David Thomas, founder of legendary underground act Pere Ubu, comes from a long line of arty rock 'n' roll instigators and provocateurs like Captain Beefheart and Frank Zappa, though, as any good contrarian must, Thomas disavows the tags applied to him and his band.

David Thomas, founder of legendary underground act Pere Ubu, comes from a long line of arty rock 'n' roll instigators and provocateurs like Captain Beefheart and Frank Zappa, though, as any good contrarian must, Thomas disavows the tags applied to him and his band.

"People like to pigeonhole things into genres, and I disagree with every genre they try to label us with," Thomas said over email. "Journalists claim [Pere Ubu] is punk, post-punk, pre-punk, industrial, post-industrial, rock, prog-rock, dance … I have always tried to explain that Pere Ubu is in the mainstream. We are traditional."

Listening to Fire Records' recently released Pere Ubu box sets - Architecture of Language 1979-1982 and Elitism for the People 1975-1978 - "traditional" is not the first word that comes to mind. Since its early days in Cleveland in the mid '70s, Pere Ubu has been predictably unpredictable in its sound. Each album of absurdist, utterly compelling art-rock is distinctly different from the previous record.

"When this started it was supposed to be about recording a single 45 with the ambition that someone would one day find it in a used record store bin and they'd think it was cool. That was it," said Thomas, who joins his bandmates for an Ace of Cups concert on Sunday, July 3, which will focus on material culled from the twin box sets. "When we were recording [1978 album] Dub Housing, [former Mercury Records A&R head] Cliff Burnstein told us that if we did that album two more times we'd be huge stars. But we chose to do what we want instead, to keep pushing for more, and as such the job will never be done. Everything I've done has been a failure. I will keep working until I get it right, or die trying."

Thomas, who went by the name Crocus Behemoth when he began his music career as a founding member of proto-punk act Rocket from the Tombs, is wholly devoted to his music and has become well known for his uncompromising views on performing. Thomas isn't onstage to have a good time, nor is he there to make sure the crowd has a good time. He even finds applause distracting. The audience's only job, Thomas claims, is to stand there.

"We do the show and nothing interferes. If somebody's equipment breaks, we keep going," Thomas said. "No one has a thought or motivation other than being in the moment and in the band. … It's well known that I'm not averse to stopping a song midway if it's not going the way it should. You identify the problem, fix it and you start again. I don't pay attention to whether the audience is happy or not. If it isn't right, then it's my job to make sure it's put right - not for them, the audience, but for us, Pere Ubu. We don't consider what we do as 'fun,' and we never just go through the motions."

These days, Thomas, 63, sits in a chair while performing alongside drummer Steven Mehlman, bassist Michele Temple, synth/theremin player Robert Wheeler and Whiskey Daredevils/Rocket from the Tombs guitarist Gary Siperko. Remaining seated doesn't change the show, Thomas said. "I sit down so that every energy is put into the performance, vocally and physically," he said. "The set we are doing is brutal - one and a half hours long, and we never compromise on that performance. I sit down. Big deal."

Thomas now calls Sussex, England home, and though Pere Ubu's origin story begins in Ohio, Thomas said he doesn't pay much attention to nostalgia, nor will the band's show at Ace of Cups on Sunday be any different from other stops on the tour.

"Every show gets the same treatment. Every show is like the first or last show, although touring with the early songs, '75 to '82 - some of which we'd never played before - is unlikely to ever happen again," Thomas said. "With touring, things never really change and the routine doesn't change whether it's in the USA or Europe. You get up, drive for miles, show up, play a show and grab a few hours' sleep if you're lucky before getting up and doing it all again the next day."

There is one difference between American and European tours, though. "The U.S. has better diners," he said. "We're big fans of Cracker Barrel."