Enhancing acoustic comfort with window coverings: Reducing sound transmission and reverberation times with a single product

Abstract

Window coverings have traditionally been used for design and light control only. However, they also present a great opportunity for a complete acoustic treatment. This is for a number of reasons: (1) They are installed over glazing which represents the typical weak point through which sound enters the space; (2) they have a large surface area for absorption; and (3) they are a natural fit in most modern spaces allowing architects, designers, and clients freedom in their design unconstrained by acoustics. By combining mass loaded vinyl to target sound transmission and absorptive surface linings to provide sound absorption, it is possible to significantly improve acoustic comfort with installation of acoustic curtains. This paper presents the results of extensive laboratory tests on such acoustic curtains, where the diffuse field sound reduction index and sound absorption coefficients were measured for four glazing conditions (open window, 4 mm glass, 6.38 mm glass, and 10.38 mm glass) with 15 different curtain configurations, totalling 76 tests. The results demonstrate significant sound level reductions with the addition of the curtains, with a weighted noise reduction index improvement as high as 13 dB, and a noise reduction coefficient of 0.65 for an additional 2 kg per square metre.