Okay thanks. I don't know how the ticket process works, but for anyone interested in looking into this bug, all of the high definition trailers on
http://www.apple.com/trailers contain AAC 5.1 audio. Just plug in your speakers into the analog audio out of your computer/sound card and what you hear is mostly the centre channel audio, i.e. mainly dialogue with little to no bass, sound effects, or music. Check out the excellent X-Men 3 trailer as an example. Thanks!