Simple recording app with real-time spectrum display

I’m working on a product that emits high-frequency audio at live events.

We need the organisers to test the venue sound system beforehand.

These people seem utterly incapable of following instructions. Invariably they take matters into their own hands, making recordings with unsuitable apps and sending them to us in an unsuitable format. As often as not the frequency band of interest has been erased thanks to some compression somewhere along the line.

So, I would like to create a very simple test app. When it hears a 440Hz tone for 0.1s it starts recording. When it hears a 660Hz tone it stops recording and sends the raw data to our server.

It would also be nice if the app can display real-time frequency activity between 15-20kHz.

It’s rather fun project, I just don’t have time to code it up myself.

If it sounds interesting, please shoot me a line. pi | pipad | org