Industrial automation monitoring is a major commercial application. I was going to look at https://www.minidsp.com/products/usb-audio-interface/uma-16-... for doing it. Do you know what limits of detection you could get, and on what equipment?

Monitoring structural vibrations is also useful, and I think is an ongoing research area. I mention this because it's possible to sell it and research it at the same time.

What about synchronized cameras in different locations?