Had the new headseats on fly 20 DFW to LHR. Didn't work at all. FA swapped them our 4 times nothing, no sound. But when I puled my earbuds into the jack I got sound. Had to give up. Mrs. Deac83 had the same problem. We both used our earbuds for the flight. On/off switch did nothing. There is no light on these to indicate that they are in fact on, and assuming it has a batter that it's still good.
I also found them uncomfortable, just used them to block noise while I as sleeing, but my ears were sore and I had to fiddle with the head adjustment.