Audio Lab: SPL & Spectrum

Audio Lab turns your iOS devices into a modern set of audio measurement tools: a real-time spectrum analyzer, an FFT analyzer, and a sound level meter, with a built-in signal generator.

RTA
Live octave and third-octave band levels of the incoming sound, with peak hold and NC / NR rating.

FFT
High-resolution spectrum with selectable window and size, averaging, octave smoothing, and a cursor that reads frequency and level. Peaks are marked automatically. Export the current spectrum as an image or a CSV file.

SPL
A sound level meter with A, C and Z frequency weighting, Fast and Slow time weighting, Leq, Max, Min and peak readings, and a 60 second history. Switch between a bar view and a dial view.

Signal generator
Sine, square, triangle, sawtooth, white noise, pink noise and sweep, available inside the RTA and FFT screens.

Calibration
Enter a calibration offset for each input device by hand, or calibrate with an acoustic calibrator. Without calibration the built-in microphone shows an estimated level, and the app labels it as an estimate.

Private by design
Audio is analyzed on the device in real time. It is never recorded, stored or sent anywhere.