Soundproofing??

The only way to reduce sound is to add mass. Hang blankets from the ceiling all the way around your room in layers an inch from the wall. That should help. You can also get muffling rings or practice pads for your drums. Another option is to go electric. I got a roland v-drum set entry level for 6 bills and you can play it with headphones.

You could also go to mufflers and triggers. Where the drums are quiet but the triggers send a signal of each note to a brain that plays them back like an electric set, so you could control the volume.