YayaCheetah

Whether you are trying to master polyrhythms or learn a complex rudimental piece, this app will accelerate your progress. It has an intuitive user interface and loads of features. Programming complex patterns is fast and easy. The only time that I could not figure out how to achieve a particular goal, I received a personal email from the developer with the solution in just hours after asking the question. Every musician needs this tool in their arsenal.

The app can be a bit wonky with odd time signatures, but it otherwise does a fairly amazing job without the need for extra trigger hardware. I have used it to learn how my emotions impact my tendencies to speed up or slow down. I also use it to show bandmates where their perception of time is off (“No, in fact we did not speed up. We were +/- 1 bpm the entire time. Have a look at the data.”)