Steve Vai is one of instrumental hard rock's most technically dazzling axemen, but what ultimately sets him apart is his ability to bridge brainy eccentricity with passionate songwriting. His early-'80s stint with Frank Zappa taught him how to elegantly navigate writhing art-rockers (“Bad Horsie”) and he can also do angelically crying ballads steeped in mysticism (“For the Love of God”). Vai has a silly streak too, best captured in the talking opening of “The Audience Is Listening,” a trick he perfected during his tenure with pop-metal gymnast David Lee Roth.