Five stars for being unexpected. When I come on POETV and see a guy with a gun and a title of "speech jammer," I'm expecting to see a demonstration by some guy with an arsenal of the mad science DARPA weapon the criminal gangstalking illuminati are using to make him not be able to form coherent sentences.
Kazutaka Kurihara's SpeechJammer which won the IgNobel prize, looks like a bit like a gun, with a pistol grip and laser target designator.
Given the speed of sound, its theoretically only effective out to 34 m (any more distant and the delay is too long). Given the design of the original SpeechJammer I doubt it works well past 10m. A parabolic mike and complementary directional speaker (phased array or parabolic) could make this more effective at, say, political rally ranges.
Imagine setting up the Podium from Hell by placing the stage monitors just far enough away to get this delay naturally, whoever tried to give a speech would think they were having a stroke.
So I just tried speech jamming myself with audacity and it's not so much of a problem if one can speak quick (not too quick) and with one's thoughts formed before one speaks. The issue is when speaking slowly and listening to one's voice to cue the set of words or thoughts to be conveyed.