Bill Hanley is regarded as the "father of festival sound". He is most widely known as the sound engineer behind the Woodstock festival in Bethel, New York in August 1969. He was also influential in a number of other festivals. According to Michael Lang about Woodstock, "“I was trying to find someone who could do a sound system for Woodstock, and there was no one who had ever done something like that before. Then there was this crazy guy in Boston who might want to take a shot at it.” He was also a part of the large rock Mar Y Sol festival in Puerto Rico in the 1970s.