(timbre) ". . . in the opening sequence of Rouben Mamoulian's Love Me Tonight, people starting the day on a street pass a musical rhythm from object to object--a broom, a carpet beater--and the humor of the number springs in part from the very different timbres of the objects." (in the section "Timbre")
(frequency; timbre) " In The Wizard of OZ the disparity between the public image of the Wizard and the old charlatan who rigs it up is marked by the booming bass of the effigy and the old man's higher, softer, more quavering voice." (in the section "Timbre")
(manipulation of diegetic/nondiegetic relation) "In American Graffiti, a film that plays heavily on the distinction between diegetic and nondiegetic music, offscreen sounds of car radios often suggest that all of the cars on a street are tuned to the same radio station." (in the section "Resources of Diegetic Sound")
Link to Film Art on Bordwell's website: David Bordwell. And to the publisher: Film Art, 8th edition (this link goes to a table of contents).