Noise Logger

Noise Logger Professional ambient noise monitoring. Noise Logger runs continuously in the background, captures every sound event that crosses your threshold, and organises everything into detailed session reports you can share, export, and archive. **Designed for the field.** Whether you're conducting an environmental noise survey, documenting a construction complaint, assessing occupational exposure, or monitoring a mechanical system, Noise Logger gives you the tools professionals rely on — in an app that stays running all night if needed. **MONITOR** Real-time SPL display with NIOSH colour-coded exposure zones. A-weighted, C-weighted, or Z-weighted measurement with Fast or Slow time constants per IEC 61672. Session average (Lavg) and true peak (Lpeak) updated continuously. Mini spectrum analyser with live trigger markers. **RECORD** Threshold-triggered clip recording with configurable hangover to prevent fragmented events. Every clip captures peak level, average level, duration, GPS coordinates, reverse-geocoded location, trigger reason, and an optional snapshot photo. **ANALYSE** Full 0–20 kHz spectrum analyser with bars, lines, and scrolling waterfall display. Dedicated LoFar low-frequency analyser (5–1000 Hz) with FFT sizes up to 16,384 points. Eight FFT window functions including Blackman-Harris, Flat Top, and Kaiser. Frequency band and single-frequency triggers for tonal source monitoring. **EXPORT** PDF reports with session metadata, location, Google Maps links, clip table, and trigger reasons. ZIP archive with PDF plus all audio recordings and photos. Share via Mail, AirDrop, or any iOS share destination. **CALIBRATE** Import Dayton Audio microphone calibration files for per-frequency correction. Manual SPL reference and calibration offset. External USB and Bluetooth microphone support. --- **KEY FEATURES** · Continuous background monitoring — survives screen lock · Level, frequency band, and single-frequency triggering · GPS tagging with Google Maps links in reports · A / C / Z frequency weighting · Fast / Slow time weighting · Eight FFT window functions · Full spectrum and LoFar analysers · Bars, lines, and waterfall display modes · PDF and ZIP session export · Trigger reason logged on every clip · Snapshot photo on threshold crossing · External microphone support · Microphone calibration file import · No subscription. No ads. No data collection. --- **A NOTE ON ACCURACY** Noise Logger is a monitoring and logging tool, not a Type 1 or Type 2 certified sound level meter. iPhone microphones are optimised for voice, not flat acoustic measurement. Readings should be treated as indicative. For legally defensible measurements, use a certified instrument. The calibration offset allows you to trim readings against a reference meter for improved field accuracy. --- **PRIVACY** Noise Logger is entirely local. No internet connection. No analytics. No advertising. All recordings, photos, and session data stay on your device. noiselogger.com **Requires:** iOS 17 or later. Microphone permission required. Location and camera optional.