Smart curtains swallow noise

New lightweight, translucent curtain fabrics absorb five times more sound than conventional products

For the acoustic tests, the new sound-absorbing curtains are hung in a typical boardroom at Empa in St.Gallen. © Empa
Read out

Swiss researchers have developed light, translucent curtain fabrics that absorb five times more sound than conventional products. Recently, the new noise-absorbing curtains are now on the market and could in future be used in offices, meeting rooms, restaurants or hotel lobbies.

Noise annoying. It disturbs the communication, reduces the work performance and makes one tired - in extreme cases even sick. Sound-absorbing surfaces are therefore necessary in rooms where people work, talk or relax. They shorten the reverberation and make the rooms calmer.

New tissue developed

However, so-called reverberant materials such as glass and concrete, which are often used in interior design, hardly absorb sound. Often used as a sound absorber therefore heavy curtains, such as velvet. Lightweight and transparent curtains, on the other hand, are virtually ineffective acoustically. At least that's what they've been up to now.

Together with an industrial partner and a textile designer, researchers at Empa (Swiss Federal Laboratories for Materials Testing and Research) have now developed a new fabric for lightweight yet sound-absorbing curtains.

Measurements of sound absorption in the Hall of Empa: At a distance of 15 centimeters between the curtain and the wall, the new curtain - depending on the frequency - absorbs up to five times more sound than conventional light curtains. © Empa

New curtain as a sound absorber

"Acousticians are astonished when they see the corresponding characteristics we have achieved with the new curtains when measuring in the reverberation room. The weighted sound absorption coefficient is between 0.5 and 0.6 ", says Kurt Eggenschwiler, head of the Empa department Acoustics / Noise Reduction. display

Say: The new textiles " take" five times more sound than conventional translucent curtains. Eggenschwiler: The new curtain is a real sound absorber, which noticeably improves the room acoustics, erst and even of high design quality.

A real market gap

Another advantage: as the new curtains are translucent, according to the scientists, they can be used in a variety of ways, for example in offices, conference rooms, restaurants, hotel lobbies, seminar rooms and all-purpose auditoriums. Often, they make the crucial contribution to fulfilling the acoustic requirements and guidelines that apply to these rooms. The fact that the new textiles close a market gap is already apparent shortly after the market launch; the interest is enorm, Eggenschwiler.

Recipe sought for sound-absorbing tissue

The idea of ​​a curtain absorbing at the same time light, translucent curtain comes from the textile designer Annette Douglas, who has been dealing for some time with the interaction between sound and textiles. Together with the Empa researchers and the silk weaver Weisbrod Z rrer, in 2010 she submitted a project to the Commission for Technology and Innovation (CTI). No easy task, because thin and translucent fabrics are usually miserable sound absorbers.

The first acoustically optimized lightweight textile was therefore developed on the computer. Thanks to its properties, the Empa acousticians wanted to give the textile professionals a kind of "recipe" with which a sound-absorbing tissue should be specifically produced. For this they first developed a mathematical model that depicts both the microscopic structure of the tissues and their macroscopic structure.

Fabric acoustically optimized step by step

In combination with innumerable acoustic measurements on various samples woven by Weisbrod-Z rrer, they were able to acoustically optimize the fabric step by step. Douglas was then able to translate the new findings webtechnisch. She chose the yarns that gave the fabrics the necessary properties in terms of flammability and translucency, and determined the fabric construction, meaning how the threads should be woven into each other.

Finally, silk weaving could adapt the demanding production processes so that the industrially produced curtains actually had the desired acoustic properties.

(Empa - Swiss Material Testing and Research Institute, 04.05.2011 - DLO)