The Return of Godzilla (1984) has two main sound mixes: A seemingly earlier "A" mix, and a revised "B" mix with many alterations. The "A" mix is the only version released on home video in Japan, and its M&E assembly has been used as the basis for the majority of foreign language copies (additionally it served as the basis for the 5.1 remix). The "B" mix seems to have been created in tandem with or for a mono theatrical mix, which has never surfaced, unfortunately. The existence of a Japanese mono mix accompanying 16mm prints has been put forward on occasion, and the English and Cantonese mono tracks containing "B" alterations and different music edits support the possibility. The "B" mix was also used to create a special stereo version for a 1985 Drama LP release of the film. This list will cover the differences between the various mixes.
The "M" numbers correspond to the track listings on the Perfect Collection OST. It's also worth noting that in many instances, the export English dubbed track misses out or renders inaudible on a lot of incidental background foley heard mostly during dialogue scenes (e.g. the communications device sound effects at the beginning of the cabinet's discussion about the Super-X, Maki and Naoko running down the stairs in reel 6, etc.). I've cross checked these instances with the Cantonese mono dub/some parts of Godzilla 1985, and surely enough, they're clear as day in those.
- The mono recording of M1 has more prominently mixed brass (this is especially noticeable during the swell when the title card appears).
- The main titles originally had more subtle lava sound effects (they are almost inaudible in the English dub).
- More water sound effects are heard in the soundscape of Maki's introduction in the "A" mix. Yasuko Sawaguchi's Sayonara Lover fades out sooner as well.
- There is additional/differently mixed computer chatter during the scene at Hayashida's lab in the "B" mix.
- M7 goes slightly off-pitch towards the end of the scene in the mono "B" mix.
- M8 is off-pitch in the mono "B" mix.
- M11 is timed slightly different in the "B" mix. The sounds of the paper presses also are more prominent in the Drama LP.
- Alternate take of M12 is used in the mono "B" mix. This take is available on the Perfect Collection OST and can be heard here. Drama LP uses the regular stereo take.
- *Alternate, louder bird foley in the "B" mix (See also to this video)
- The first portion of M13 is tracked in earlier in the Drama LP.
- M14 is quieter and timed differently in the "A" mix.
- An alternate sound effect is used in the "B" mix for when Godzilla pulls out the reactor core (it sounds less metallic). The hissing of the escaping steam is also more prominent in the "A" mix.
- M16 is off-pitch in the mono "B" mix.
- M18A is tracked in later in the Drama LP.
- There is a change in volume in the rotor sound effects on the close up patrol helicopter in the "B" mix, while there is no such change in the "A" mix.
- M18B is tracked in sooner in the "B" mix. In the mono mix, it begins as soon as the shot of the dock comes up, but in the Drama LP, it begins even earlier during the preceding shot of the helicopter.
- The shot of the fighter pilot's cockpit exploding has an additional explosion sound in the "A" mix (the classic '50s-'70s variant).
- There is additional Russian dialogue aboard the Balashevo during Godzilla's attack in the "B" mix. Some of the clamoring aboard the deck is in the "A" mix, but it is deeply buried by music and sound effects. The other instance of additional voice work that also appears in Godzilla 1985 (during the shot of Kashrin stumbling below deck) is completely "B" mix exclusive, however.
- The stock scream heard during the shot of the soldier on fire is tracked in with a more abrupt beginning in the Drama LP. Furthermore, the screaming mixed under it is more prominent than in the "A" mix.
- The sound design of Godzilla's roasting of the port area fades out smoothly after the shot of the soldiers getting incinerated in the "B" mix, rather than coming to the abrupt stop heard in the "A" mix.
- M20 is off-pitch/timed differently in the mono "B" mix.
- M21 is timed much earlier in the Drama LP, as far as throwing off the score's normal synchronization with the action happening on screen. This cue is also slightly off pitch in the mono "B" mix.
- The Drama LP omits "Genzai..." from the shot of the police car blaring out evacuation instructions. This appears to be part of the "B" mix dialogue stem itself, since the truncated line also appears in the R2 5.1 mix and the Kraken DTS track.
- The composite shot of Godzilla advancing on the crowd in Nagatacho has no music in the "B" mix. When the music does resume, it is tracked in slightly earlier in the Drama LP compared to the mono mix.
- A different roar is heard for when Godzilla looks down on the bum at the restaurant in the "B" mix.
- The "B" mix lacks an impact sound effect as a laser cannon scores a hit on Godzilla.
- Alternate siren sounds are heard in the "B" mix as Hayashida and co. attempt to make their escape from the institute following the experiment. These are tracked in just as the Professor opens the door and runs out, while the "A" mix's equivalent starts earlier with the shot of Maki shielding Naoko from the debris. The "A" mix siren is then tracked in during the shot of the party running up the stairs to the roof, augmenting the "B" siren.
- M25 is timed and edited differently in the "A" mix, which repeats a bar before the Super-X appears from behind a skyscraper. Both mixes' respective edits of this cue both appear on the Perfect Collection OST. The Drama LP uses the "B" mix's edit, but times it earlier so the Super-X's flourish is no longer timed to immediately coincide with the craft's light coming into view.
- The "B" mix omits the first half of Godzilla's roar when the Super-X fires its first cadmium shell into his mouth.
- M27 is retimed in the Drama LP to make the dramatic crescendo coincide with the shot of the nuclear satellite launching its missile precisely. The missile's thruster sounds are also boosted in volume.
- No heartbeat sound effects at the head of the reel in the English track and Drama LP. The sound is heard in the Cantonese dub, however.
- Godzilla's breathing before he lets out a blast of his heat-ray has a smooth fade in the "A" mix, but an abrupt start in the "B" mix.
- M31 is timed differently in the "B" mix. The acoustics of this track seem to differ between all three mixes upon closer observation.
- M32 is off-pitch in the mono "B" mix.
- The distant siren sound effects heard during the wideshot of Godzilla, the Super-X and the crowd beneath them after the missile approaches are rendered inaudible by the clamoring in the "A" mix.
- The siren sounds in the following scene between Maki and Naoko are also mixed differently in the "B" mix.
- M33 is off-pitch in the mono "B" mix.
- The "A" mix skips The Awakening of the Giant Beast III (or M35B') entirely and uses M35C in its place. The timing of The Awakening of the Giant Beast II (M35) also differs between the Drama LP and the mono mix.
- M38 is missing in the "B" mix.
- The sound effects of the skyscraper crashing down on the Super-X do not fade smoothly in the "B" mix.
- Different roar used for the composite shot of the bum running from Godzilla in the "B" mix.
- There are additional destruction sound effects as Godzilla corners the bum.
- And most famously, Godzilla's wail only appears in the "B" mix.
Resources for documentation provided by Brian R. Culver/Allen Perkins and Steven Sloss.
*In the 5.1 remix, if you crank up the volume on the surround channels, you can hear the muffled remnants of the "B" mix bird sound. This seems to be buried in an early version of the mono foldown "A" mix M&E track as well, as the oddity is heard in the German and French dubs.