Windows – Mystery radio station playing through headphones. How to find all sources of sound?

There is a radio station that intermittently plays through my headphones when they are plugged in. It does not play through the stereo speakers of my laptop.

When I open the volume mixer, it does not show any sound being played, even though there is sound coming through my headphones.

The sound does not get louder or quieter when I change the volume.

I have closed all browsers, and the sound still comes through.

How can I find a list of all programs that are outputting sound?

Solution:

I’m going to go with Interference. Very hard to know exactly what causes it, but could be fixed by experiment with things like: Re-route wires, unplug unused things, clean plugs, different outlets, sit in a different position, move things around…