In January 1920, inventor and radio pioneer Lee DeForest brought her to the cramped studio of his station, 2XG, located in New York City's World's Tower, where De Leath broadcast "Swanee River". Although not, as is sometimes stated, the first broadcast of live singing, she established herself as a skilled radio performer, and De Forest would later note: "She was an instant success. Her voice and her cordial, unassuming microphone presence were ideally suited to the novel task. Without instruction she seemed to sense exactly what was necessary in song and patter to successfully put herself across". According to some historical accounts of this incident, having been advised that high notes sung in her natural soprano might shatter the fragile vacuum tubes of her carbon microphone's amplifier, De Leath switched to a deep contralto and in the process invented "crooning", which became the dominant pop vocal styling for the next three decades.