When the Zac Brown began making music, his main venue was Zac’s Place, the restaurant he and his dad owned in Dahlonega, Ga. Brown and his band may now be playing such mega-amphitheatres as the D.C. area’s Jiffy Lube Live, but the award-winning bandmates still have the same do-it-yourself attitude they did 15 years ago when concerts were on the restaurant’s lawn and served up alongside southern barbecue.