It’s true that Dolby A decoding may not be the whole issue, or only part of it. Primitive A/D conversion could have altered the sound of the top end, and EQ adjustment could have been done to make it sound better on small tv speakers.

For Jedi at least, and I believe for Empire too, restoring the frequency balance of the early LD’s to match print audio can be done with a single shelf filter. A 10 dB reduction at 10 kHz gets it remarkably close, so it may be that this is all that was done to them.

For the first movie, it seems to be more complicated than that. Dolby A decoding is rather finicky, requiring the signal to be input at just the right level – a calibration tone on the tape at 0 VU indicates what level is needed. If the level is set incorrectly, the decoder will either remove too much top end, or not enough, and it may also produce other artifacts since the decoding is a dynamic process that varies by how loud the input is. Fluttering distortion in the low frequencies seems to be the most obvious problem that can result. Such distortion can be heard at times in the print audio, so even properly decoded audio apparently isn’t completely immune to it. Obviously the laserdiscs do not have a calibration tone included, and so it is quite difficult to say how much level adjustment would even be needed to decode them. For that reason, EQ is going to give better results overall (along with digital noise reduction if needed), as schorman said.

@You_Too: Most of the EQ that I’ve done for these projects has used iZotope’s matching function as a starting point, with subsequent adjustment as needed. It really is a fantastic tool for this kind of thing! For music projects I love my Universal Audio stuff, but for Star Wars, iZotope is pretty much essential.