In an increasingly noisy world, the concept of acoustic design has taken on a significance that few architects would have predicted a generation (0) AGO. Modern buildings are being designed not 1 to be visually appealing but also to provide refuge from the constant assault of urban noise. Were it 2 for the groundbreaking research carried out by acoustic engineers in the 1970s, many of the techniques now used in soundproofing would not exist. Remarkable 3 it may seem, the shape of a room can influence noise levels just as much as the materials from 4 it is constructed. In hospitals, excessive noise has long been identified as a factor that impedes patient recovery, and yet it is only recently that the problem has begun to 5 taken seriously by those responsible for building design. So significant are the benefits of good acoustic planning 6 some researchers now liken sustained quietness to a form of therapy. It is this realisation, rather 7 any single innovation, that is driving what many in the field refer 8 as a quiet revolution in architectural thinking.