In guitarist Phil DeGruy’s parallel universe, Madonna gets nasty to “The Sound of Music” and Robert Tilton rules.

He’s describing “dubbing” -- a signature blend of music and performance art which the New Orleans musician will present on Wednesday, February 17 during his annual Mardi Gras gig at the Howlin’ Wolf.

In his show, DeGruy sits alongside a large-screen television and, like a cross between Joel Grey and a late-night movie host, presides o...