Curtains that quench noise

Noise is annoying. It interrupts communication, reduces productivity and tires people out – in  some cases, noise can cause long term psychiatric disorder. It is however unavoidable in Hong Kong, a city of hustle and bustle.

Researchers at Empa, in cooperation with textile designer Annette Douglas and silk weavers Weisbrod-Zürrer AG, have developed lightweight, translucent curtain materials, which are excellent at absorbing sound. 

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, specifically woven by Weisbrod-Zürrer, they were able to gradually optimise the acoustic properties of the fabric. Annette Douglas then succeeded in translating the new findings into weaving techniques. She chose yarns that gave the materials the necessary characteristics in terms of flammability and translucence and determined the weave structure, i.e. how the threads should be woven in and out of each other. Weisbrod-Zürrer then adjusted the sophisticated manufacturing process so that the industrially-made curtains actually displayed the required acoustic characteristics.

The above graph is the sound absorption measurements in Empa’s reverberation room. With a gap of 15 cm between curtain and wall, the new developed curtain – depending on the frequency – absorbs up to five times more sound than typical lightweight curtains.

Because the new curtains are translucent, they can be used in a variety of places such as offices, living rooms, restaurants, hotel lobbies, seminar rooms and even multi-purpose auditoriums.  They are often the deciding factor in satisfying the acoustic requirements and regulations that apply to these rooms. These curtains may be a solution to the noise in Hong Kong - what do you think? 


Further reading: 
Product sheets for the curtains