Great Lake Swimmers have made music in many unusual places, including a decommissioned subway station, an abandoned grain silo, and an ersatz castle on the shores of the St. Lawrence Seaway. But for the new release, A Forest of Arms, leader Tony Dekker went deeper into location recording than ever before, and we mean that literally.

On the line from a tour stop in Nelson, B.C., the thoughtful musician reveals that many of his vocal and guitar tracks were recorded in the Tyendinaga Caves, a series of limestone caverns near Belleville, Ontario.

“First of all, it had to do with the acoustics—with adding this kind of intangible sonic layer to the music,” Dekker says. “But for me, it’s also about tapping into a place and sort of documenting it. We’ve been doing location recordings over the entire course of the band: this is our sixth album, and they’ve all been recorded in different locations. Over time, I think that’s been important to the progress of the band—and I think it draws a certain kind of emotional performance out of the people that play in those scenarios, too.”

Dekker’s subterranean recording sessions might have added to A Forest of Arms’ rather ruminative quality: when the Straight suggests that the caves offered a physical analogy for his subconscious mind, Dekker doesn’t disagree.

“To be honest, I thought about that a lot,” he says. “Like, on a subconscious level, what was going on in choosing that location? On a basic level there must be something to that, for sure. A kind of mining: soul mining.”

Going deep, both physically and metaphorically, came naturally when Dekker was readying A Forest of Arms’ dozen songs. It doesn’t take forensic training to determine that the opening track, “Something Like a Storm”, is referring to the tempest a baby can bring to a household, and the singer confirms that he and his wife became first-time parents late in 2014.

But there are other fresh energies at work. With new drummer Joshua Van Tassel joining guitarist Erik Arnesen, bassist Bret Higgins, and violinist Miranda Mulholland in the Swimmers, Dekker says his band is enjoying a renewed sense of purpose.

That’s especially audible on the art-pop masterpiece “One More Charge at the Red Cape”, but it also drives “The Great Bear”, Dekker’s paean to the West Coast wilderness.

“It was inspired by a trip that I took up into the rainforest with the World Wildlife Fund a couple of years ago,” the songwriter explains. “I actually sailed on a little research boat from Kitimat down to Bella Bella, all through the islands there, and ultimately, I think that experience became the bedrock for the album. Environmental concerns have always been a part of the band, and after that trip I really felt a sense of urgency about describing the beauty of that place—and protecting it.”

Dekker went underground to bring that message to light, but if it leads to mainstream exposure he won’t mind at all.

Great Lake Swimmers play the Vogue Theatre on Thursday (June 4).