Rome, Open City (1945)

The audio for the 4K restoration was derived from the original sound negative, so one should expect it to sound better than the tracks on any previous home video release.

And it does, but the differences aren't terribly dramatic. The most significant improvement it offers over the Criterion DVD is with its bass frequencies: the Criterion DVD doesn't really have any, while the BFI blu-ray has an at times astonishing amount. (The Italian 'Flamingo' BD, presumably sourced from some battered nth generation print, isn't worth discussing -- it sounds considerably worse than either).

Is some of this bass artificially accentuated? Perhaps -- there's an odd sort of diffuse rumble now present at all times -- but the true 'new' detail present is undeniable. 

The Criterion DVD is made even thinner sounding as a result of its slightly emphasised high-end. Everything sounds slightly harsher, while the BFI blu-ray sounds sweeter at these registers (through no fault of noise reduction -- I hear none, at least in the conventional sense: the lack of any real information above 9 kHz is odd).