Warning: SPOILERS for Obi-Wan Kenobi episode 3.
The iconic James Earl Jones returned to voice Darth Vader in Disney+'s Obi-Wan Kenobi series, but there's a reason his voice sounds more like it did during Star Wars' original trilogy instead of the way it sounded in Rogue One: A Star Wars Story. Darth Vader is often heralded as one of the greatest movie villains of all time, and much of that designation can be attributed to James Earl Jones, who was brought in after production had wrapped on George Lucas' Star Wars film to record lines as Vader.
Darth Vader's armor, powers, and red lightsaber made him a force to be reckoned with, but to audiences, his voice and deep breaths made him a nightmarish villain. It's why no one's been able to replace James Earl Joens as the voice of Darth Vader for 45 years. He's even returned to voice the character in animated projects like Star Wars Rebels. So it's understandable that Lucasfilm would bring him back for Obi-Wan Kenobi, despite the fact that Hayden Christensen plays Vader himself. But there's one caveat here.
According to the credits for Obi-Wan Kenobi episode 3, the company Respeecher provided "voice conversation services." While it's not explicitly stated which character they worked on, it's undoubtedly James Earl Jones' voice for Darth Vader; there's no other character from episode 3 that they'd need to work on. What Respeecher does is augment new dialogue, or use existing dialogue from previous releases, to create a specific voice. This was used in The Book of Boba Fett to create a younger Mark Hamill voice for Luke Skywalker.
This is why Darth Vader sounds more like he did in the original trilogy because it's not James Earl Jones' current voice as it sounds in 2022. Notably, Rogue One didn't use the Respeecher technology and had James Earl Jones record new lines for Darth Vader's appearance in that film. It's unknown at the moment if he recorded the dialogue for the series and that dialogue was processed through Respeecher, which is most likely the case since James Earl Jones is outright credited for his performance as Darth Vader in Obi-Wan Kenobi episode 3.
Similar to the de-aging technology being used in various Disney projects - particularly Marvel and Star Wars movies and TV shows, like Nick Fury in Captain Marvel and Luke Skywalker in The Mandalorian and The Book of Boba Fett - the Respeecher service is becoming a more commonplace thing for iconic actors and roles. Lucasfilm recently stated that they're not interested in recasting major characters as they did for Han Solo in Solo: A Star Wars Story, so this technology will be heard more often than not in the future.
New episodes of Obi-Wan Kenobi release on Wednesdays on Disney+.
