Patent ID: 6778677
Filing Date: 2004-08-17
Classification: H04R

Abstract:
A loudspeaker comprising:A) a loudspeaker basket, B) a loudspeaker cone suspended from said loudspeaker basket for displacement along a loudspeaker axis, B) first and second magnet structures that define first and second annular magnetic air gaps, respectively C) a motor frame supporting said first and second magnet structures on the loudspeaker frame with the first and second annular magnetic air gaps in a counterfacing relationship and centered on the loudspeaker axis, D) first and second voice coils for being energized by alternating current signals, E) an armature extending along the loudspeaker axis and supporting said first and second voice coils in the first and second annular magnetic air gaps, respectively, F) a centering support transverse to the loudspeaker axis and attached to said motor frame and said armature for centering said armature radially on the loudspeaker axis during axial displacement of said armature along the axis, and G) a rigid link connecting said armature and said loudspeaker cone whereby alternating current applied to said first and second voice coils causes said loudspeaker cone to undergo a corresponding displacement and said armature is constrained to axial motion without radial displacement with respect to the loudspeaker axis.