A loudspeaker has a diaphragm (20) with a voice coil (32a, 32b) disposed about its perimeter and extending in a gap (25) into which the flux of an annular rare earth magnet (10) is focused. The voice coil may have two or more windings that are connected in parallel, and may, e.g., be layered on top of one another, so that the impedance of the coil, as well as its depth in the front/back direction of motion, are low. The voice coil is preferably implemented using a polyamide form or bobbin (30), which has patterned lead-in conductors (31) embedded therein to bring power to wire windings on the perimeter of the coil. A diaphragm may be domed to provide further clearance, and is mass loaded by a material (22) such as butyl rubber to lower its resonance and improve performance. A flat diaphragm may also be used, and pole pieces (11) may be formed of materials such as chrome vanadium instead of cheaper iron materials to further reduce the overall thickness and weight without sacrificing the gains in efficiency and engine strength of basic construction.