AudioUtil Spectrum Analyzer captures audio signals and analyzes them right on your phone in real-time. Screenshots of the display can easily be taken through the utility's context menu. Freeze the display by touching the screen and drag to show a value readout. Adjust multiple parameters for each utility like frame size zero padding window type range and themes to name a few. This app can be used with a 3.5mm 4-pole (TRRS) external microphone (non-USB) if supported by phone.

Utility Descriptions:

Oscilloscope:
• View sound waves in the time domain.
• Adjustable frame size.
• Amplitude measurement by dragging on the screen.
• Set trigger level to freeze display if audio exceeds amplitude threshold.


Decibel Meter:
• Max-peak or RMS amplitude readings in dBFS.
• View as a solid bar or multi-step graph.
• Peak tracking with variable time falloff.

FFT Graph:
• Linear and logged frequency axis.
• Six window types.
• Peak tracking with frequency and amplitude readout.
• Rendering filter for high-accuracy readings on stable signals.

Spectrogram:
• Definable frequency limits to zoom in on desired frequencies.
• Adjustable zoom/scroll speed.
• Four themes/color maps.

Frequency Spectrum:
• View a FFT analysis as a color spectrum.
• Linear and logged frequency axis.
• Four themes/color maps.

A note on required permissions: This app requests minimal permissions to record audio and to write to storage. These are required in order to successfully capture sound and save screenshots to the device.