Materials used in do-it-yourself soundproofing include panels, mass-loaded vinyl, damping compounds, fiberglass insulation and acoustic sealant. There are also soundproofed doors and windows prebuilt to save money and time. Well-regarded materials such as egg crates, foam panels and carpet squares only address sound absorption, one of the four principles of soundproofing, which is useful for improving the acoustics of a room but not for keeping out sound.
Mass, damping, decoupling and absorption are the four principles of soundproofing. Panels such as drywall, mass-loaded vinyl and sound-deadening fiberboard block sound by adding mass to the walls. These panels are effective for airborne sound such as voices.
Impact noises such as footsteps are transmitted through the building structure. Decoupling attenuates impact noise by adding gaps to parts of the structure to prevent sound vibration from traveling forward. Decoupling is the least-used technique because it involves tearing out the construction and requires careful planning.
Sound absorption is the least effective of the four principles of soundproofing, but it helps to prevent sound from bouncing off the surfaces of the room. Materials such as insulation, foam and acoustic tile are effective at soundproofing the ceiling.
Damping compounds convert sound energy into heat, which stops sound abruptly. These compounds must be applied between two stiff panels, which are later screwed together. This is particularly effective for low-frequency noise.
Acoustic sealant increases the effectiveness of soundproofing by preventing sound leakage. The homeowner seals seams between soundproofed surfaces and applies the sealant around doors, windows and electrical boxes.