Patent attributes
Radial input waveguide is provided having three consecutive sound wave propagation passageways, virtually divided by two folding regions along its extension from radial input up to substantially rectangular output, each one forming a different type of waves and all three channels shaped between an internal body and a shell housing enclosing it at a distance. The radially expanding initial air channel forms a cylindrical wave front between two input walls. A relatively wide region with parallel walls is available for wave folding at adaptably changeable diameters in this region with a small distance between the folded walls. All individual partial wave fronts on the periphery of the first folding region are traveling along substantially equal, accumulated from the last two air channels, path lengths, to the waveguide output, forming there a common isophase and planar wave front. The middle passageway contains all the physical dimensions necessary to control the waveguide performance, the most important being the height H and the width D, whose ratio controls the wave front output curvature.