Decibel: Sound Meter Pro

Decibel is a real sound-pressure-level meter — A, C, and Z weighted; LAeq, LAmax, LCpeak; statistical Ln (L10 / L50 / L90); OSHA 8-hour dose accumulator; permissible-exposure-time calculator. Per-iPhone-model offset corrections so readings track an actual SLM within ±2 dB across the 60–100 dB range.

Wear an Apple Watch on a job site, in a club, or in a stadium and watch the live SPL on your wrist. Cross 90 dB and the wrist buzzes. End the day with a PDF noise-exposure report you can hand to HR, your doctor, or a workers'-comp lawyer.

No microphone audio leaves the device. Ever. The DSP runs in milliseconds in Apple's Accelerate framework. No subscription "fleet platform," no ads.

WHAT'S MEASURED
• Live LAeq, LAmax and LCpeak — the full SLM toolkit
• A / C / Z frequency weighting (IEC 61672)
• Statistical L10 / L50 / L90 percentiles
• OSHA 90 dB(A) and NIOSH 85 dB(A) dose accumulators
• Permissible exposure time at the current level
• 1-second sliding LAeq and 125 ms Fast time-weighting
• Apple Watch live wrist meter with threshold haptics

EXPORT
• PDF dose report — printable, photographable, suitable for HR or workers'-comp documentation
• Per-second history chart inside the app

PRIVACY
• No microphone audio is ever recorded, stored, or transmitted
• No tracking SDKs. No analytics SDKs. No ads. No accounts.
• Zero network requests during measurement

WHO USES DECIBEL
• OSHA-aware blue-collar workers (construction, manufacturing, oil & gas)
• Live-sound engineers, DJs, musicians, and stage crew
• Parents monitoring kids' bedroom and daycare noise levels
• Wedding / party planners staying within sound-level limits
• Older adults wanting quantitative awareness of environments

SUBSCRIPTIONS
• Free: live LAeq (A-weighting), large-digit display, 7-day history
• Pro ($3.99/mo or $24.99/yr · 7-day free trial): C/Z weighting, LAmax/LCpeak/Ln, OSHA & NIOSH dose, PDF reports, Apple Watch live meter, unlimited history
• Pro+ ($9.99/mo or $59.99/yr · 14-day free trial): manual ±5 dB calibration trim, per-microphone profiles
Trial: 7 days for Pro, 14 days for Pro+, one trial per Apple ID.

CALIBRATION DISCLAIMER
iPhone microphones are not Class 1 / Class 2 certified hardware. Decibel readings are intended for personal awareness and screening, not legal regulatory evidence. For legal compliance use a certified meter calibrated by an accredited lab.

Privacy: https://leexuanxuan95-dev.github.io/decibel/privacy.html
Terms: https://leexuanxuan95-dev.github.io/decibel/eula.html
Support: [email protected]