After devoting more than 15 years to building their unique fusion of edgy performance and advanced yet home-brewed technologies, the Blue Man Group moves aggressively toward the mainstream with The Complex. "Mainstream" is, of course, a flexible notion, so what passes as commercial for these guys is a lot more adventurous than most of the era's ear candy. These tracks adhere to clear song structures, with guest vocalists singing actual lyrics on original as well as cover material; a zombie-like cameo by Dave Matthews on "Sing Along" offers the wryest surprises. But an unmistakable imprint endures in the eclectic sonic references and, above all, thundering stage-oriented rhythms. The core members of the group play traditional instruments -- in this case, ranging from standard-issue electric guitar to Hungarian cimbalom, heard most clearly in the opening seconds of "Above" -- as well as their invented gear whose contributions to the din are, frankly, neither critical nor easy to discern. On their version of the disco classic "I Feel Love," for instance, the 16th-note pulse created via sequencer for the Donna Summer original is mimicked by the device they call the Tube, giving rise to the question of whether using something new to do what someone else did with old stuff 20-plus years earlier is worth the effort. But this is, of course, beside the point: Although its inspirations, musical and conceptual, trace as far back as Kraftwerk, The Complex serves as a reminder that modern