Digital DJ Tips reader Richard writes: "I have a live recording where the drum tempo drifts all over the place. I'm trying to mix an acapella into it (which has a consistent tempo) using Virtual DJ, but the tracks drift apart (in both directions) and it's impossible to keep them in sync. Is there some software which can take my live recording and process it to make the tempo consistent?"
Digital DJ Tips says:
Yes, there is. The most "famous" way to do this is in Ableton Live. You "warp" the track; that means dropping beat markers all the way through it that show where the real beats drop, and then Ableton can make the track tempo uniform by applying complex beat correction algorithms. DJs often do this at the start and end of, say, old disco tunes, which makes it easier for them to mix with them, while still retaining the "groove" that having what is usually a live drummer (hence the irregularities in tempo) lends to the track. In your case, if you want to mix an acapella over it, you'd have to do it all of the way through.
Other DJ software can do this, though, too: Serato has "elastic beatgridding" that achieves much the same thing, and MixVibes also has an excellent take on it too. Virtual DJ (in common with Traktor), unfortunately doesn't.
The other way to do it is simply to "ride" the tempo using your jogwheels. By slowing down or speeding up the acapella in the "quiet" parts (ie the bits "between the vocals") you can get it there or thereabouts. It's how DJs always used to do it before digital... Hope that helps.
How do you get around DJing with tracks that have an uneven tempo? Please share your thoughts in the comments.