BAR HARBOR — Acoustic Americana virtuosos Mr. Sun will be joined by visual artist Alex Rheault for live music and artmaking at College of the Atlantic on Friday, Oct. 18. Mr. Sun comprises some of the most original musicians to apply themselves to the American string band: renowned fiddler Darol Anger, professor emeritus at Berklee College of Music who has released dozens of influential solo albums over a 50-year career, in addition to his work with David Grisman and Mike Marshall; Joe K. Walsh, mandolin virtuoso and vocalist who spent four years with the award-winning bluegrass act the Gibson Brothers before becoming a solo artist, songwriter and strings department professor at Berklee; all-around guitar genius Grant Gordy, a former member of David Grisman’s band and respected solo artist and educator; and the Scots bassist Aidan O’Donnell, who has backed harpist Maeve Gilchrist and countless modern jazz heroes.