The 1993 mix may be closely derived from the 70mm mix, but it also has some new elements in it, such as the explosion just before 3PO enters the escape pod. The sound of the asteroids flying past the Falcon are certainly from the 6 track mix, though. I'm not sure where the bass on the 1993 mix was derived from, but I don't think it was the baby boom track from the 6 track. That may all be new for the 1993 track, too.