Abstract: One embodiment provides a slim acoustic transducer with a diaphragm including a hole that is substantially centered on a vertical axis of the diaphragm. The hole has a first horizontal width. A voice coil has a ring shape that is disposed at least partially within the hole and substantially centered on the vertical axis. The ring shape has an outer and inner horizontal width. The outer horizontal width is smaller than or equal to the first horizontal width of the hole. A column structure is disposed at least partially within the ring shape and substantially centered on the vertical axis. The column structure has a second horizontal width that is smaller than or equal to the inner horizontal width of the ring shape. The column structure includes an upper magnet, a middle plate disposed below the upper magnet and a lower magnet disposed below the middle plate.

Abstract: One embodiment provides a slim acoustic transducer with a diaphragm including a hole that is substantially centered on a vertical axis of the diaphragm. The hole has a first horizontal width. A voice coil has a ring shape that is disposed at least partially within the hole and substantially centered on the vertical axis. The ring shape has an outer and inner horizontal width. The outer horizontal width is smaller than or equal to the first horizontal width of the hole. A column structure is disposed at least partially within the ring shape and substantially centered on the vertical axis. The column structure has a second horizontal width that is smaller than or equal to the inner horizontal width of the ring shape. The column structure includes an upper magnet, a middle plate disposed below the upper magnet and a lower magnet disposed below the middle plate.