The juxtaposition is hard to miss on Mariachi El Bronx III, a record as authentically festive as Cinco de Mayo in El Sereno and seemingly beating with a heavy, telltale heart.

Singer Matt Caughthran admits he had doubts about his lyrical direction on the third full-length from Mariachi El Bronx, the Mexican-flavoured alter ego of ace L.A. punk-rock mainstays the Bronx. Those doubts were strong enough that he ended up asking his bandmates if he needed to lighten things up.

When you’ve spent the past half-dozen years playing modern mariachi music while partying in the finest black velvet double metalico suits money can buy, the last thing you want to do is get fans thinking the fiesta might officially be over.

“We had a big conversation about ‘Is the record too dark?’ and ‘Do I need to go back and rewrite stuff?’ ” the outgoing Caughthran says, reached at home in Los Angeles, where he’s writing songs for the next Bronx record. “But the consensus between everyone was ‘No—this is what it is and what it’s supposed to be. And this is what will separate it from other stuff that we’ve done—the dark tone of it.’ ”

Caughthran has no trouble discussing the lyrical inspiration for tracks like the loping kickoff number, “New Beat”, which starts with “Tonight we celebrate the sadness/Tonight we dwell in our misery/I’m giving in to all the things that haunt me/Surrendering to things that I should not be.”

“I was kind of in a weird place going into the record,” he reveals. “I was in kind of a bad place mentally, and I wasn’t certain what I was going to say and how it was going to come across—what the mission was. With writing and recording punk stuff, I’ve always taken a personal approach, and you get attached to that.”

He elaborates: “There were certain things that I’d thought I’d written out of my system, my dad dying being one of them. I had another friend’s parents die, and that kind of brought a lot of that shit back. I also had a bad self-inventory—I was kind of being a cocksucker to people. It was a tough time, and a time that I thought that I had moved past. I didn’t want to write about that stuff, but I couldn’t write about anything else because I couldn’t escape it.”

Along with his bandmates, including guitarist and main collaborator Joby J. Ford, Caughthran also set out to refocus Mariachi El Bronx. The project started as a way to do something more creatively fulfilling than hardcore punk, which is in no way a knock against the Bronx’s epic back catalogue. Going into Mariachi El Bronx III, however, the group started to feel like it had painted itself into some sort of straight-outta-Tijuana corner.

Those who love the first Mariachi El Bronx records will be happy to hear that tracks like “Eternal” and “Wildfires” once again burst with crystal-frontier trumpet flourishes and dusty-border-town guitars. This time out, though, the band aims for something more than pleasing the ghost of Antonio Aguilar. Witness how “Nothing’s Changed” comes draped in ’20s-vintage strings, while “Raise the Dead” is laced with waves of sparkling synths.

“We try to push for something experimental with every record we do just so we don’t find ourselves creatively miserable,” Caughthran notes. “It doesn’t always make sense, and it’s not always something that works, but it’s important that we don’t end up finding ourselves miserable. It keeps us sane and creatively stoked.”

Mariachi El Bronx plays the Tantalus Stage at the Squamish Valley Music Festival next Friday (August 7).