We soundproofed the room so we couldn't hear the road noises; unfortunately we couldn't hear the fire alarm either.
A soundproof room, door, or window is designed to prevent all sound from getting in or out. The studio isn't soundproof
If you soundproof a room, you line it with special materials to stop all sound from getting in or out. We've soundproofed our home studio. a soundproof wall, room etc is one that sound cannot pass through or into. to make something soundproof