Answer: Return of the Jedi

The third film in the Star Wars franchise did more than continue the epic space opera the first two had started. As the first film to use THX sound certification, Return of the Jedi advanced the quality of theater sound for all movies everywhere.

Many people think the THX sound, with its iconic logo and distinct “deep note” sound test that plays at the beginning of both movie theater films and home media alike, is a way of mastering and recording/reproducing sound (much like Dolby Digital). THX isn’t a way of recording sound, however, but a way of certifying that the playback of that sound meets certain criteria.

THX was developed by Tomlinson Holman at Lucasfilm to ensure the soundtrack for Return of the Jedi was accurately reproduced in theaters. Theaters certified in the THX standard meet architectural requirements (such as baffled and acoustically treated walls, floating floors, non-parallel walls, and a perforated movie screen for clear center channel sound) and pass sound system checks.

While the original intent of the certification process might have been to ensure that Return of the Jedi (and other future Lucas films) were shown properly in all their auditory glory, the standard raised the bar for all theater audio reproduction and we’ve been collectively benefiting from it every since.