Mixing in faster tracks to slower ones
I have cdj 850’s and am looking to mix a faster track after a slower one. (from 138 BPM to 140BPM) I am aware that you need to adjust the new track with the tempo slider so it is the same speed, but once mixed in, when do you adjust the tempo back to its correct BPM? Or do you leave it to play at the slower tempo?
how much slower are we talking about?
I would mix in at 138, and maybe somewhere in the break bump it back up to 140. Not really something that should stress you out so much. Just try it yourself.
Why bother bumping it up to its normal speed? If it doesn’t sound bad, just leave it at 138. Odds are a 2 BPM difference isn’t going to make much of a difference on the sound of the song.
With a hand on both pitch faders of each deck, I usually speed one up and slow one down to split the difference. If I mix out completely from the first track before a big breakdown, I’ll use that calm period in the breakdown to get it up to speed. This gives it a big impact and energy when the track’s rhythm kicks back in.
That’s if you’re really worried about it, which I wouldn’t be unless your dropping a house track into jungle or something.
Just slow the new track down to 138bpm and go with the flow. FWIW, Frankie bones said the best speed was 138 BPM for keeping people on the dance floor..
you can change the speed in the breakdown, hell i’ve done a 10 BPM bump in a breakdown, they’ll never notice
Cheers guys, thats what I’m doing at the moment, bumping the speed back up in the breakdown, but wasn’t sure whether this was the correct way of doing it. 
With that little of jump. I wouldn’t worry about it. As long as the song isn’t all chipmunks or tom waits when it’s not suppose to be, a couple of bpm here and there isn’t going to be noticeable to most listeners. I would just go with the flow. Keep it at 138bpm.