Moving-coil loudspeaker - has two membranes with coils moving in concentric airgaps

摘要

The loudspeaker has a first coil attached to a first membrane and a second coil attached to a second membrane. The second membrane is located inside the first membrane. The two coils (22,38) are concentric and lie in roughly the same plane and on the same side of the membranes (24,40). The smaller inner coil moves inside an inner air-gap. The larger outer coil moves inside an outer air-gap concentric with the inner air-gap. Both air-gaps are in the same magnetic system. Combining two loudspeakers into one in this way improves the uniformity of its sound radiation characteristics.