Cadenzo

A metronome tells you the tempo. Cadenzo tells you what to practise, at which tempo, and for how long — and then beats the time through your wrist so your ears stay free for the instrument.

Two things do the work. A three-up, one-down tempo ladder: three clean repetitions and the tempo goes up, one slip and it comes down. That rule settles around a 79 percent success rate, which is where you learn fastest. And a practice planner that divides the minutes you have by what you are forgetting quickest, using a retention curve per piece that lengthens every time you come back to it.

WHAT IT DOES

• Haptic beat from 30 to 260 bpm, with an accent on one and a weaker accent on the subdivision
• Time signatures 2/4, 3/4, 4/4 and 6/8, subdivided in quarters, eighths, triplets or sixteenths
• A tempo ladder that raises and lowers itself, with the step shrinking as you near your limit
• Session planner: tell it how long you have, it tells you how to spend it and why
• A forgetting bar per piece, so you can see what is draining
• Tap tempo, a session log and a tempo trend per piece
• Five languages, a glance with your next session, and a running session that survives closing the app

WHAT IT NEEDS

• A watch that can vibrate. Everything is worked out on the watch: no phone, no account, no internet
• The beat runs off the system clock and corrects its own drift, so it stays tight over long sessions