An acoustic passive radiator that controls "rocking mode" vibration includes a diaphragm for radiating acoustic energy. The diaphragm has a perimeter portion and a central portion. The perimeter portion is thicker than the central portion. The passive radiator further includes a passive radiator suspension. The suspension includes a skin element encasing the diaphragm. The skin element comprises a surround for physically coupling the passive radiator to an acoustic enclosure, pneumatically sealing the diaphragm and the enclosure. The surround has a non-uniform width. The passive radiator is a non-pneumatically sealing, non-surround, non-spider suspension element. The non-surround suspension element and the surround coact to control the the motion of the diaphragm and to support the weight of the diaphragm. THE MOUNTAIN, FRAMINGHAM, MASSACHUSETTS 01701-9168, UNITED STATES OF AMERICA U.S.A. BOSE CORPORATION 2579/DEL/2004 A 2579/DEL/2004 INDIA 2009-03-20T11:40:08Z 2007-02-09 2004-12-28 319252 H04R7/00 NA ROMAN LITOVASKY, JINGYI LIU, ROGER MARK, NACHIKETA TIWARI 2393 0 385 U.S.A. 2004-01-15 10/758336 2007-02-09 0 2UwGZ51o 2009-04-30T18:40:49Z 87348 ROMAN LITOVASKY, JINGYI LIU, ROGER MARK, NACHIKETA TIWARI 10823 BOSE CORPORATION