Police in Chicago are preparing to deploy controversial sound cannons against protesters at the G8/NATO Summit next month. The so-called Long Range Acoustic Devices, or LRADs, emit painful and potentially harmful tones over long distances. The device was created for military use, but it was deployed against protesters for the first time at the 2009 G-20 Summit in Pittsburgh. The American Civil Liberties Union later filed a lawsuit on behalf of a bystander, Karen Piper, who said she suffered permanent hearing loss, while the American Tinnitus Association said Pittsburgh protesters had been "acoustically assaulted." They compared the sound pressure to what armed forces might face from an improvised explosive device. Massive numbers of protesters are expected in Chicago when the summit begins next month.