Patent ID: 8208678

Claim:
An air-motion-transformer loudspeaker, comprising: two pole plates disposed to define an air gap therebetween; a substantially meander-shaped membrane disposed in said air gap, said membrane having a plurality of flank sides and a plurality of wave crests and wave troughs, extending in a longitudinal direction of said membrane; conductor tracks extending along said plurality of flank sides; mutually opposing said flank sides delimiting air pockets and respectively opposing individual said flank sides moving towards and away from one another in a transverse direction of said membrane during an operation of the loudspeaker; each said wave crest and each said wave trough being defined with an axial center line and each carrying one or more strip-shaped stiffening elements, said stiffening elements being disposed on said axial center lines and extending evenly in the longitudinal direction; said stiffening elements being formed and disposed to cause said flank sides to move towards and away from one another while remaining parallel to one another and to cause the axial center lines of said wave crests and said wave troughs to retain an axial orientation in the longitudinal direction of said membrane during the operation of the loudspeaker, and to prevent non-parallel oscillations of said flank sides relative to one another and bending of said flank sides during the operation of the loudspeaker.