The piano in the basement

At my old house I use experience lots of paranormal things. One of the last crazy memories I have of stuff was the time I was in the living room with my brothers. It was mid day no one was home but us we were sitting talking and playing videos games when all the sudden we heard the piano in the basement go off. Remember we were fully home alone and we three were all in the living room. It was a very high note on the piano and one of the creepiest ones it then did it once more . Then we started to really freak out because how the hell was the piano playing with no one down there . We immediately started trying to figure out what it could’ve been but the thing was it couldn’t have been a glitch because the piano still works to this day. Number two no person could have done it so what did. Also to mention this was like a tiny learning piano not some huge fancy one that could be rigged or anything. It was so Erie. We had lots of crazy paranormal experiences there.