dB Halo: Sound Meter

Optimized for iPhone Duo. Built with the latest SDK, the app fills the entire inner display and automatically adjusts its layout whether the device is folded or open.

See how loud it is right now: a big live dB reading with minimum, average, maximum and peak, plus a time-stamped log of loud events. Measure noisy neighbors, a home workshop, a gym or a concert, then export a PDF report or CSV.
Estimate today’s noise exposure and remaining time against NIOSH or OSHA criteria, analyze sound in FFT, RTA and Spectrogram views, and let the Sleep Journal log snoring and other night sounds. Everything is processed on your device.

Choose A, C or Z weighting, connect an external microphone and save multiple calibration profiles for different setups. FFT Spectrum, RTA octave bands and Spectrogram share one live session. The on-device Sleep Journal recognizes and classifies snoring, breathing, speech, coughing, alarms, animal sounds, impacts, ambient sound and crying, then logs each event without saving raw microphone audio. Microphone audio is not saved by default; an AAC file is created only when you explicitly start a recording.

History keeps every saved session organized and ready to review. Export selected measurements as visual PDF reports or CSV data, export explicitly recorded AAC files, and burn dB overlays onto photos and videos. Export environmental audio levels to Apple Health, check Home and Lock Screen widgets, use App Intents and Shortcuts, and take standalone measurements on Apple Watch.

There is no account, no ads, no analytics, and no tracking. Processing stays on your devices.

Each general feature that produces a result includes three free uses. Spectrum, Noise Dose, and Sleep Journal each include one. A use counts only after a result is created; cancellations, permission denials, and failures do not count, and existing results remain readable. Lifetime Pro is one non-consumable in-app purchase: pay once, own it forever, with no subscription.

Measurements are estimates. dB Halo is not a certified professional sound level meter and does not replace medical advice or an occupational safety determination.

Optimized for iPhone Duo.