Loudspeaker with single layer rectangular wire voice coil wound on slit metal bobbin with a notch in the adjacent pole plate

In a loudspeaker assembly including a basket, diaphragm and means defining an air gap having a magnetic field therein, the improvement comprising,

• a single-layer voice coil formed by conducting wire of rectangular cross section wound upon a sheet metal bobbin having a longitudinal slit and an end portion of the conductor comprising the coil folded over from one end of the single layer to the other end,
• the means defining an air gap including a front pole plate formed with a central opening that comprises means for defining the air gap and a notch extending radially outward from the central opening of area slightly greater than the cross sectional area of the folded-over end portion with the folded-over end portion passing through said notch in noncontacting relationship with said front pole plate,
• and means for supporting said voice coil and bobbin in said air gap to substantially fill said air gap while being in noncontacting relationship with said means defining an air gap.