NoiseLedger vs Frequency Analyzer

NoiseLedger is a privacy-first decibel meter and noise log for iPhone. Measure sound levels in real time, run overnight recordings, and export professional reports — with no ads, no account, no subscription, and no cloud. MEASURE WITH CONFIDENCE • Real-time dB with FAST/SLOW response, MIN / Leq / MAX • A, C and Z frequency weighting • iOS measurement mode: audio processing is switched off so readings are not altered • Calibration wizard plus built-in offset profiles for ~30 iPhone models • Honest clipping detection warns you when the mic reaches its limit PRO METRICS, COMPLETELY FREE • Noise dosimeter to NIOSH (85 dB, 3 dB) and OSHA (90 dB, 5 dB) standards • Live dose %, TWA and time-to-limit projection • Percentiles L10 / L50 / L90 / L95 • Time above threshold and a full dB histogram SEE THE SOUND • FFT spectrum with peak frequency readout • Scrolling spectrogram (waterfall) • 31 third-octave bands with peak hold DOCUMENT AND PROVE IT • Multi-page PDF report: chart, statistics, percentiles, dose and a threshold-exceedance table with start, end, duration and max • CSV and PNG export • Overnight and long-session recording with adaptive sampling, auto-stop timer and a quiet night preset • Session history with search, date and dB filters, tags, notes and markers • Trends dashboard: daily Leq, streaks, loudest day and hour PRIVACY BY DESIGN Audio is analysed live and never recorded or stored. No accounts, no analytics, no trackers, no cloud. Everything stays on your iPhone. You can erase all data at any time from Settings. ACCURACY NOTE NoiseLedger uses the built-in iPhone microphone, so readings are approximate and vary by device. It is a helpful indicator, not a certified instrument. For legal, workplace-compliance or safety-critical measurements, use a calibrated Class 1 or Class 2 sound level meter.

Turn your iPhone into a calibrated sound level meter, spectrum analyzer, and noise dosimeter. Built for fieldwork, inspections, and everyday measurements. Whether you are tuning a room, surveying noise on a job site, or checking workplace exposure, Frequency Analyzer gives you the data you need. REAL-TIME SOUND LEVEL METER - Live SPL readout with A, C, and Z weighting plus linear response - Fast (125 ms), Slow (1 s), and custom time averaging - Min, max, average, peak, and LAeq displayed continuously - Configurable reference calibration so your readings match a known source SPECTRUM AND SPECTROGRAM - Real-time FFT spectrum from 20 Hz to 20 kHz, linear or logarithmic axis - Scrolling spectrogram with selectable colormap and peak-hold markers - Octave-band view at 1/1, 1/3, 1/6, or 1/12 resolution - Classic oscilloscope waveform with adjustable time window - Amplitude-over-time history for slow trends across hours NOISE DOSIMETER Track noise exposure against NIOSH and OSHA criteria or a custom standard you define. The app accumulates dose throughout your shift, projects your 8-hour exposure, and reports the time-weighted average. Add event notes and export a PDF report with stats and graphs. REPORTS AND EXPORT - Reference tone generator from 20 Hz to 20 kHz for signal checks - CSV time-series exports for spreadsheets and analysis tools - Spectrogram PNG snapshots at configurable resolution - PDF reports with session statistics, charts, and event markers - Calibration and preferences stored locally on your device PRIVATE BY DESIGN Everything runs on your device. There is no account, no login, and microphone audio does not leave your phone. Sessions, notes, calibration data, and preferences stay in local storage. HOW TO USE 1. Grant microphone access and run the quick calibration walkthrough 2. Choose Analyzer, dB Meter, or Dosimeter from the tab bar 3. Use spectrum, spectrogram, waveform, octave, or amplitude history 4. Watch dose, peak, average, and frequency readings as you measure 5. Export CSV, PNG, or a PDF report when you need results Built for acousticians, safety officers, HVAC inspectors, musicians, and students who want serious acoustic measurement in their pocket. Free to download. Some features require a premium purchase. Privacy Policy: https://estifie.com/apps/frequencyanalyzer/privacy-policy Terms of Use: https://estifie.com/apps/frequencyanalyzer/terms-of-use