Remember the days before gangster rap when, instead of flowing like Eminem or Biggie, it was every suburban teenage guy's dream to rock? Way back, before

Remember the days before gangster rap when, instead of flowing like Eminem or Biggie, it was every suburban teenage guy's dream to rock? Way back, before all the self-inflicted angst of grunge and the irony of New Wave, when singers sang about demons and dragons, when people banned music for its satanic content, when you made devil's horns with your hands to show exactly how hard the music was rocking you?

Tenacious D, the comedy band featuring actor/musicians Jack Black and Kyle Gass, remember that era well. Indeed, the L.A.-based duo appears on the cover of their album naked beneath a huge winged demon, their acoustic guitars covering their privates. One notices immediately, however, that these guys look nothing like your average rock stars: Both are in a heavier weight class, and the bald one, Gass, looks like he might be more at home in a dentist's office than an arena. And, wait a minute — an acoustic guitar duo playing hard rock?

It's true, though — these guys are funny and they rock. Black, whom you probably recognize as the record store clerk turned singer in High Fidelity and the lead in the Farrelly Brothers' Shallow Hal, and the deadpan Gass began impressing club audiences around L.A. in the late '90s with their unique mixture of musical spoofing and brilliant potty humor. Within a few years, they had earned a spot on HBO's Mr. Show comedy series. And just recently, they've reached the next level: a full-length album (Tenacious D) with top-flight production and musician credits that include the Foo Fighters' Dave Grohl and Phish's Page McConnell. To promote it, they've been touring nationally, on their own and as an opening act for Weezer.

Like the best rock parodists, Tenacious D have real musical skills to back up their humor. Jack Black, as he revealed in High Fidelity with his version of “Let's Get It On,” has serious chops as a singer. His agile voice goes through different styles like a radio on search, skewering rock and metal singers both classic and new: a touch of David Bowie here, a bit of Robert Plant there, a Jethro Tull-like scat thrown in for hilarious effect. And Gass is no slouch on the guitar. Their music and lyrics meld Led Zeppelin-esque medieval nonsense (“every hundred thousand years or so/when the rain doth shine and the moon doth glow”) with the lewdness of stand-up comedy (their sensitive ballad is titled “F — Her Gently”.) The D spoof the bombast, ego and testosterone-charged spirit of rock as perfectly as Spinal Tap did in the '80s.

So what, exactly, is the D's creative process? And what is the recording technology that they used to create such songs as “Jesus Ranch” and “Exploding Brains”? “You want to know the secret?” Black asks. “You go down to Radio Shack, you get yourself a good tape recorder, top-of-the-line Radio Shack, I think it's called Optimus. You gotta get the one that records in stereo, and not the little guy. Get the big one. You press Record, and you just do whatever comes to your damn head, and you do it for hours. And it's gonna be all crappy, except for about one minute, maybe 30 seconds. And you stretch that 30 seconds into a song. And you know what you've got? I don't know. But that's our method — we just gave it out for free.”

For their major-label debut, however, the D needed more firepower than Radio Shack could provide. To produce the album, they hooked up with John King and Mike Simpson, aka the Dust Brothers, famed for producing such oddball sonic masterpieces as Beck's Odelay and the Beastie Boys' Paul's Boutique. “I had been a fan of the D for many years,” says Simpson. “I was doing A&R at Dreamworks, and I thought it would be a great idea to do a record with those guys. I wasn't so sure about how well a comedy record would do, but I just felt that based on the shows I'd been seeing, these guys were amazing songwriters, singers and performers, and I thought they could probably make a serious rock record.”

And what did the D think of collaborating with the producers behind “Devil's Haircut”? “We had the best guys in the business working on this friggin' album,” Black says. “They could make Shakira sound good. They could get Shaq O'Neill back on the charts.”

“They were kind of egomaniacal taskmasters,” Gass deadpans. “No, they were a lot of fun to work with. I've felt like we'd found our dopplegangers. John is kind of a Pro Tools wizard. He has a munchkin, elfin quality.”

For the album, the D decided to turn their acoustic rock parody into a full rock band sound, with drums, bass, synthesizer, electric guitars and the occasional strings. “We knew that there were a lot of bootlegs around that were just our live show,” says Gass. “So we thought it would be fun to blow it up a little bit in the studio. And the Dust Brothers really encouraged adding some stuff.”

“I suggested that we create a sort of supergroup,” Simpson says. “I said to the D, ‘You know, you guys have got a lot of fans out there, especially rock star fans, and I'm sure they'd be psyched to play on the record.’ And they were like, ‘Really? Do you think?’ And I was like, ‘Yeah.’ And they said, ‘Well, Dave Grohl asked us to be in his video.’ And I said, ‘Well, there you go, you've got a drummer.’” Initially, it was unclear if Grohl had time for more than a guest appearance on the album. But he exceeded all expectations by playing drums throughout, as well as doing some electric guitar overdubs.

The recording began with a two-day session at Neil Diamond's studio in L.A. They got the hook-up for the studio because Diamond had just appeared with Black in the film Saving Silverman, in which Black plays a Neil Diamond cover singer. “Diamond claims it was the Liberty Records studio,” King says. “It's a really old place.”

“It's like a '70s living room,” Black remarks. “Lots of brown shag carpets, lots of big posters of Neil. It was groovy; had a good vibe to it.”

“Neil was there one day,” Gass adds. “He had us work on a song that he was writing, and pretended that we were helping him, and we weren't at all.”

“I tried to lay down some harmony tracks,” Black winces. “Whoo-wee! Ixnayed!”

King and Simpson had the D play through their set live in the studio, with Grohl and bassist Steve MacDonald accompanying them. They used a minimal setup, as they were going only for drum takes. The drums were miked with a Neumann FET 47 on the kick, a Shure 57 on the snare and two Manley Reference Golds as overheads. They recorded MacDonald's signal direct through a Bass Pod Pro to avoid leakage.

“We had sent Dave and Steve CDs of the songs,” John King says. “Dave came in and we worked for one and a half days. In the equivalent of one day of studio time, Dave played drums on 20 songs. And it was fully improvised. They'd run through it, and he'd come up with something, and we'd do anywhere from one to five takes. I took all the drums, loaded them off analog 24-track, pulled them into Pro Tools and edited together a comp of different takes he had done — all my favorite drums and fills, things to accentuate the emotion and feeling of the song, and rock the most. We didn't use a click track either, so it was fully human time, human rhythm.”

What was it like for the D, who had never had a backing band, to work with the former Nirvana-ite? “Shredmaster 5000,” Black says of Grohl. “That's the first thing that comes to mind.”

Once they had Grohl's drum tracks, the Dust Brothers returned to their own studio to complete the album. Nicknamed “The Boat,” the studio was built for use as an organ chamber in the '40s. “We purchased it a couple of years ago and renovated it,” King says. “It's got a great big live room, nice iso booth. In our main control room, we have a vintage Neve full of 1073 and 1066 mic pre EQs. We've been told that it was one of George Martin's Neve boards from Air Studios in London, from the '70s.”

In The Boat, the D proceeded to kick out the jams some more, including the songs “Keilbasa,” which features some of the best phallo-comic metaphors since Spinal Tap's “Big Buns” (“I check my dipstick/You need lubrication, honey”), and “Karate,” which features conflict-resolution Jack Black style (“You broke the rules, now I pull out all your pubic hair”).

“He's a great vocalist,” King says of Black. “The thing about Jack is, he goes through so many vocal styles. That can be a little hard on his voice. He tended to want to kick out five takes max. I wouldn't do a lot of warm-up, or spend a lot of time getting the mic sound. I wanted to capture his voice on that second take, when it was just perfect.” King used a vintage Neumann U47 for all of Black's vocals.

The album was actually mixed twice, once by the Dust Brothers and a second time by Ken Andrews, both using an SSL board. “When we went in initially, Jack and Kyle were really concerned that they could hear their acoustics,” King says. “So we did the mixes like that, which was tough, because for rock songs, usually the acoustic is not the most dominant instrument. I really liked the sound of them. It's not pumpin' rock, but it's like this California rock, pre-Eagles era, early '70s, when there was a lot of folksy elements, and it sounds like nothing else out there.” However, Andrews' mixes, which ended up on the album, have a more traditional rock sound, emphasizing the electric guitars, bass and drums. And in the words of one D song, they truly “rock your socks off.” Not bad for a couple of guys who, by their own admission, don't play electric guitar.

“Sound will come out of the amp, but it won't be any good sounds,” Black says.

“I'm gonna work on that this summer, and then in the fall, I'm gonna take some classes,” Gass adds.

“With who?” Black asks.

“Uh, I don't know. Yngwie. Or Joe Satriani.”

“Satriani actually teaches. I don't know if Yngwie does.”

“Well, I just watch. I'm gonna get some videos, check 'em out at home.”

Whether or not they ever learn to play electric, the D will never stop rocking — or amusing. “These guys are ‘on’ all the time,” Simpson says. “Every day we got our own private Tenacious D show.”

Do the D have any final words of rock wisdom to impart to our readers? “For those about to mix,” Black sings, Angus Young-style, into my phone's receiver, “we salute you!”