Sonic deception was performed by the 3132 Signal Service Company. By playing pre-recorded sound effects through speakers mounted on halftracks, they communicated the illusion of operating units moving during the night.
"All the sound and fury they heard was recorded. While they were waiting for our attack another division was crossing a few miles downstream against no opposition."
-Pvt. Victor Lawrence, Ghost Army Soldier (Dayton Herald, 21 Feb. 1946)
Sonic deception speaker (Photo: National Archives, c. 1945)
Halftrack with speaker mounted on back (Photo: National Archives, c. 1945)
The U.S. military first experimented with recorded sounds in 1942. After discovering records and other playback methods were unreliable, they developed state-of-the-art wire playback units, which played thirty minutes of recorded sounds that, when projected through powerful speakers, could be heard fifteen miles away.
Lt. Gilbert Seltzer describes how sound created visual illusions. (StoryCorps Interview/Ghost Army Legacy Project, 14 Jan. 2019)
Technology keyed sonic deception success. (Photo: Army Pictorial Services, c. 1944)
"After a while my eyes were beginning to tell me what my ears where hearing, and I began to see tanks."
-Lt. Dick Syracuse, 3132 Signal Service Company ("The Ghost Army," N.d.)