Sound proofing refers to the reducing or minimizing of sound pressure with respect to the specified sound source and receptor. There are various way to apply sound proofing and thereby reducing sound. Sound proofing by using noise barriers is one such way, and will absorb or block sound waves with damping structures such as sound baffles. Another way to sound proof, is by simply increasing the distance between the source of the noise and the reciever. Sound proofing is effective in two different ways, noise absorption and noise reduction. Noise reduction blocks the path of the sound, while noise absorption works by transforming the sound wave. Sound proofing is very often used for residential purposes, and this generally refers to the windows. Double glazing is quite effective for soundproofing, as are the use of heavy curtains.