For the best window into the New Albany, Ind. band Houndmouth’s raucous, ragged rock ‘n’ roll side, go straight to track three on their newest album, Little Neon Limelight. It’s an ecstatic, primal scream of a song called “15 Years,” with jagged-edge guitars and a barely contained rhythm section bashing away underneath a choir of vocal harmonies. By any standard, it’s a great rock song, but it’s not the only thing the band does well. The first two songs on the album, “Sedona” and “Otis,” take a cooler, more blissful approach, specializing in sweetly infectious hooks and wide-screen sound that calls to mind some of the more mellow work of My Morning Jacket. Add in the soulful, sensual vocals of keyboard player Katie Toupin, and this is one addictive record.

Toupin’s vocals are vital to many of the songs on Little Neon Limelight, either as the centerpiece or as part of the backdrop, and it’s difficult to imagine the album without her. But that’s exactly what’s going to happen, because Toupin left Houndmouth at the beginning of April (a press release described the departure as “amicable”), just as their latest tour was about to begin. It was an abrupt departure at the worst possible time.

Since forming in 2011, the group’s forward momentum began almost immediately. They played a SXSW show to promote their homemade EP in 2012, catching the attention of Geoff Travis, the head of Rough Trade Records. They signed with Rough Trade, were named Band of the Week by The Guardian, released their debut album, From the Hills Below the City in 2013, made the talk-show rounds with appearances on the Late Show with David Letterman and Conan and played Bonnaroo and Lollapalooza. After all that time and attention, it’s got to be a little difficult to adjust to losing a key member of the band, right? Well, after a few initially scary moments, it actually seems to have gone just fine.

“It was definitely nerve-racking at first,” says Houndmouth drummer and vocalist, Shane Cody. “But we’ve added two guys on tenor and baritone sax and a keyboard player out of Nashville, and the band’s got a completely different vibe now. We’ve really gotten into it.”

In fact, the new players in question — keyboardist Caleb Hickman and horn players Graeme Gardiner and Drew Miller — were so skilled that they were able to come up with their own parts for the band’s songs with minimum rehearsal. And “minimum” in this case means that the new lineup only had time for two rehearsals before the tour started.

“These guys are so talented, and they’ve been able to add so much,” Cody says. “And we’re only about a week in, but it’s been really great and we’ve been getting a really good audience reaction.”

Of course, adjustments had to be made to a lot of the songs. “I’m singing more than I was and [bassist] Zak Appleby and [guitarist] Matt Myers are, too. But it’s really cool to see it evolve, and the songs have a lot more energy. We’ve just been having a blast so far.”

Cody adds that now that everyone onstage clearly wants to be there, the general attitude in the band has changed as well. “It’s sad to see someone leave, but it’s really become a positive thing,” he says. “Everyone’s happy, and that’s going to translate onstage.”

The band was already familiar with their three new touring musicians before recruiting them — they’d all passed the vital “Can We All Get Along in the Van?” personality test. “That’s probably the more important thing, in my opinion,” Cody says. “Because you’re together all the time. We got good vibes from them, and they’re all good guys and super talented. So we kind of lucked out that all three of them could jump on so quickly. It already feels like we’ve been playing together for a while.”

In fact, Cody says that the band has had an ever-evolving vision of what their sound is, and for now they’re enjoying what the new version of Houndmouth has morphed into. “We’ve always just kind of felt things out and done what we felt comfortable doing. But these first few shows have really been a game-changer,” he says. “We’ve always worked on defining who we are, and we’ve been lumped into the Americana-folk thing, and we always just thought that we were a rock band.”