A voice coil bobbin construction for a planar diaphragm loudspeaker including plural bobbin frames joined together to form the composite voice coil bobbin. In one embodiment, the bobbin frames each have a coupling member at each end thereof which are bonded together in a planar contact. Reinforcing ribs may be provided extending parallel to the planar diaphragm. In another embodiment, a mounting flange intimately bonded to the planar diaphragm and a voice coil flange upon which the voice coil is mounted are provided. A damper fastening portion can also be formed by leaving a portion free of through-holes in the bobbin frames. The feeder wires to the voice coil can be run through the through-holes in the bobbin frames.