Master recording engineer Tom Dowd presided over some of the greatest sessions of the 50s, 60s, and 70s, capturing classic moments in jazz (with John Coltrane and the Modern Jazz Quartet), soul (Ray Charles, Aretha Franklin), and rock (Cream, Derek and the Dominos, the Allman Brothers Band, Lynyrd Skynyrd). This documentary profile by Mark Moormann, begun in 1997 and completed shortly after Dowd passed away in 2002, is curiously placid at the center, mostly because its subject seems so genial and unconflicted compared to his tetchy clients. But Moormann pays careful attention to the development of modern recording techniques and the currents of the music business, providing a rich aesthetic context for the old man's colorful stories. Like most engineers, Dowd seems doomed to invisibility, but in this account, as in his timeless records, he's also omnipresent. 90 min.