Decibel Meter Sonolab: dB SPL

SonoLab turns your iPhone into a powerful decibel meter and noise dosimeter, helping you understand how loud your environment really is. See sound levels live, track noise exposure throughout your day, and explore frequencies in real time — all using your iPhone’s built-in microphone.

Whether you’re checking noise on a plant floor, tuning a studio, working in a busy classroom or hospital, making music, or simply keeping track of a noisy environment, SonoLab gives you the tools to measure, understand, and document sound.

THE DECIBEL METER

Choose from nine measurement views, from detailed statistics to beautifully visual ways of experiencing sound:

• Bench — See a complete set of measurements including LAeq, LAFmin, L90, L10, LAFmax, and LCpeak
• Survey — Walk around your space and add markers directly to the measurement trace
• Limits — Quickly compare LAeq, LCpeak, and dose with your selected limits
• Steady — Know when a measurement has settled and you’re ready to stop
• Orbit, Trails, Nova, Ripples, and Eclipse — Experience the same sound measurement through dynamic visualizations

Choose A-, C-, or Z-weighting, with Fast (125 ms) or Slow (1 s) response. You can also calibrate SonoLab using a 94 dB reference or another trusted meter, with your calibration offset applied throughout the app.

THE NOISE DOSIMETER

Track your noise exposure throughout an entire work shift. The dosimeter works like a shift clock, showing how your exposure builds over time.

• See Dose %, 8-hour TWA, and the estimated safe time remaining at your current sound level
• Choose OSHA, NIOSH, or NOM-011 criteria and see all calculations update automatically
• Mark breaks so quiet periods aren’t counted as part of your exposure
• Keep measuring in the background while you work

FREQUENCY ANALYSIS

Take a closer look at what makes up the sound around you with six real-time analyzer views powered by FFT analysis:

• Octave-band bars and a 60-second waterfall spectrogram
• Peak hold and a visual representation of the last two minutes of sound
• RTA Pro — detailed 31-band third-octave analysis with an NC room rating and the band responsible for the rating
• Keys — see your sound mapped across a piano keyboard and identify the loudest note

HISTORY AND REPORTS

Your measurements are automatically organized into sessions, including sound levels, statistics, and noise exposure.

Rename sessions, review measurement traces, save spectrum snapshots, and export professional PDF reports with your measurement settings included.

Your history is backed up with iCloud, so your measurements can stay with you when you move to a new iPhone.

ALERTS

Want to know when noise gets too loud?

Set your own threshold and SonoLab can vibrate, flash the screen, or send a notification when the sound level crosses it — even while measuring in the background.

A NOTE ON ACCURACY

SonoLab is designed for surveys, awareness, monitoring, and documentation. An iPhone microphone provides an estimate rather than a certified measurement and may vary by a few dB or clip at very high levels, typically around 100 dB.

For the most reliable results, calibrate SonoLab against a trusted reference. When measurements need to meet formal compliance requirements, use a certified Class 2 sound level meter.

SonoLab is a powerful tool for understanding and documenting sound, but it is not a replacement for certified professional equipment.

PRIVACY

Audio is analyzed in real time. SonoLab never records or stores your audio.