You want a "loop shift" (like serato) function.
You can do it with cdj 2000nxs2, xdj 700, xdj 1000 mk2 using the addon controller DDJ XP1.
- Enter a loop
- Change to "Beat Jump" mode
- Use one of pre defined jumps to jump forwards and backwards
- Try to learn how to use quantize to achieve a perfect jump
In my personal experience, to do what you want:
- Create a loop of 4 bars
- Change to beat loop while playing this loop
- Backwards beat jump 16 beats (4 bars) at the start of desired loop (you will need to walk 1 loop at least)
This trick needs some attention, it is a workaround because the beat loop function will move the actual playtime.
In serato the "loop shift" moves the loop but you still at the current time, so you can create and move a loop whenever you need.