High Quality Content by WIKIPEDIA articles! Large Professor (born William Paul Mitchell on March 21, 1973, in the Harlem section of New York, New York. USA), also known as Large Pro and Xtra P, is a New York City-based hip hop record producer and emcee. He is also best known as a founding member of the influential underground hip hop group Main Source, and as a frequent collaborator with Nas.About.com ranked Large Professor #5 on its Top 50 Hip-Hop Producers list.