A free app for Android, by RedVox.
Infrasound Recorder is an app for capturing and recording sub-aural low frequency sound from volcanic eruptions, sonic booms, meteors, earthquakes, tsunamis, surf, and anything big that blows up. It is designed for Android OS7 Nougat and above.
The way this works is that the app takes an audio recording from the microphone, filters it to remove any sound above 80 Hz, then sends it to the server. The server then processes the data, creates a plot of the sound pressure and sends it back to the device.
The app can be used in the background, which allows you to keep using your phone or tablet while it records. When the recording is done, you can access all the recorded data. The recorded data is saved in the device's memory, so you don't need to worry about storage space.
The RedVox Infrasound Recorder is designed to be used as an emergency tool, so you don't need to worry about privacy. The recorded data is transmitted anonymously to the server, which is protected by a 256-bit encryption. The data sent to the server is processed by an algorithm that removes any information that can be used to identify you.
