"STAR WARS" and "The Empire Strikes Back" are radio drama of an ilk that's never been done before, sort of blockbuster radio, if you will." Tom Voegeli, codirector and postproduction supervisor on both projects, is still buzzing from his cramped Minnesota studio, where he is wrapping up the last of 10 chapters in National Public Radio's second installment of the George Lucas epics. (It kicked off last weekend on WETA-FM.)

The original "Star Wars" turned out to be one of the highest rated radio dramas of all time . . . and a tremendous audience builder for NPR. It featured not only a strong cast (including Mark Hamill and Anthony Daniels reprising their Luke Skywalker and C-3PO roles) but also the award-winning sound effects of Ben Burtt and musical score by John Williams. "It had such mass appeal that people tried to find it in their local market even if they didn't normally listen to NPR," Voegeli says. The 13-part series increased listenership as much as 40 percent in some areas, and a toll-free number elicited as many as 75,000 calls a week. "It was incredibly successful for public radio, which at times is the best-kept secret in the country. 'Star Wars' and programs like it are beginning to break that mold a little bit."

For Voegeli, the good news is that " 'Empire' is 10 times better radio. Brian Daley's scripts are better, which has to do with his learning a lot about radio and being more confident, consulting with the people who put it together. And the scripts are stronger because we used only 10 episodes. Broadcasters tend to work in increments of 13 because of 'quarters.' 'Star Wars' had 13 episodes, so the script had to be extended; this time there's a little less fat."

Each of "Empire's" 10 episodes took about a month to finish and cost about $30,000, which in radio terms is very expensive. "In television terms," Voegeli says. "They're less than three days of local Eyewitness News."

Lucas' film has about 40 minutes of dialogue, while the radio series, to compensate for absent visuals, has more than 210 (out of 300 minutes of air time). "In radio drama a scene generally takes about twice as long as in a film. It's totally instinctual. Some scenes tend to be more radiophonic, to work better as radio, so they get expanded more than the scenes that we really can't match--the battle scenes, the really big action scenes.We add just enough dialogue to advance the story in radio terms."

The entire production benefited from Voegeli's close relationship with three-time Academy Award winner Ben Burtt. "My little studio here has become kind of Lucasfilms Audio East and that certainly facilitated the production. Although the voice recordings only took 10 days, "Empire's" post-production for radio was almost as lengthy as it was for the film (150 days versus 180 days)."We had access to all the original sound and music components. The music was the original tapes recorded in London with the London Symphony Orchestra before they'd been edited by anybody else."

And then there was Burtt's vanguard sound effects library (the radio series uses more than 1,000 individual sound effects, about the same as the film). "I built the sound for each scene in the radio series in a very similar way to how Ben would approach it for the film. The sounds aren't all sitting on one recording--I have to built them back up from his original development sound effects. For instance, with a light saber, the effect has to be choreographed to the dialogue and to the music and it can be made up of lots of little pieces--the light saber igniting, the light saber swishing slowly, swishing quickly, hitting something, being turned off, that kind of thing. They're all separate sound effects put together for the radio series for that particular scene."

Voegeli is already anticipating a radio version of the upcoming conclusion to the Lucas trilogy, "Return of the Jedi" ("having put this much effort into it, I'd like the story to end"). He also worked with Burtt on a record version of "Raiders of the Lost Ark," and there's talk about an NPR series of that mighty adventure. "That would be a lot of fun to do, turning a B movie into a radio series. In that case we'd probably use narration because the comparable convention in radio of that time was the narrator-voice over. You could capture what Lucas and Spielberg were trying to do, loving the B movie and that form but using all the bells and whistles of contemporary filmmaking. What are the classical and wonderful conventions of radio drama that we could lovingly use?" The wheels begin to turn.