took a nap for an hour, thinking maybe I’ll sleep till 4 (which would be fine).but I woke up after an hour with a pounding headache certain I heard a tinny voice, coming from a speaker or something, but I had nothing on. It didn’t repeat. I thought maybe it was one of my smoke alarms but they’re green all good and again it didn’t repeat. I haven’t heard any other movement in the building either but I suppose it could have come from upstairs/downstairs (I do hear the vibration whenever my upstairs neighbour sets his alarm, he must charge it on the floor). Anyhoo I was half asleep chances are it was in my head.