Lumisound

Lumisound turns audio into a real-time spectrogram. The same kind of visual frequency analysis used in professional audio software, now in your pocket.
Use it for anything. A car engine, musical instrument, room sound, and watch the frequencies unfold in real time, colour-mapped from silence to full scale.

Features:

Real-time spectrogram with colour mapping
Full 20Hz–20kHz frequency range
Peak frequency detection with dBFS readout
Export full session spectrograms as high-resolution images
Audio file analysis
Frequency checker
Clean, minimal interface
File playback
Frequency generator with multiple wave shapes
Decibel meter with exportable trace graph
Input mic selection

And all of this? Free, forever. No ads, subscriptions, or in-app purchases.