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.