Strategically placed with the right degree of persistence and 'sympathetic vibration', sound can reveal itself as a potentially devastating force. As used against the Branch Davidian religious sect in 1993 at Waco Texas, the FBI's little remembered 'sonic assault' - involving Tibetan monks in prayer, dentist drills, and other bizarre recordings - arguably contributed to the tragic denouement of events as they were witnessed live on TV by millions around the world. The use of sustained, high-pitched, loud or repetitive noises and music added to an already incendiary narrative endgame, established first by the sect but later supported by the media. This essay draws on this tragic event, and later 'forensic' research conducted by the author in the process of writing, scoring and producing an audio performance work, Cantata of Fire. Specifically, it explores the way in which amplified 'concrete' sound and electronic 'viral' voices were used as a weapon at Waco - materially, psychologically, theatrically and 'diegetically'. And in the context of a much longer (and repressed) history of sound as used in 'theatres of war' and other conflicts, the author reconsiders the overlooked and underestimated powers of sound, music and noise in an age dominated by digital 'real-time' electronic media and 'tele-visual' surveillance.