A method and a loudspeaker construction (10), in which loudspeaker construction spherical acoustic wave fronts emitted by the diaphragms (12) of speaker elements (11) are transformed into a uniform, planar acoustic wave front. The loudspeaker construction (10) comprises a plane wave channel (20), in the surface (26) of which plane wave channel directed towards the diaphragm (12) there are adjacent sound inlet apertures (24) for transmitting acoustic waves into ducts (23) and, on the opposite side (22) of the plane wave channel, there are outlet apertures (25) for transmitting acoustic waves from the ducts into a horn portion (30). The ducts (23) taper so that the width (B) of the outlet apertures located in a row on the side of the horn portion is less than half the diameter (D) of the diaphragm.