For the 24th year, MIX 104.1 is thrilled to treat the Boston community to a FREE live concert for all ages along the Charles River rain or shine.  The annual MIXFest concert, presented by Dunkin’ Donuts, returns to Boston’s DCR Memorial Hatch Shell on Saturday, September 16, with an impressive lineup of live performances. This year’s MIXFest features Kelly Clarkson, Blondie, and Andy Grammar.