Barbershop singing has been around for so long that, according to Wikipedia, we’re still technically in a barbershop “revival” period which began in the 1940s. (It seems Wikipedia measures barbershop’s lifespan much like climatologists measure ice ages.) One thing about tight, four-part a capella harmony, though – very little overhead. Which is why this Saturday, for fifteen bucks (ten for seniors and students), you can catch a bill of six different a capella groups at Zion Lutheran Church, including Delta Harmony Xpress, a 25-member group based in Stockton that are making their concert debut. (FULL STORY: Tony Sauro, Stockton Record)