Carpets, pads are very good sound reducing materials. If you design a home theater system - one of the things you discover that what stops sound really well, are differing material densities. One such product is Quietrock, which is essentially drywall with a thin sheet of metal embedded in the plaster.
When you have a solid floor, then place a foam pad, and a carpet on top of it - you make a pretty effective sound barrier. Being a good neighbor means taking into consideration of not only what sounds are being masked by the existing flooring, but what shoulds you are muffling from going downstairs.
I have a friend who has a home theater in one of his upstairs rooms.
This thing is amazing:
65” screen
Booming stereo
theater seating complete with cup holders
The best part?
The room is on hydrolic jacks that moved the floor, bumped it and tilt all timed to the movie.
Even the seats have the ability bump, vibrated, etc timed perfectly to the movie.
Don’t know how much it cost but must have been $500k and he still pays a service fee to the company who installed it so they will take movies and program the room to be tuned to the movie.
Really nifty feature: You can’t hear it in the hall, the next room or even standing right under it in the kitchen.
They put down some kind of barrier that just plain stops the noise.
They played the last scene from Avatar. It was blasting real good when I left the room and then “poof”. Like a cloud as the door closed and I couldn’t hear it at all.