Hello,
I've seen a number of posts comparing audio differences between the initial 70mm and 35mm theatrical releases of ESB, and I think some posters are confusing changes made between the original 70mm and the subsequent fine-tuning for the 35mm release, with changes made in the remixing of the soundtrack for the 1993 LD transfer, or editorial changes for the Special Edition.
I've digitized the audio of the 1985 BetaHiFi pan-and-scan Dolby digital surround tape and compared it to the 70mm in-theatre recording and the 1993 transfer that was used on the 2006 bonus DVD. I found VERY few changes between the 70mm and initial 35mm releases, and hardly any between the 1985 and 1993 transfers.
Naturally I couldn’t compare visual changes suggested between the 70mm and subsequent 35mm releases, but the audio of the Wampa cave fight - prior to Luke using the force to retrieve his light saber - is about five-and-three-quarters seconds shorter in 70mm than the 1985 and 1993 transfers, so a comment that an additional shot had been added seems about right. The Bacta tank scene runs the same length in all three versions, so the visuals may match as well (despite my previous postings on that matter).
Below are the audio "differences" which I've pulled together from several postings, with my notes on the 70mm recording; 1985 pan-and-scan transfer (85PS); 1993 transfer; and the Special Edition (SE).
(I didn’t bother tracking other changes made specifically for the SE, like switched music cues or new footage, because I really don’t want to sit through the whole thing, it's that irksome.)
* * * * *
On Hoth, right after C-3PO tells R2 to "Switch off," R2 gives out a little "blurp." No "blurp" in 70mm; No "blurp" in 85PS; No "blurp" in 93; "Blurp" is in the SE
When Luke finally collapses in the snow, he lets out a grunt as he lands on his face. No grunt in 70mm; No grunt in 85PS; No grunt in 93; grunt is in SE
Luke says an additional "Ben… Dagobah…" just before Han says "and I thought they smelled bad on the outside." No additional "Ben…Dagobah" in 70mm; not in 85PS; not in 93; extra dialogue is in SE
The following dialogue is the same in 70mm, 85PS, 93 and SE:
ROGUE 2: Commander Skywalker, do you copy? This is Rogue 2. This is Rouge 2. Captain Solo, do you copy? Commander Skywalker, do you copy? This is Rogue 2.
HAN: Good morning. Nice of you guys to drop by!
When C-3PO tells Luke "It's so good to see you fully functional again," Luke replies "Thanks, 3PO." There is no "Thanks 3PO" in 70mm; not in 85PS; not in 93; extra dialogue is in SE
The line "Headquarters personnel report to Command Center" is repeated three times instead of two. Only 2x in 70mm; only 2x in 85PS; only 2x in 93; 3x in SE
When R2 is being loaded into Luke's X-Wing, C-3PO says the word "and" before saying "do take good care of yourself." "And" is heard faintly in 70mm; it is MUCH fainter in 85PS; I can’t hear it at all in 93; it is MUCH louder in SE
Han's line "Transport, this is Solo. Better take off, I can't get to you. I'll get her out on the Falcon" is followed by, "Come on!" No "come on" in 70mm; No "come on" in 85PS; No "come on" in 93; extra dialogue is in SE
In the asteroid field, after C-3PO says "Oh, this is suicide," he says, "There's no where to go." "There's no where to go" is not in 70mm; Not in 85PS; Not in 93; extra dialogue is in SE
Yoda makes a frightened "Ehhhhh!" sound just before Luke says "Like we're being watched" and points his blaster at him. No frightened "Ehhhh!" in 70mm: not in 85PS; not in 93; "Ehhhh!" is in SE
Yoda says the word "Run!" before "Yes. A Jedi's strength flows from the force." "Run" is in 70mm; "Run" is in 85PS; "Run" is in 93; also in SE
The following lines "But beware the dark side. Anger, fear, aggression. The dark side of the force are they. Easily they flow, quick to join you in a fight" are also much louder and clearer. The lines are softer in the 70mm, the 85PS and the 93; dialogue is louder in SE
The Imperial fleet establishing shot after the magic tree scene has a different TIE fighter sound effect. The same TIE sound effect is in the 70mm, 85PS, and in the English language track of the 93; the French/Spanish tracks of the Bonus DVD have a DIFFERENT effect - Why?; SE effects sound different too, but hard to tell because it also has DIFFERENT MUSIC
In Cloud City, after C-3PO says "That sounds like an R2 unit in there. I wonder if it…" he says "Hello?" only once instead of twice. "Hello" is said 2x in 70mm; 2x in 85PS; 2x in 93; only says "Hello?" once in SE
Before C-3PO gets shot, a different voice says "Who are you?" Line reading sounds same in 70mm, 85PS and 93; different actor's voice in SE
While C-3PO is on Chewbacca's back when they enter the carbon freezing chamber, the line "Now remember, Chewbacca, you have a responsibility to me, so don't do anything foolish" is louder and heard more clearly. Dialogue is soft in 70mm, in 85PS and in 93; a little louder in SE
During the duel, when Luke knocks Vader from the platform, Vader lets out an "ooooh!" instead of an "aaargh!" "aaargh!" is in 70mm; "aaargh!" is in 85PS; "aaargh!" is in 93; the "ooooh!" is in the SE
Lando's line at the end, "Luke, we're ready for takeoff." is a different take. This reading sounds identical in 70mm, 85PS and 93; it's a different take in the SE
Dialogue at end:
70mm:
LANDO: Luke, we're ready for takeoff.
CHEWBACCA: Growl.
LUKE: Good luck Lando. I’ll meet you at the rendezvous point on Tattooine.
LANDO: Princess we'll find Han, I promise.
LUKE: Chewie, I'll be waiting for your signal. Take care you two. May the force be with you.
CHEWBACCA: Growl.
85PS, 93 and SE:
LANDO: Luke, we're ready for takeoff.
CHEWBACCA: Growl.
LUKE: Good luck Lando.
LANDO: When we find Jabba the Hutt and that bounty hunter we'll contact you.
LUKE: I’ll meet you at the rendezvous point on Tattooine.
LANDO: Princess we'll find Han, I promise.
LUKE: Chewie, I'll be waiting for your signal. Take care you two. May the force be with you.
CHEWBACCA: Growl.
It appears the only major audio changes between 70mm and original 35mm are extending the Wampa scene, and the final scene (more dialogue and music to cover the added FX shots).
Apart from the mix-down from LCRS+booms to Dolby Analog Surround, only Reels 1 and 6 would have been affected in terms of revising audio tracks to match changes made to the internegative for the initial 35mm release after the 70mm debut.
Cheers,