Decibel Kit: Noise Dosimeter

Decibel Kit is a buy-once acoustic measurement kit that brings a sound level meter, spectrum analysis, a dosimeter and evidence reports together in one app. There is no subscription.

■ Live measuring is all free — and never stops
The dB meter, spectrum (FFT / RTA / octave bands / spectrogram), the NIOSH / OSHA dosimeter, the learning content and the camera dB overlay are free from the start, with no count or time limits.

■ One-time purchase, no subscription
"Pro" is yours forever after a single purchase. No monthly or yearly fees. We never take back a feature you have already unlocked. There is just one purchase screen, and you can close it anytime with the ×.

■ What Pro adds (keep it, prove it, export it)
• Save recordings and history (with audio)
• Export to PDF / CSV / WAV / HTML
• Save evidence photos and videos
• Save calibration profiles
• iCloud sync and Health integration
• Apple Pencil annotation, Before/After compare, trimming

■ Professional analysis
A / C / Z / B / ITU-R 468 weighting, Fast / Slow response, Leq, L10, L90, TWA, peak hold, 1/1 to 1/24 octave bands, adjustable ranges.

■ Numbers you can trust
Save device-specific calibration profiles for free, with a "±N dB" confidence range always on screen.

■ Strong as evidence
Photos and videos with dB, date/time and location burned in, your own notes, a tamper-evident SHA-256 hash, and a region-aware noise-regulation guide — all in one report. Great for neighbor, construction and workplace records.

■ Measure without stopping your music
Measure while music, AirPlay or Bluetooth keeps playing.

■ On iPhone, iPad and Mac
Universal. On large screens you can view the FFT / RTA / spectrogram side by side.

* This app provides hearing-safety guidance only and is not a medical device. It cannot be used for diagnosis or treatment.