PREVIEW How do you tell a fiddle from a violin? No one cries when they spill beer on a fiddle. From Ireland to Scotland to Appalachia, the hearty fiddle followed the common folk wherever they settled. In pubs and on back porches, fiddle tunes trickled down through generations, learned by ear from fathers or friends. Styles evolved within the regional confines of community, variously emphasizing and echoing chosen parts of the homeland's repertoire.
The 20th Annual Fiddle Summit reunites three fiddle masters from different styles under one roof: Alasdair Fraser, a Scottish fiddler, his bow heavy, his sound as thick and peaty as his brogue; Martin Hayes, an Irish fiddler with a high-lonesome, lilting style, his tempo wistfully stretched and yearning; and Bruce Molsky, an Appalachian fiddler, his sound percussively bright and bouncing, his melodies drawn chordally across multiple strings. Though each will showcase his own style for a set, the three end the show together, embracing the commonalities of their instrument and the debt each mode owes to the others.
As the opening night act for the Downtown Berkeley Music Festival, the Fiddle Summit is but one course in a brilliant banquet of sound. That morning, organist Will Blades and drummer Scott Amendola's dueling solos will offer a gratis mind-blowing at high noon on the Downtown Berkeley BART Plaza on Shattuck at Center. On Sunday, Chad Manning plays what the fiddle summit forgot: a set of bluegrass, Texas-style, and swing fiddling at Jupiter (2181 Shattuck), where you can try for yourself to tell a fiddle from a violin.
20TH ANNUAL FIDDLE SUMMIT AT THE DOWNTOWN BERKELEY MUSIC FESTIVAL Thurs/21, 8 p.m., $22.50. Roda Theatre, 2015 Addison, Berk. (510) 548-1761, www.downtownberkeleymusicfest.org  Festival continues through Sun/24, see Web site for details.<