Even though die-hard fans of the movie have been practically begging Fox to release a version with the original mono soundtrack, they haven't listened. This has to do with marketing. This sound mix is every video release since 1990 in the U.S., and also since 1990 on new prints of the film. Dubbing over of the stereo track sometimes cuts sound effects and dialogue. Magenta's hissing at Brad and Janet during the Time Warp is missing.
Unnecessary sounds are present throughout the entire film.
The saxophone that plays throughout the mono version is cut off until the very end of the song. Obviously from the soundtrack album. Again, from the soundtrack album. Again, the entire chorus is on the right-hand side. Right after that, you can year the original mono chorus, which sounds very different from the stereo version.