Boston — National Public Radio listeners this week began welcoming into their homes dreaded Imperial Stormtroopers, a loathsome Mynock, and the biting chill of the ice planet Hoth. And liking it, too.
Recapturing much of the sheer grandeur and excitement of the movie on which it's based, ''The Empire Strikes Back'' (check local listings for episodes and repeats) will put another feather in the cap of NPR, a cap that's beginning to look like a headdress. Too, this 10-part series gives evidence that radio drama is not obsolete - it's just waiting for fresh productions and compelling stories.
Two years ago NPR offered ''Star Wars,'' based on the first of filmmaker George Lucas's movie series for which ''Empire'' is the sequel. Listeners bit, and the results were a startlingly high level of listenership (with about 95 percent of NPR stations airing the show) that helped lever a major boost in public-radio ratings at that time.
Now comes ''Empire,'' produced by NPR in association with KUSC-FM/Los Angeles and with the cooperation of Lucasfilm Ltd. It's a simple tale of good and evil. Wearing the white hats are the virtuous Rebels, a small group of fighters battling it out with the domineering black-hatted Empire and its evil Darth Vader.
Because of the popularity of its film predecessor, ''Empire'' must both recall the images of the movie, for those who have seen it, and simultaneously spin the tale for the uninitiated. On both counts, judging from the first six episodes made available by press time, ''Empire'' succeeds with zest.
The voices - including Mark Hamill as Luke Skywalker and Anthony Daniels as the robot See-Threepio, both of whom were in the movie; Perry King as Han Solo; Brock Peters as Darth Vader; and Ann Sachs as Princess Leia Organa - hoist the burden of their characters and carry them distinctively through these episodes. John Lithgow, who was not in the movie, embodies the mirthful impishness and wisdom of Yoda, Luke Skywalker's mentor, and deserves particular praise.
The script for radio, adapted by Brian Daley, leads listeners safely through danger and challenge without using baldly descriptive remarks by the characters.
But it's not simply the script - or the voices - that are responsible for ''Empire's'' success. The production's building blocks are the magnificent music of John Williams and the brilliant sound effects of Ben Burtt, both of which were completely re-edited for the radio-drama sound track.
''Empire'' uses approximately 1,000 different sound effects, as well as about three hours of dialogue (the movie only had 40 minutes).
To put the pieces together post-production supervisor and co-director Tom Voegeli used a 32-track digital multi-track recorder. Both he and director-script editor John Madden repeated the roles they played two years ago in the ''Star Wars'' radio drama.