“We stayed at Hicksville Trailer Palace, which is basically a bunch of vintage trailers around this recording studio,” singer Bret Constantino said. “There’s activities, a pool with underwater speakers and a great jukebox, fire pit and a Jacuzzi on top of a tower. It was a great creative outlet in that sun. It worked its way into the record, even if I can’t tell you exactly how.”

Oddly enough, the result, Spine Hits, may be Sleepy Sun’s least trippy effort to date, with tracks falling more in line with diet-psychedelic grooves of My Morning Jacket or Lou Reed.

“We tried to write songs for this record,” Constantino said. “It became more about conveying an idea or feeling within a shorter time span. That was a conscious effort to write songs as opposed to finding songs out of jams. Lyrically even, there’s a conciseness we didn’t have before.”

The San Francisco-based Sleepy Sun’s prior well-received efforts (Fever and Embrace) garnered it spots opening for Arctic Monkeys and The Black Angels, and soon, the band found itself spend ing every minute on the road. That grueling schedule and creative differences led to the departure of vocalist Rachel Fannan, who lent a feminine touch to the otherwise macho stoner tracks.

Spine Hits — which hit shelves last week — is the first album without Fannan, but Constantino and company embraced the situation with open arms.

“It didn’t change much in terms of how we work together, but also, we did leave space for her before,” he said. “Knowing that there wasn’t going to be a female voice — musically, there’s not the same dynamic, but we kind of wanted to prove to ourselves that the band is about these members, the ones who have given up everything to be a part of it.”

Summer festivals and European dates will follow Sleepy Sun’s current tour, which stops Sunday at The Conservatory, and Constantino is enthralled with what the future holds.

“It’s pretty wild what we do,” he said.

“This is pretty fucking cool that we are still doing it. I’m excited to share what we made. It’s a beautiful thing for me.”