doppio: BPM for DJs

A living metronome for DJs — not a calculator. See your track's tempo and its half/double partner as two overlapping rhythms. Read the relationship at a glance — no maths mid-mix. • Swipe to set the BPM • Tap to flip ×½ / ×2 • Second finger = decimal-fine • Haptic tick on every beat • 5 beat visuals · 12 themes · shake to change No account. No ads. No tracking. Just the number — rock-steady, glanceable in a dark booth.