These decrease reverberation and so make rooms quieter. However so called acoustically hard materials such as glass and concrete, which are commonly used in interior design, scarcely absorb sound at all. Heavy curtains made of material such as velvet are often used to absorb sound. On the other hand, lightweight and transparent curtains are acoustically almost useless. At least they were until now.
Together with a silk weaving company and a textile designer Empa researchers have developed a new curtain fabric that is lightweight but still absorbs sound.
“Acousticians are pretty astonished when they see the readings we are achieving with the new curtains in the reverberation room. The weighted sound absorption coefficient is between 0.5 and 0.6”, commented Kurt Eggenschwiler, Head of Empa's «Acoustics/Noise Control» Division. The new textiles quench five times more sound than conventional translucent curtains.
The first acoustically optimised lightweight textile came into being on a computer. The Empa acousticians wanted to use the characteristics of this virtual textile in order to prepare a kind of recipe for material experts, which would enable them to specifically manufacture a fabric that could absorb sound. In addition, they first developed a mathematical model to illustrate both the microscopic structure of the fabric as well as its macroscopic composition. On the basis of numerous acoustic measurements made on various samples, they were able to gradually optimise the acoustic properties of the fabric.
COMPAMED.de; Source: Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt