The Black Dahlia asked more or less this question on Nov. 30, 2004, but I see no answer posted. There have been times, especially during the final episode of the 2004-5 season, when there were on the sound track some sounds that might be clues to the listeners solving this puzzle. OTOH, they might just be unusual instrumentation in the mood music. In other words, they may represent something "there" or be for our ears only. (I'll refrain from repeating Hitchcock's famous quip.)

Many of us (including Usenet discutants and one other person known to you) wondered particularly about a certain ratchet sound in a scene in which an unseen winch may have been operating. Can we assume that sounds like this are sound FX, or might they be part of the music?