A loudspeaker comprises a horn waveguide having a waveguide surface, and a transducer located in, or adjacent to, a throat of the horn waveguide. The transducer has a substantially rigid convex dome-shaped acoustically radiating surface. A horn angle subtended between a longitudinal axis of the horn waveguide and the waveguide surface at the throat of the horn, is in the range 20 to 60 degrees. An intersection angle subtended between a plane tangential to the dome shape of the acoustically radiating surface and a plane tangential to the waveguide surface at a point where the dome shape or an extrapolation of the dome shape meets the waveguide surface or an extrapolation of the waveguide surface, is in the range 85 to 110 degrees.