Wiktionary
megaphonic
a. 1 Of, or pertaining to, a megaphone 2 (context of a sound English) Produced by a megaphone 3 (context of a voice English) loud and echoey, as if produced by a megaphone.
Usage examples of "megaphonic".
Too, it might be noted that many dramatic masks have megaphonic devices built into them which tend to amplify the actors' voices.