Wondering if I can call on your collective knowledge for something!
I have a Dynaudio BM14s Subwoofer that has recently started to switch itself off, even with a relatively low signal. It looks like it's going into mute mode (the green led goes red), and if that happens, I only get a very low signal, the same as if it was not switched on at all.
If I leave it off for a while and try it again it will power up as normal, and the audio is fine but then it will just cut itself off again. Sometimes it will even switch off with no signal! When I do manage to get audio through it, it sounds fine so at least I know I haven't completely killed it!