The SE’s mixed Vader’s voice differently in both ANH and ESB. The 1997 SE of ANH has his voice mixed the same as the original but the 2004 DVD mixes it to where it’s a bit cleaner sounding than the original but very soft. For example during the dual with Ben his voice is almost drowned out by the lightsaber sounds. Sadly this is how Vader has sounded on every release since. Empire on the other hand amplifies his voice beginning with the 1997 SE and has remained so on subsequent versions.