Acoustic barriers based on periodic arrays of scatterers

It is well known that certain periodic structures built by repetition of elements produce sound attenuation effects as a consequence of the destructive interference of the scattered waves by these elements. The sound attenuation results that we got from transmission experiments with these kind of structures, so-called sonic crystals (SCs), led us to think that SCs could be used as an acoustic barrier. Until now, most of the transmission experiments with these periodic arrays of scatterers have been performed under controlled conditions, so how they would behave outdoors is still not well known. In this letter we present outdoor-experimental results for two-dimensional SCs and from these it can be concluded that periodic arrays of scatterers are a suitable device to reduce noise in free-field conditions.