The Pirate (1948)

2007 R1 Warner DVD: Somewhat muffled throughout, though a 3-minute sequence beginning 5 minutes in sounds significantly worse.

2007 R2 Warner DVD: Like the R1 DVD, but not identical.

2020 Warner Archive Blu-ray: A new mastering. It generally has a bit more noise reduction than the DVDs, but some sequences have less. Most of the dialogue-associated hiss has been attenuated (thoug not removed completely). Pretty similar overall. 

This was first released on VHS with a HiFi track in 1987 (clamshell) and then issued again in 1990. As none of the LaserDiscs have a PCM track, the tapes would plausibly sound the best.