Patent ID: 7426281

Claim:
An electroacoustical transducer comprising: a chassis ( 3 ); a rigid surface ( 10 ) rigidly attached to said chassis ( 3 ); a moving membrane ( 7 ), attached flexibly to said chassis ( 3 ) and positioned to face said rigid surface ( 10 ), with an air mass between said rigid surface ( 10 ) and said moving membrane ( 7 ), where in a distance between the rigid surface and the moving membrane increases in size from a center to a periphery; and a driving device ( 4 , 5 , 9 , 9 b ) to displace said moving membrane ( 7 ) in the direction of said rigid surface activated by a modulating electric current; the displacement of said membrane ( 7 ) generating, by compression and expansion of said air mass, an acoustic wave, of which the direction of propagation ( 1 ) is essentially perpendicular to the direction ( 2 ) of displacement of said membrane ( 7 ).