Polyrhythmic Loop Calculator

BPM:
Ratio: /

3 x 120 bpm = 4 x 160 bpm

4 x 120 bpm = 3 x 90 bpm

Calculates BPM/beat length ratios for creating polyrhythmic loops/blends. i.e, a 3 bar loop over a 4 bar loop for example.
3 beats of 120 bpm and 4 beats of 160 bpm are both 1.5 seconds long, so when looped the 1st beat of each loop should sync up. Whether the rest of the loop sounds good is up to you :)

You can do this calculation manually with the following algebra:

        bpm1 * beat2 / beat1 = bpm2

CDJ/XDJ's make it easy to auto loop even numbered beat lengths on the fly, but you need to get creative to make perfect odd beat length loops.

Use 3 repeats of a 1 beat auto loop instead of a 3 beat loop
Use 4 repeats of a 3/4 slip loop instead of a 3 beat loop
A shorter loop length on the even numbered beat can also make things easier, for example using a 2 beat loop instead of a 4 beat loop to avoid a snare on the 3rd beat that clashes with the triplets
In Rekordbox use Quantize and Active Loop to set a perfect 3 (or 6, 9, etc.) beat loop that will automatically trigger at your mix out point
Or make an edit of the track: use stem separation to remove elements that clash with the blend, cycle through different 3 beat loops, add tempo FX to emphasize the BPM shift, add little polyrhythmic flourishes to the start of the track to tease the tempo change
For mixing in a track, use quantize and manual loop in/out on CDJ/XDJ to create a perfect 3 beat loop on the fly
Using tempo FX on one or both tracks can help smooth things over

Made by DJ Sad Gay Techno