A man speaking through a bullhorn.
bullhorn definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a portable electronic voice amplifier
Origin: bull- plush horn
bullhorn definition by American Heritage Dictionary
A portable device consisting of a microphone attached to a loudspeaker, used especially to amplify the voice.