Soundproofing your home theater is important for a few reasons. For one, you'll improve the sound quality of your theater with proper acoustics. Two, you'll keep sound from the rest of the house out -- no interruptions from the washing machine, dishwasher or the blender [source: SoundproofFoam]. Those kinds of intrusive noises always seem to pop up during the quietest, most dramatic scenes, don't they? The third reason to soundproof your room -- and probably the most important -- is to keep the movie's soundtrack in.
If you live in a giant house out in the middle of nowhere, this probably isn't as important. But without proper soundproofing, loud movie scenes could disturb other people in the house, or worse, your neighbors, who might call and complain about your infernal racket. So covering your home theater walls with acoustic panels can improve sound quality, while padding and insulation can cut down on noise transmitted through walls and floors [source: SoundproofFoam]. Properly insulating the room should effectively isolate the home theater from the outside world, leaving us one major intruder to contend with: light.