another tunes in C, it would sound wrong. Keylock "returns" it to its usual key, making this kind of mixing easier.

So should I use it?
If you're doing harmonic mixing, broadly: yes. If you're mixing music that sounds too high or low because you're deviating from its original pitch too much: try it, but keep an ear on the quality. One tip here is to use it to mix, but as soon as you've mixed the tune in, slowly return its tempo to 0% using the tempo slider, then turn keylock off - this will return the sound quality to 100% but still allow you to do the mix you wanted.

Can you do harmonic mixing without keylock?
Yes, but it's much harder. Best is to use all tunes around the same BPM, but also, every time you add or subtract 6% of a tune's tempo, you move up or down one semitone (note), which also changes the key to one higher or lower. So a tune in C moved down 6% is now in B. Knowing this, even vinyl DJs can mix in key, as long as they know they keys and BPMs of all of their tunes.

Next week, we'll look more closely at harmonic mixing, so if this is something you've always wanted to have a go at, play with keylock in the meantime and we'll get you going on harmonic mixing next Friday.

Do you use keylock? What are your experiences with keylock and sound quality? Let us know your thoughts in the comments.

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  1. Gui Amado says:

    I use Harmonic Mixing a LOT. So I just leave Keylock on.

    • Phil Morse says:

      In that case you should be careful with sound quality as it certainly reduces the quality, sometimes drastically, if this is your tactic.

      • Gui Amado says:

        How should I be careful? There is any workaround on this "quality loss"?

        • Phil Morse says:

          Yes there is. 1) Try to mix tunes with similar BPMs (keylock doesn't work as hard with these). 2 Use your ears - the more complicated a tune, the lower the quality tends to be, but you should listen critically. 3) Move the pitch slow manually back to 0% once you've mixed a tune in - at 0% the keylock can be turned off without concern. Just remember to turn it on again when you next use that deck for key mixing!

      • I'm looking into MIK for the first time, but haven't gotten practical about it yet. I always select a BPM range per mix/set and stick with it. Say my first track is 127.0 BPM but I want to play a faster set, I'll push this to 132.0 and select my tracks within a 127-135 BPM range. I think I'm right in assuming I could push that range even further, or at least widen my choice of track selection across a few more genres, by mixing in key? I'm paranoid about mixing tracks outside of the mentioned 8bpm range.

    • Phil Morse says:

      " I think I’m right in assuming I could push that range even further, or at least widen my choice of track selection across a few more genres, by mixing in key? I’m paranoid about mixing tracks outside of the mentioned 8bpm range." - Yes you could, but use your ears! That's what's most important.

  2. Thanks for these details on the Keylock function. Can't wait for the next topic about Harmonic Mixing!

  3. Great stuff here, thanks for the article.

  4. Harmonic mixing is very good for some styles, but not so much in others. A nice progressive trance set is perfect for harmonic, but a hard dance set sounds better without, IMO.

    Also, a whole (let's say trance again) set of harmonic mixes isn't something I'm down with. It starts to sound a bit flat and boring after a while as there's no real direction change. You can really kick things up a notch by completely changing the key, especially if going into something with a tougher bassline...

    • I don't use the key lock but I know what you mean about a flat sounding boring set. I'm only a beginner and I've listened to some of my recordings and though that I may as well have been playing the first track for 2 hours on a loop with a couple of beatmashes. I prefer trying to incorporate some kind of variation which includes changing the pitch. I just do it by ear and selection.

      OK, when I say I don't use the key lock that is not totally true. I have the key lock constantly on on Deck A. But because I'm not 100% sure what 'keyed' mixing is all about I think it's safe to assume that I don't use it.

    • You can kick things up using harmonic mixing... you don't have to stay in the same key always. Just go up a fifth (+1 in the camelot notation) and you will be going higher while avoiding key clashing =)

  5. I only use keylock when I can see vocals and/or sounds in a tune slightly sped up sound strange. When I made that recent old school mix and used "Good Beat" by Deee-Lite, I noticed Lady Miss Kier sounded strange when slightly sped up. Keylock sounded good.

    Pretty much all the time though I leave it off, since I'd rather have pitch get higher as opposed to stuttery sound.

  6. When mixing house and techno, key lock is great. My tunes BPMs generally are between 118 - 130. I tend to choose a BPM around 124 or so for my whole set or mix, though sometimes I will start at a slower tempo and gradually increase it throughout a set. Regardless, for this type of material, I've never noticed any issues with sound quality - largely due to the fact that I'm not doing radical changes in pitch. You can also use the key knob in Traktor to get your tunes to be in the same key on the fly, but I rarely do this in practice. I don't use mixed in key but you can tell when the chord changes or other musical elements of a tune match or not. Anyway key lock is one of the most amazing aspects of digital DJ'ing.

    • I also prefer to select tracks from a particular bpm range per set. If I'm playing for a couple of hours or more then I will also, at some point, change the tempo.

  7. and turn it of for scratching since
    altering the pitch is a great way to
    ad musicality.

  8. Keylock sounds a lot better than no keylock, if you plan to return the speed to 100% after doing the beatmatched mix. Otherwise, you'll hear the pitch drift, and that sounds pretty horrible.

    Besides, any DJ software worth its salt should automatically turn keylock off when the tempo is playing at 100%. I know Jackson DJ, a software from 2003 with a rather low quality timestretcher (or keylocker, same thing), did, as you could hear the quality clearly improve when the tempo was adjusted to 100%.

  9. DJ Sir Andy says:

    The quality of the time-stretching algorithm of your preferred DJ software also factors in whether or not to use keylock excessively in your mixing. If you have a good algorithm that doesn't leave too many digital artifacts nor degrades the sound quality of the track you can venture into the +/- 20% pitch range and still mix harmonically without original vibe of the track suffering too much. Good for transitioning from hip-hop into electro or house and using a big tempo change to move up two slots on the Camelot wheel to bring up the energy significantly IMHO.

  10. Good post! Pitch adjustment (including keylock) works better with some styles of music than others, because some musical waveforms are more complex than others.

    For example, music that is heavily percussion, such as freestyle, suffers more than others with pitch adjustment because percussion waveforms are more complex than steady tones. Complex music may tend to echo more noticeably than other styles.

    Advanced harmonic mixing styles, such as energy-boosting modulation mixes and BPM "region shifting," are covered at

    If you would like free trial access to our work-in-progress online harmonic mixing database, please email

    • I'll get a little more specific and mention that keylock doesn't sound very good with certain kinds of instruments.

      In my experience, broad bass sounds or anything with a lot of existing distortion will be largely ok, but some delicate and transient sounds, like xylophones and sometimes crash cymbals, can shows signs of artifacting when key lock is turned on, even at low pitch settings.

      As mentioned by somebody else, it'll depend on your software's algorithms, and as the article states, use your ears.

      • Phil Morse says:

        All true. It's funny that sometimes a track you really think ought to be fine sounds awful, even just slightly off pitch, whereas others seem to cope with it just fine.

  11. DJ Gerard says:

    Since keylock has come into play with digital DJ workstations as opposed to turntables or older cd players I have always used keylock. I never much cared or noticed a difference unless I adjusted the tempo, keylock sounded less noticeable if I was changing the speed of a track of course.
    I can say this, I have played locally for over 15 years and only one patron who happens to be a musician blessed with perfect pitch hearing ever complained. He would come to my booth and ask me to put the record back to zero % pitch because I was 'killing him" and he couldn't take it. Also after taking a music 101 lesson recently I understand the affects of key in a song. I for one will leave keylock on (todays cpu can handle the math) and mix at the breaks. No harmonic mixing here, leave that to the mashups.

    • About the same here. Traktor Pro 2's keylock is pretty impressive, I can push 140 BPM music up to 170 BPM at it sounds pretty much ok. Maybe you can only notice the sounds of keylock in less aggressive music, maybe TP2 is magic. I just leave keylock on so I never forget it and I concentrate on mixing.

  12. Aidan Johnson says:

    Always thought keylock sounded ok... until I got onto a 3K PA at a free party. Yuk... switched it off straight away and had to do the +/-6% thing in my head, couldn't be bothered by the end as I was too.. um... let's say drunk. :)

  13. Well explained. I used to do the same when bringing in a faster song. I would put on keylock reduce the tempo a bit and after the transition slowly restore it to original tempo.

  14. With Keylock on, avoid changes at + or - 1.74% and you won't lose quality. At least with Traktor, this holds true.

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