Acoustic foam is a sound absorbent material used to line rooms or spaces in which sound-reflective surfaces produce unwanted reverberation and echoes, or where the travel of sound either into or out of the space is undesirable. Soundproofing foam is commonly used in recording studios, edit rooms, broadcast studios and home studios, although it can also be used to sound-proof a room containing a surround sound system or laundry room equipment.
As with other soundproofing materials, acoustic foam absorbs the sound waves, and reduces the effects of reverberation or reflected sound waves, which result in noise pollution. It allows the sound energy to penetrate into the material and be dissipated by its cellular or fibrous nature prior to reaching the reflective surface it is mounted on. This sound proofing foam is typically made of urethane open-cell foam. Open cell foam is soft foam in which the cell walls, or surfaces of the bubbles, are broken and air fills all of the spaces in the material. This makes the foam soft or weak. Airplane companies use the sound proof foam to line the walls of a passenger cabin, eliminating the noise within the airplane. Other areas where acoustic foam might be found are gyms, cafeterias, music clubs, function halls and churches.
The insulation value of the foam is related to the insulation value of the calm air inside the foam. Sound foam products solve troublesome structural vibration and reduce noise by alleviating slap and flutter echoes, especially in areas used for acoustic recordings. Acoustic foam materials can also be used in panels, ceilings and flooring to create sealed environments of clean sound. The greater the surface area of the foam, the greater the sound absorption qualities it possesses. Therefore, sound foam is often constructed with pyramid or egg crate style surfaces. Occasionally, it is covered with a film surface treatment which provides an excellent solution for use in harsh, moist, high temperature and chemical environments. Sound proof foam is an inexpensive form of soundproofing and is treated with dyes and/or chemical flame retardants such as an epoxy; this keeps it safe from excessive heat. However, it is a highly flammable material and should be used with caution in any areas making use of flames. The foam is also available in different colors, patterns and ranges of thickness, commonly found in 1" - 4" measurements. Alternative soundproofing materials to acoustic foam include rubber, magnesium oxide, and fiberglass.