8½ (1963)

The mono track on the 2014 Mustang blu-ray (based on the latest and otherwise best 2013 restoration from Italy's National Film Archive) is bloody terrible. Fortunately, it seems like Criterion's blu-ray, sourced from an earlier Mediaset restoration, was also made from the 'correct' materials once upon a time (it's missing just 6 frames of real filmic content), so although it looked dated even in 2010, its audio track sounds good -- audio restoration hasn't progressed much at all in the last ~decade and, thankfully, this track is a rare instance where Criterion didn't eliminate too much of the high-end.

The Criterion sounds a lot better, since Mustang (or possibly the 'restoration' team itself...) did do that (along with a high-pass filter), and rather aggressively. The Italian audio track on the Gaumont disc sounds slightly better than the one on the Mustang, but not by much.

Here's a 15 mb A/V sample (PW = asdf) with both tracks so you can flip between them.
You do not need bionic hearing to discern the difference!