Groovelock: Key & BPM · iOS app
Groovelock listens to the music around you and shows its musical key and tempo on a harmonic mixing wheel — live, on your phone, without recording anything.
LOCK listens once, works out the key and the tempo, and freezes the result. Hold the phone toward the speaker and give it about 15 seconds of the track with the beat playing. Tap STOP to end, or tap the locked reading to analyse again.
LIVE keeps listening. When the track changes, the tempo reading dims, re-listens, and updates on its own; the key follows a few seconds later. Use it in the booth when you don't want to keep tapping.
Open Settings → Privacy & Security → Microphone and switch on Groovelock. The app only opens the microphone while LOCK or LIVE is running, and the audio never leaves your phone.
Some genres are ambiguous by nature — drum & bass, half-time hip-hop, dembow. Tap TEMPO under the buttons and pick the range you expect (for example 100–200 for drum & bass); the app will fold its reading into that range.
Through a room, over a phone microphone, the key can land on an adjacent wheel position (the relative major/minor or a fifth away). Get closer to the speaker, wait for a section with clear melody rather than just drums, and let LOCK hold for the full analysis before trusting it.
Found a track it gets wrong, or have an idea? Email feeltheenergysf@gmail.com — the track name and what the app showed is all we need.