An acoustic device includes first and second acoustic cavities which are air tight. A first passive radiator includes a first passive radiator diaphragm that has a rear surface which is exposed to the first acoustic cavity. A second passive radiator includes a first passive radiator diaphragm having a front surface which is exposed to the first acoustic cavity, and a rear surface which is exposed to the second acoustic cavity. A first electro-acoustic transducer is supported on the second passive radiator diaphragm. The first electro-acoustic transducer is arranged such that a first radiating surface of the first electro-acoustic transducer radiates acoustic energy into the first acoustic chamber and a second radiating surface of the first electro-acoustic transducer radiates acoustic energy into the second acoustic chamber.