At the heart of Strand Duo are the very basics of noise/vibration control technologies. As trains and automobiles zip past at average speeds of upto 120 kmph they emit noise waves which are broadband in nature and encompass low, mid, high frequencies. These noise waves impact noise barriers that are usually placed on both sides of the railway or roadway. The low frequency (LF) sound waves additionally induce structureborne vibrations.

Usually noise barriers, either reflect more sound energy back to the track or road, to the greater discomfort of passenger, or allow sound energy to passthrough to the greater discomfort of occupants of adjacent buildings. There are also issues of outdoor durability, aesthetics, vandalism, economy etc. So, the question has always been how noise barriers can be designed optimally into a winning ratio of price:performance and other parameters?

Anutone Noizkon, after years of research and field trials, has perfected a product that optimises the control of such noise waves and delivers true value. Strand Duo consists of three interconnected components. A low-density outer layer that faces the track or road and absorbs the first wave of noise, especially, MF & HF. An automatic air-cushion that enables an impedance mismatch and further absorbs the LF. A high-density inner layer that faces buildings and acts as both an LF absorber and isolator.

Eureka moment is that all three layers are dynamically balanced and resiliently mounted in such a way that induced vibrations (structureborne) due to LF are dissipated. Strand Duo is placed in a metal sleeve that is attached to the posts. This results in the greatest efficiency of the system with very litte throwback of noise to the track or road and very little pass-through of noise to the buildings. A win-win for the entire ecosystem.