The producer hunches over a mixing desk and confers with the sound-effects man: "What have you got for the submarine door? No, that's more like the gate of Doctor Doom's castle." Among the synthesisers, samplers and CD racks is a box of X-Men bubblegum, and suspended from the ceiling is a model of the masked webslinger himself, Spiderman. There is a label hanging from its ankle: "I was going to be an insurance broker until I met Dirk Maggs."
Dirk "Mr Genius" Maggs, as Brian May calls him, is the writer/producer/director/techno-boffin behind Spiderman. A graduate of such radio comedies as The News Huddlines, he has based his script on Stan Lee's Marvel Comics of the Sixties, with their blend of boyish wonder, gleeful daftness and soap-opera interaction: "The girl I want to marry is getting hung up over a homicidal Sub Mariner!" splutters Mr Fantastic, mid-battle. "Reed, not now . . ." tuts the Invisible Girl. Were any Archers fans to tune in, their eyebrows might also be raised at the adventure and the ground-breaking effects (and wall-smashing, bomb-exploding effects for that matter).
Maggs, in his own words, "late thirties, but eight years old at heart", is on a mission to expand the parameters of radio drama. "It's perfectly possible for the medium to build a world around you," he says, "to create a very full and layered picture. Just having two voices and no background noise is fine now and then for effect, but it shouldn't be the rule." And what better testing-ground for in-your-face radio than larger-than-life superhero stories? Maggs first adapted Superman for Radio 4 in 1990, then did Batman for Radio 1 last year. This was a hit, aided no doubt by knock-on publicity from Tim Burton's films, and a CD of the radio series topped the spoken-word chart. But the genre has its difficulties. It can't be easy to cast superheroes. "It's not," laughs Maggs. "American actors find it easier, I think. They have a wonderful sense of heightened reality."
Maggs orchestrates an exuberant cast who improvise, joke and seem bereft of Equity-issue egos. The show-stealer is Gary Martin, who plays The Thing, the man of stone. His voice is, well, gravelly. He croaks his way through Spiderman during the day and sings in Grease at the Dominion Theatre at night. But he risks typecasting - he dubbed the voice of a robot in Space Precinct, the latest series from Thunderbirds creator Gerry Anderson, and of a rock-chewing living mountain for The Neverending Story 3: "They ask you to do all kinds of things. They say, `Do you think you could give him an American accent, with hints of Polish and Russian? Oh, and remember that he weighs 60 tonnes. Now do his son, who only weighs eight tonnes.' "
Jonathan Kydd is another of the few British actors in the series. "The main problem is remembering which voice is which. I play the Green Goblin, one of the main villains, and I'm also Doctor Doom's henchman, who sounds quite similar. Then in the next scene I'm back as Steve, a character who had some lines two weeks ago, and I have no idea what he sounded like."
Like Peter Parker, Spiderman's mild-mannered alter-ego, Maggs' actors have to switch identities several times a day. In just five days, spread over a few weeks, they record 150 minutes of story packed with action and effects - a feat which would be impossible in TV or film.
"We're making movies here," says Maggs, "widescreen movies with special effects, Dolby Surround sound and orchestral soundtracks." One obvious difference is that Spiderman comprises 50 three-minute episodes, a format of which Maggs is tiring. "It has to hit the ground running every day. You want to convert listeners every episode so you need at least one fight or one great sound-effect each time. My ambition is to do an hour-and-a-half slot, bringing the layered-sound technique to bear on a thriller. You can do more than just comic-book stuff in this style. Radio should try to compete with the movies on their own ground soundwise. You could do The Terminator or Jurassic Park on the radio and they would work brilliantly."
Maggs is, to quote Stan Lee's Spiderman comics, a True Believer. His work is based on the idea that radio is closer to film than television is. Special effects which are too expensive for TV can be achieved on radio shows, with their audio-versatility and their listeners' imagination. The medium, Maggs thinks, has not been taking advantage of its own possibilities. "Radio should redefine itself. It has this attitude, `Oh, we're only radio,' and, `When are you moving to TV?' But it's not just a stepping stone. We can tell stories just as colourfully as any other medium. It's about time radio took a bite out of the bum of the TV industry. How's that for a quote?"
! `Spiderman' is on R1, weekdays, 4.20pm.