I realized I'm experiencing a situation that doesn't make any sense to me at all.
Back at home, my room is on the top floor of our apartment building. There is a daily music playing fountain nearby and I can hear the songs as if the fountain is my room. I have always thought that there must be speakers somewhere nearby because it is impossible for the music to reach my room. I cannot hear the music when I leave the apartment (the apartment exit faces the same way as my window) in fact, I cannot hear it until I walk 4-5 mins towards the fountain. My room is on the 6th floor.
This year I started graduate school and as a new student, I was trying every floor of the library to see which one I'll like the best. After a while, I decided that I liked the top floor (10th) the best and kept studying there. The only thing I couldn't figure about the top floor has been the music I kept hearing which I didn't hear on any other floor. I was thinking of a secret 11th floor filled with musicians until today I found out the music is coming from the park nearby. The thing is that you cannot hear the music at all on the lower floors which are actually physically closer to the park! So instantly I remembered the similar experience I lived back in my apartment and realized there are probably no speakers hanging around to stream the music that is playing at the fountain.
Could anyone explain why that happens? The only explanation I could come up with was that the top floor is only isolated with the roof unlike other floors (which have other floors as isolation layers) so maybe the roof is not a good isolator? Because in my apartment my room is always warmer in the summer and colder in the winter with respect to the other floors. But I don't know if heat works similarly to sound.