New Extreme Metal Festival to Debut in Denver

Denver metalheads, rejoice! There’s a new homegrown extreme music festival coming to town this summer, courtesy of longtime local producer Dave Otero.

The owner and operator of Flatline Audio announced full details on Thursday, January 8, for the inaugural Flatline Fest, which will bring a stacked lineup to the Oriental Theater for two days this summer.

Denver Flatline Fest Lineup, Tickets and Dates

The weekend kicks off Saturday, June 13, with Canadian tech-death titans Archspire, Belgian brutal-death machine Aborted and Nashville technical melodeath merchants Inferi, alongside Colorado acts Nuclear Power Trio, Of Feather and Bone, and Clusterfux. The second day, Sunday, June 14, features California deathgrinders Cattle Decapitation, LA tech-death crew the Zenith Passage and Denver death-metal legends Cephalic Carnage, as well as native heavy-hitters Allegaeon, In the Company of Serpents and Necropanther.

Yeah, absolutely stacked. Two-day passes are $90; single-day tickets are $50. There are also a limited number of early bird passes available for $85. All are available online now. Pricing does not include ticketing platform fees.

With such a diverse lineup, the connective tissue between all of these bands is Otero.

“I’ve collaborated with every band in this lineup in the studio over many years and have always wanted to put something like this together,” he says. “The fest is a chance to celebrate those friendships in one of our favorite independent venues.”

Highlighting the healthy and thriving home state scene, which Otero’s been involved in since he was a teenager playing in punk bands, was also part of the plan and indicative of his enduring relationships with performers such as Clusterfux, the 1990s Denver crossover group that recently reactivated.

“They were one of the bands that I decided I’d like to include way early on just to tie it back as early as I could,” Otero says, adding that brothers Josh and Justin Lent were there for some of his first shows. “Those dudes I’ve known longer than anyone else, honestly. They’ve had a resurgence, then they do Chain Reaction, which is so awesome. They’re still around, and I was around from so long ago, it goes way deep.”

Then there’s Nuclear Power Trio, the satirical three-piece that gained a viral following in 2020 for bringing together some of the most powerful and divisive political figures on the planet in the name of metal. No one knew Donald Trump, Vladimir Putin and Kim Jung Un could shred so hard, and Flatline Fest will be the masked Metal Blade project’s live debut.

“The most insane people, musicians and music. Sounds like nothing else. It’s got a lot going for it,” Otero says. “It’s crazy, I sit here and stare at the lineup and I’m like, ‘This is fucking wild.’ Every single one of these bands, I have all these memories and whole experiences tied to.”

Like Cattle Decapitation, a group Otero’s worked with on four records now, and as a result, have spent a lot of time in Denver.

“That whole band has essentially lived with me for an entire year, if you put it all together, which means they’re practically Colorado residents,” he says, adding that Flatline Studio serves as a home away from home to a lot of artists who come through. “I feel like some of these bands have slightly outsized Colorado followings because of that. People know the connection and bands are here for two months and we’re going out to shows. The Denver scene has a reputation for just showing up. For bands, they fucking love it.”

The idea of Flatline Fest was teased on social media a couple of weeks ago and quickly lit up the online metalsphere, as popular websites such as Metal Injection helped spread the word. The initial excitement and reception caught Otero off guard.

“The response to that blew me away. It was more than I anticipated, so that was surprising, but super cool and gratifying,” he shares. “It felt like the time and effort I’ve put into music over the last 25 years actually does mean something, which makes me feel all warm and fuzzy inside.”

Otero is navigating the first foray into the festival game with his fiancé and current co-promoter, Chelsea Lowe. The couple actually got engaged on-stage during an Aborted set at Brutal Assault in 2024. Now they’re ready to tie the knot the same weekend as Flatline Fest.  

“The catalyst for doing the fest at this point, even though it’s been in the back of my head for years, is how do we get all of our best friends out for our wedding to celebrate with us? No better way to ensure they’re available and they won’t be on tour than to pay them to be here,” Otero says with a laugh.  

He hints at future plans, but this first year is going to prove to be a big one for many reasons.

“It’d be silly to not keep it going,” Otero concludes. “It’s been so rewarding, why would I not do this again in the future?”