Patent ID: 7684582
Filing Date: 2010-03-23
Classification: H04R

Abstract:
1. An acoustic transducer, comprising: a pole piece comprising a first end; a voice coil comprising wire windings configured to receive electrical current, the voice coil being configured to move along the first end of the pole piece; a magnetic structure comprising parts defining an air gap, wherein the voice coil on the first end of the pole piece is disposed in the air gap so that the magnetic structure creates a magnetic field in which the voice coil is configured to move along the first end of the pole piece; a diaphragm comprising an inner periphery defining a central opening and an outer periphery, the inner periphery of the diaphragm being attached to the voice coil to move with the voice coil; wherein said diaphragm is configured to move as a piston; a waveguide extension structure attached to the first end of the pole piece; and an inner flexible roll seal coupled to the diaphragm and to the waveguide extension structure, wherein the inner flexible roll seal seals a gap between the voice coil and the first end of the pole piece.