Practicing music in a room can work when no one else is home, being that that’s not usually the case you’ll need some simple solutions. First off is the door it’s the weakest link, It’s only one layer its got gaps on the bottom and on the sides. Start by applying proper door seals to your door perimeter. Then beef up the door itself. You can do it on your own by adding a 2nd layer of MDF over the door and applying a layer of damping compound like Green Glue in between.