dB Halo: Decibel Sound Meter

dB Halo is a decibel meter and sound meter for everyday noise. See live dB with minimum, average, maximum and peak readings, a real-time spectrum and spectrogram, a time-stamped noise log and a sleep journal, with A, C or Z weighting and calibration profiles.

How loud is it, really? dB Halo is a decibel meter and sound meter for everyday noise. It shows live levels at a glance and keeps your measurements on your device.

Use it as a quick decibel meter in a home workshop, next to an HVAC rumble, on a gym floor or at a concert venue. The large Halo ring shows live dB with minimum, average, maximum and peak readings, plus a time-stamped event log. Choose A, C or Z weighting and save multiple calibration profiles.

Spectrum and spectrogram
Analyze one live session with a real-time FFT spectrum and a scrolling spectrogram. Switching views does not interrupt the measurement or the log. Dominant frequency, LAeq, sound pressure level, dynamic range, crest factor and sample rate are shown with plain explanations.

Noise Dose
Noise Dose estimates daily exposure against NIOSH or OSHA criteria and shows an estimate of the time remaining. It is for following trends, not for a professional determination.

Sleep Journal
The on-device Sleep Journal listens while you sleep, groups the sound level into quiet, comfortable, busy, loud and very loud zones, and logs each change with its time and dB level. It does not save raw microphone audio; an AAC file is created only when you explicitly start a recording.

History and export
History keeps every saved session organized and ready to review. Export selected decibel measurements as visual PDF reports or CSV data, and export the AAC files you recorded yourself.

Private by design
There is no account, no ads, no analytics and no tracking. Processing stays on your device.

Free uses and Pro
Each general feature that produces a result includes three free uses, and Spectrum, Noise Dose and Sleep Journal each include one. Pro is an in-app purchase that unlocks the full version without these limits.

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

Made for moments like these
• Checking how loud a neighbor, a road or a construction site really is
• Logging noise in your bedroom at night