The main credits state that the film's soundtrack was recorded using a 4-channel quadraphonic sound system. Sadly, there appears to be no evidence of it ever being exhibited in this manner.
A good U.S. version of this film has never been found. Only UK versions that are shorter with great quality. DVD releases of this movie have combined HD footage mastered from the 35mm negative with SD footage mastered from a U.S. release print of inferior quality resulting in significant shifts in image quality. You do get to see the entire extended version of the movie this way.
The plot and gimmick of scientists creating device to catch a spirit, entrap it in some containment, and then sealed it away. Would be the basis for the 1984 film Ghostbusters.