The sync engine within Traktor DJ definitely isn’t perfect, but it’s almost certainly the best we’ve encountered within an iOS app.We tested it with a number of different genres with - as one would expect with any digital DJ software - mixed results.

House, techno and other relatively straightforward electronic genres the app handled almost flawlessly. On a few occasions the app struggled to identify the first beat of a bar correctly, but this is very easily fixed.

Tapping the grid edit icon to the right of the Sync button brings up the beat grid adjustment screen (pictured above.) In this window it’s a simple case of locating the opening beat of a bar and dragging it on to the correct beat marker with the stroke of a finger. Even midway through mixes, this is pretty simple and quick to rectify.

When we loaded a couple of electronic tracks with more complicated rhythms, there were a few instances where Traktor misjudged a song’s tempo. On the whole, these issues were easily fixed by using the Tap Mode to give the app a little helping hand getting into the correct ballpark.

Our only major issue came when we tried to load a vintage disco track with a live rhythm section and a beat that varied from bar to bar. Here Traktor DJ struggled to accurately guess a rough tempo, and the Tap Mode provided little help. Whilst usually a DJ could combat this problem by simply mixing by ear and nudging the track back in to time with either a jogwheel, controller or turntable, the app’s touchscreen interface and waveform design doesn’t particularly lend itself to this kind of mixing.

On the whole though, Traktor DJ’s sync functionality impressed us, and the way the app makes use of the touchscreen to adjust the beat grid is a definite winner. The way tracks are automatically dropped to make sure bars and beats are in sync makes mixing, if anything, so simple and easy that it's a little unsettling.