To soundproof a room, incorporate more materials that absorb sound and seal doors well. Everyday items like carpet and blankets help, but specialized products are more effective.

Create a gallery wall of flat, polyester fiber sound-absorbing panels (the BXI Sound Absorber panels are $19.95 on Amazon!) This material has been engineered to absorb a wider range of frequencies ...

2) Absorb sound within the room (or within wall cavities, as has been noted already). This is where heavy hangings, purpose-made acoustical baffles, heavy rugs, and all of that sort of thing comes in.

A government-run film theatre complex in Kerala has set up a “crying room” for parents to take their children who get uncomfortable inside a theatre. The sound-proof room comes with a few ...