The Collaborative International Dictionary of English v.0.48:

Aerophone \A"["e]r*o*phone`\, n. [A["e]ro- + Gr. ? voice.]
   (a) A form of combined speaking and ear trumpet.
   (b) An instrument, proposed by Edison, for greatly
       intensifying speech. It consists of a phonograph
       diaphragm so arranged that its action opens and closes
       valves, producing synchronous air blasts sufficient to
       operate a larger diaphragm with greater amplitude of
       vibration.
       [Webster 1913 Suppl.]