The sonic modulator was a human-built sonic device. It could cause physical pain and injury by emitting powerful sonic waves. Toshiko Sato, an employee of the Lodmoor Research Facility, stole plans for the device at the order of a mysterious woman named Milton. She offered a working device from the plans in exchange for the life of her kidnapped mother. Jack Harkness said the plans wouldn't have actually worked, but with her technical genius, Tosh altered the design so that it did work. Before her capture by UNIT, Milton reneged on the deal, testing the modulator on Tosh's mother, aurally torturing her. (TV: Fragments)

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