The problem with most jazz documentaries is combining talk with music without allowing either to ride roughshod over the other. Peter Bull’s recent feature about Thelonious Monk disciple and soprano saxophonist Steve Lacy is a stirring object lesson in how to do this without compromising either the performances of Lacy’s inventive sextet or the interest in what Lacy has to say about his career. The mesh isn’t quite so fine in Ken Levis’s short about another postbebop saxophonist. Jackie McLean has some acute things to say about politics, racism, and the music business, but it’s a drag to hear them interrupting his solos; only in an outtake from Shirley Clarke’s The Connection is he allowed to stretch a little. (Film Center, Art Institute, Columbus Drive at Jackson, Sunday, August 23, 6:00 and 8:00, 443-3737)