Few have shaped the sound of popular music as pervasively as the late engineer and producer Tom Dowd. But although interviews with former clients including Eric Clapton, Gregg Allman and Ray Charles paint Dowd as an affable perfectionist, they?re light on insight and anecdote. The Film skims the epochal sessions (Aretha Franklin, Cream, Otis Redding) but omits the like of Wilson Pickett and Charlie Parker. Dowd had many stories to tell; too few are here.