If you’ve never believed that pure joy can be expressed through instrumental music, specifically jazz music, then you might need to take a listen to the collaboration between pianist Henry Butler and trumpeter/bandleader Steven Bernstein. Their band, Butler Bernstein & The Hot 9, pits a six-piece horn section against Butler’s playful, virtuosic playing — and comes up a winner every time. In the video for one of their first recordings, a song called “Viper’s Drag,” Bernstein and the band seem caught between being professional musicians and delighted fans, watching Butler play dazzling boogie-woogie style piano, banging out a propulsive rhythm with his left hand and conjuring lightning-flash solos with his right.

The collaboration between Bernstein, a New Yorker who’s best known for his iconoclastic work with the Lounge Lizards and Sex Mob, and Butler, a 67-year-old blind-since-infancy piano prodigy who lived in New Orleans most of his life, began in the late 1990s. Bernstein served as the musical director for the Kansas City All Stars, a group of players that formed in the wake of Robert Altman’s jazz-heavy film Kansas City. But they didn’t meet again until 2012, when event producer Jay Weissman brought the two back together for a concert project he was working on with Bernstein.

“We were putting together a blues set, and I had this idea where I was going to play blues from 1890 to 1925,” Bernstein says. “Just enough to get to Count Basie. And Jay asked if Henry Butler could be a guest. I said ‘Hell yeah! Are you going to fly him in from New Orleans?’ And he told me that Henry was actually living in Brooklyn. He’d been there for a couple of years after he lost his home to Hurricane Katrina.”

The concert was such a success that the two men wanted to collaborate further, and thus the very old-school path to making their joint album, Viper’s Drag, began.

“I went to Henry’s house with my tape recorder from Radio Shack,” Bernstein says. “I like those because you can see how much time is left on the tapes. And he played me these songs and I just started taping.”

The songs were heavy on improvisation, and Bernstein transcribed and arranged them, preparing his band for when Butler came in to record with them. Butler then had the rare opportunity to improvise over the top of his original improvisations, which were now being played on other instruments.

“He had to figure out something else to play,” Bernstein says, “which really pushed him to some other stuff. We have a lot of trust in each other; I could tell when Henry was about to really explode and go off on a tangent, so I could just cut the band off and let him do this thing. I couldn’t do it with visual cues, so I had to do it with transcendental cues.”

One of the most exciting things about the Hot 9’s arrangements of Butler’s songs is that they almost seem inverted. Rather than the horn section playing over top of Butler’s piano, his playing becomes the center of the song and the rest of the band supports him.

“If you look at the history of jazz music there haven’t really been many bands with a virtuoso piano player and six horns who are not jamming,” Bernstein says. “Everything’s arranged. But it’s not a big band. The closest I think is Thelonious Monk at Town Hall, or maybe Earl Hines. That’s all you can compare it to. Most times when you get horns and piano, the piano’s in the back; with this group the piano’s in front.”

But the album wasn’t quite done yet. Butler made one suggestion: That they play the songs again with a New Orleans rhythm section, which ended up being bassist Reginald Veal and drummer Herlin Riley. It was a suggestion that Bernstein initially didn’t agree with, because he’d been working with the Hot 9’s rhythm section for years.

“We have history,” he says. “We’ve been doing this a long time. So when he suggested we should do this with a New Orleans rhythm section, I was like, ‘What? I’ve got my New York cats here! They’ve been a rhythm section for 15 years! Then Herlin and Reggie started playing and I realized, ‘Oh, that’s what he was saying.’ Once you add that New Orleans rhythm, man, that’s the real stuff. And that gave us the archetype for the songs.”

And despite having been a professional musician since he was 13 years old, and playing with everyone from Lou Reed to Aretha Franklin, the now-55-year-old Bernstein says that there are still nights when he turns into an awestruck fan watching Butler play. “The whole band does it!” he says with a laugh. “We’ve had this band for five years and we’re still sometimes just standing there slack-jawed, like, ‘What did he just play?’ His playing sounds like the oldest music you’ve ever heard and the newest music you’ve never heard. There’s so much mystery because he’s going so many places.”