Sound-producing device with acoustic waveguide

A sound-producing device including at least one acoustical generator and an acoustical waveguide provided with an entry to which said acoustical generator is connected and an exit of chosen shape from which an acoustical wave propagates to the outside, wherein said waveguide includes two duct sections, namely a first section aligned with said exit and a second section aligned with said entry, said two sections are connected partly by a curved reflecting surface having substantially the shape of part of a conic section surface, and said entry is in a vicinity of a focus of said conic section surface.