The composer, author and performer died Sept. 13 of pancreatic cancer at his home in West New York, N.J., his wife, Nora Farrell, said.
Duckworth's compositions were highlighted by elements of Minimalism -- which included repetition, accessible harmonies, complex melodies and color dissonances, The New York Times said.
His 1978 series of 24 "Time Curve Preludes" is widely considered to be one of the first scores in the post-Minimalist style.
Duckworth incorporated the Internet and audience interaction in his later pieces. More than 5 million listeners visited the website for his 2001 project, "Cathedral," in which he streamed performances by ensembles from around the world live for a full weekend.
"The web is changing music, not only by offering a new set of tools and a new means of distribution, but also by shifting the focus of what it means to be musical," Duckworth wrote in his 2005 book, "Virtual Music: How the Web Got Wired for Sound."
Duckworth taught composition at Bucknell University from 1973 until his cancer diagnosis in 2011. He is survived by his wife and three children.