There are many reasons to soundproof a room or building, whether you're building your own recording studio or just want to keep noise out and enjoy the peace and quiet. Some companies offer tiles and other materials that can be attached to the walls and ceilings, but these can be expensive and inconvenient. There are several relatively inexpensive ways to soundproof a room.
First, it's important to understand what kinds of materials absorb and dampen sound. The way the building and room are constructed also plays a role in how noisy the room is. If there is plenty of insulation and space between the inner and outer walls, a room is likely to be quieter. If you cannot make structural changes to the building, find ways to attach things to the walls, floors and ceilings to help them dampen rather than transfer sound.
Irregular surfaces help keep sound from transferring, while flat, smooth walls and ceilings do not. Sometimes, just hanging heavy drapes on the walls can have a significant impact on the amount of sound transferred into and out of a space. Heavy carpeting also helps to dampen sound. You can install wall-to-wall carpeting, or you can use remnants over the whole area of the floor. Carpeting can be tacked onto the walls as well, and heavier carpeting can help eliminate a lot of sound. Cardboard can also be used. Egg cartons and similar materials are cheap and can be applied in one layer to the wall. These should then be covered with a heavier material, such as carpeting or drapes. This will provide an extra layer and some more insulation, which will help reduce noise transference. You can purchase carpet remnants to save money on materials, and you can buy bolts of heavy fabric to hang in place of drapes.
You can also apply an acoustic spray texture to the walls and ceiling, which helps to make the surface rougher so it is less likely to transfer as much sound. Suspended ceilings are another option, because they usually have a rough texture that doesn't transfer sound, and they provide an empty space between the real ceiling and the suspended ceiling, allowing for further sound insulation.
Doors and Windows
Noise is often transferred through doors and windows. These can be soundproofed as well. Weatherstrips and other draft guard materials can help eliminate sound in these areas. Double-paned glass in the windows will also provide a buffer zone that can reduce sound. For further soundproofing of windows, hang heavy drapes, regardless of what other methods you may be using in the room. The heavier and more textured the drapes, the more sound reduction they will provide. Mixing two or more methods of soundproofing will more dramatically affect the sound levels in your room.