Dreaming up Caviar, the Chicago-based alt-pop quartet, didn’t require market research, complete with pie charts and demographic analysis.

It came to singer-guitarist Blake Smith and bassist Mike Willison in a simultaneous flash of genius during a trip to London last year.

“The band, in scope, was planned standing on a Tuesday in London at the Camden Palace listening to a song and we both looked at each other, we knew what we were going to do,” Willison said recently. “I don’t remember the song, but it might have been ‘U16 Girls’ off the first Travis record. We obviously don’t sound like that, but it was something about where we were and the inspiration that the whole trip had on us. It all hit us at once.”

Caviar and its self-titled debut Bomb Trax/Island album (released last month) isn’t some hoity-toity appetizer. With its DJ-influenced pop-funk grooves and Beck-meets-Lemonheads melodies, it’s a full-course meal, requiring the most open-minded of palates.

It doesn’t get any quirkier than “Tangerine Speedo,” the album’s leadoff single. Awash in recurrent triplet beats that would send Charo into a frenzy, the song makes light of a Latin lover who thinks he’s God’s gift to women but turns everyone off with his fashion sense.

“Oddly enough, we didn’t think that that was what it was going to sound like,” Willison said, laughing. “We didn’t think it was going to sound like a novelty hit. We thought it was going to be great. It is a good song, but it ended up being a little jokier than we thought it was going to be. That’s just where the song took us.

“Writing that song was so fun, I can’t even tell you. We record everything preliminarily in my apartment, and my girlfriend was sleeping in the next room and she didn’t feel good. It took us a whole day to cut those samples, like the cha-cha-cha’s, and figure out what speed we were going to put them in.

“We were driving her crazy. She walks in and says, ‘You have to be kidding me?’ She says, ‘You know what? I hate you, that song is a hit. I absolutely hate your guts for doing this to me, that’s going to be a hit.’ People either love it or hate it, which is fine with me.”

Believe it or not, there really is a tangerine Speedo guy.

“It’s kind of based on a true story that unfortunately I didn’t get to witness,” Willison said. “Blake went to Costa Rica over New Year’s because he thought something horrible was going to happen in Chicago (during Y2K). He wanted to be as far away from a big city as possible.

“The first day in Costa Rica, they rented horses and their guide was the tangerine Speedo guy. He wore only a tangerine Speedo all day, with no shirt or anything. They thought, ‘All right, that was a great day, and we’ll never see him again.’ But every single day, everywhere they went, they saw that guy and that’s what he was wearing every day … and at night. He’d be chatting up some French girls in a bar and that’s all he was wearing.”

Surprisingly, radio listeners who normally have discriminating tastes are eating up the track. It’s at No. 36 on Billboard’s modern rock tracks chart and recently KROQ in Los Angeles added it to its playlist.

No one’s more shocked than Willison, Smith and band mates David Suh (guitar) and Jason Batchko (drums). Willison and Smith are former members of Fig Dish, a fat-chords alt-pop band that cut a memorable album for Atlas Records in 1995 (“That’s What Love Songs Often Do”). After Fig Dish ran its course, the two were left to ponder their futures.

“Fig Dish was a product,” Willison said. “It was something that came out of three guys writing every song. Someone would bring an idea – Blake, Rick (Ness) or myself – and the whole band would apply themselves to it in a certain way. There ended up being a Fig Dish feel, and it was one guy, Rick, an unbelievable guitar player and a music theorist. When he would apply his guitar knowledge to songs, it was like ‘This has to go this way, this is the mathematical and musical way it works.’ Whereas Blake and I, who are absolute morons as far as theory goes, would go ‘Whatever, let’s go to this.’ Fig Dish was like bubble-gum grunge. It was loud guitars, but it was pop. We loved the Lemonheads at the time.

“When we started Caviar, we had a definite plan. We knew exactly what we wanted to do, as far as like a theory. We didn’t necessarily mean for it to sound different from Fig Dish, but because it was just the two of us, it was going to sound different anyway.”

After their revelation in London, Willison and Smith decided to go for broke … and they nearly did go broke.

“The thought was, ‘Let’s do this. We don’t care what it takes. Let’s get it done,’ ” Willison said. “We each borrowed like $10,000 from our dads, who we thought basically were going to say ‘Look, you’re getting too old for this. You’ve been screwing around.’ We both have master’s degrees in English, and it’s like, we should probably get to work and do something. We thought, this is it, if it doesn’t work, forget about it. We decided to put it out ourselves, we thought we’re never going to get signed, no one wants to sign a pop band, and we don’t sound like the Cookie Monster screaming into a microphone.

“We spent our money in like a week and realized we didn’t have anymore and we needed it. A friend of ours, Paul David Hagar, said he would mix it for free if we could get the tapes done and come down to Nashville. He had worked with the Dixie Chicks and full devil jacket. Him doing this for free was amazing. When he finished, he sent it off to someone at Island and they loved it. Next thing I know, they’re putting our record out. We took the chance, we hung ourselves out at the end of a tree branch and somebody plucked us off.”

They even paid back their fathers … well, sort of.

“My dad asked me to only pay him back half, and then when I started to pay him back, he said, ‘Ah, forget about it,’ ” Willison said.

The rest of the “Caviar” album isn’t kitschy like “Tangerine Speedo,” but it definitely turns conventional pop on its ear, particularly “Flawed Like a Diamond,” “Look So Hard” and “Sugarless,” the latter of which appeared on the “Gone in 60 Seconds” soundtrack album.

Willison doesn’t know if more people will bite into Caviar, but he sure hopes they do.

“I’d love to sit here and tell you that I know it’s going to go triple-platinum, but I never think it’s going to be that big,” he said. “I’m surprised at how many records we’ve sold, because I don’t know that many people, like my mom can’t afford to buy that many records. And that’s what surprises me, that other people have bought it. I would love to hang up a gold record in my bedroom, nothing would make me happier.”

THE FIRST RECORD I EVER BOUGHT: ” ‘Breakfast in America’ by Supertramp. I love that record. I’m not embarrassed to say it. It’s a good record.”

THE FIRST CONCERT I EVER WENT TO: “Van Halen, right before ‘Diver Down’ came out and they did that tour with the penguin with the hammer on the T-shirts. Do you remember that? I went with a friend of mine’s older brother at the University of Illinois at Chicago Pavilion. We had horrible seats, we were behind the stage.”

THE LAST CD I BOUGHT: “The Coldplay record, ‘Parachutes.’ It’s melody music from Britain. I love it.”

BWF (before we forget): For a steady diet of Caviar on the Web, visit www.caviarmy.com.