Complex sentence: Keith was locally famous in New Orleans as an ambient noise artist, member of the band, Manchild, and co-founder of Noizefest with local producer, Sir Stephen, which serves as an alternative, modern addition to the Jazzfest festivities.
Split into simpler sentences: Keith was locally famous in New Orleans as an ambient noise artist and member of the band, Manchild. In addition, Keith co-founded of Noizefest with local producer, Sir Stephen, as an alternative, modern addition to the Jazzfest festivities.