Strange happenings.

Soo about a week ago I was woken up to the sound of our smoke alarm going off for no reason (about 1:00am btw) and our dog barking at the smoke alarm in the corner, looking absolutely terrified. Not super strange on its own but 2 days later our home theatre speaker system started making noises whenever me or out dog went near it. The smoke alarm kept going off at about one o clock ever morning, so 2 days ago we got a new one, the same thing happened again last night. I do not know what to do but some advice/theories would be helpful. Thankyall.