Booth Assist

Booth Assist listens through the microphone, picks out the rhythmic onsets in the music (the analysis is weighted toward kicks and the low end), and finds the tempo that best lines up with that pattern. When the estimate holds steady it locks, then keeps refining over a longer window: the second decimal only appears once it is actually meaningful.

In a loud or messy room:

• Point the phone toward a speaker or booth monitor, not the crowd. Crowd noise and nearby talking slow the lock.
• Sections with a clear, steady kick lock fastest; breakdowns and ambient intros take longer.
• Give it a few seconds and wait for the lock before trusting the decimals.
• Once you have the tempo, long-press TAP to pin the reading so it can't drift. Tapping TAP on the beat enters a tempo manually.
• Readings display in the 90 to 180 BPM window, so slower or faster music shows as its double or half (a 70 BPM track reads 140).

Related tempos: BPMs mathematically related to the detected one. 2:1 and 1:2 (double and half time) are on by default; 4:3, 3:4, 3:2 and 2:3 can be enabled in Settings. They're for planning transitions across tempo relationships - half-time and double-time blends, or polyrhythmic mixes that ride three against four. If the current track sits at 170, the 3:4 readout shows 127.5: the tempo a house record needs to lock into that blend.

The readout is an estimated A-weighted sound pressure level derived from the phone's microphone, and phone microphones vary from model to model. To calibrate: open Settings > Sound Level Meter, play steady music, compare the live reading against a reference meter, and adjust the calibration slider (up to ±15 dB) until they agree.

Two caveats. This is reference metering, not certified metering: fine for judging booth and room levels, not a substitute for a certified meter where hearing-safety rules or regulations are involved. And iPhone microphones saturate around 100 to 105 dB SPL - inside booth levels. When the input clips, the app flags it and the reading should be treated as a floor, not the actual level.

iPhone and iPad running iOS 16 / iPadOS 16 or later.

No. Audio is analyzed on the device in real time and is never stored or transmitted. The app makes no network connections at all. Details in the privacy policy.