Device for diffusing air particularly in a motor vehicle air conditioning installation

The air distribution device has an air conduit system with a number of air channels (2) feeding conditioned air to different air outlets and a distributor organ, rotated within a housing for opening individual air channels via an opening (3) in the distributor organ. The latter is in the shape of a bell or a truncated cone and has at least one elastic region, e.g. a foil supported by a frame.