adj. loud and echoey, as if produced by a megaphone.
The Century Dictionary and Cyclopedia
Of or pertaining to a megaphone; of the nature of a megaphone; transmitted by means of a megaphone: as, a megaphonic message.
Word Usage
""Telephone Thing" sounds simulataneously dirge-like and vivacious, "Edinburgh Man" is sweetly melodic and atmospheric, and Smith's vocals - sometimes megaphonic, sometimes distorted - are a treat."