*Audio differences:
The nine 70mm prints contained a 6-track Dolby mix that was considered
unfinished. When the properly cut prints were made, both 70mm and
35mm, they went into wide release accompanied by finished soundtracks.
BUT, Dolby Stereo prints of the time were not mono-compatible as they
are now, so sound designer Ben Burtt created a totally different
monaural sound mix for 35mm, knowing that there were not many stereo
theaters at the time. In my experience, this mix got its widest
exposure during the "extended first run," which is erroneously (though
widely) referred to as the "1978 reissue."
The "Story of Star Wars" narration record was made using this
different sound mix (with stereo sound effects laid over it); in it
one can hear some of these differences.
The echo at the chasm is only on the stereo mix, by the way, and
it must be played back in stereo in order for it to be heard. It
cannot even be heard on a Dolby print played in a mono theater or on a
laserdisc played over a mono television monitor.
Threepio's lines ("The tractor beam is coupled...") were added
back into the home video sound master in 1986. For the recent boxed
set laserdisc, a new soundtrack was created for ANH, incorporating all
of the above. Oddly enough, Threepio's lines were left out once again!
Between Ely2B's post and my other informant's list, I put together the
following list of audio variations between the original release and
the recent laserdisc version:
1) Alarms and klaxons are different.
2) Added panel sound effects aboard the Falcon, including a descending
whine as they come out of hyperspace.
3) The communications to Tarkin via comlink are completely different.
4) When Threepio and Artoo are hiding from the Imperials on Tatooine,
the stormtrooper's dubbed voice is different, and so is the line:
Laserdisc:
"All right, check this side of the street. The door's locked. Move on
to the next one."
Pre-ANH video:
"All right, check that side of the street. It's secure. Move on to the
next one."
5) A different actress dubs for Aunt Beru. Neither version features
the real voice of actress Shelagh Fraser, who has a thick British
accent.
6) Some Threepio dialogue uses different takes. The additional lines
("The tractor beam is coupled to the main reactor in seven locations.
A power loss at one of the terminals will allow the ship to
leave....") are missing from the laserdisc version.
7) The echo in the core shaft ("I think we took a wrong turn...") is
present in both versions. However, the echo is more pronounced in the
laserdisc version--probably because the video is missing the surround
channels.
8) The laserdisc is missing the now-famous "Close the blast doors!"
line.
9) Intership voices during the final battle are not synthesized.
10) During the final battle, "countdown" voices on the Death Star and
at the Massassi base on Yavin IV are completely different.
11) Luke's line on the laserdisc, "Blast it, Biggs. Where are you?" is
different on the pre-ANH video: "Blast it, Wedge. Where are you?"
(from the collection of Peter Poulakakos).