With each passing year, Stuart Murdoch, lead singer and songwriter for Scottish indie-pop collective Belle and Sebastian, becomes a bit more deliberate in his approach.

With each passing year, Stuart Murdoch, lead singer and songwriter for Scottish indie-pop collective Belle and Sebastian, becomes a bit more deliberate in his approach.

In the band's earliest days, songs tended to arrive in a mad, churning rush - "I was surfing a ball of fire and I couldn't stop myself from writing; it was life itself," said Murdoch, 46, reached in a hotel room in Portugal for an early May phone interview. These days, however, the material tends to accumulate more gradually, like snow cover during a late-November flurry.

"Things do tend to slow down as you get older, and you're more conscious about what to try and write songs about, which is a little bit fraught because the best songs still tend to rush out of you," said Murdoch, who joins his bandmates in headlining the Next @ Wex Fest at the LC Pavilion outdoors on Sunday, June 14.

To counter this natural deceleration, Belle and Sebastian has increasingly folded more up-tempo elements into its once-insular bedroom sound, introducing shimmering disco grooves and hip-shaking club beats on the aptly titled Girls in Peacetime Want to Dance (Matador), which surfaced earlier this year.

"I think you naturally age toward dance music because it helps lubricate the proceedings when you've been playing music with the same people for so long," Murdoch said. "We've all been to those clubs, and it's hearing the music in its best way: really loud with a group of cool people freaking out on the dance floor. It makes you jealous. It kind of throws down the gauntlet to any person in a band, and you want to try and give people a similar experience."

The frontman further attributes this growing swagger to the relative simplicity of the songs he brought into recording sessions, including "Nobody's Empire" and the chirping spring garden of "Play for Today," which left ample room for the dancing basslines of new band member Dave McGowan.

"They're all very simple songs; there aren't many chord changes, and they have simple rhythmic phrases that go all the way through them," Murdoch said. "A lot of the songs are based on the kick drum, and then the bass guitar comes in and creates a lot of that rhythm, which is something quite new for us."

Of course, the Glasgow dwellers haven't entirely shed their wool cardigans, and even the most upbeat numbers - the percolating, EDM-ish "Enter Sylvia Plath," for one - incorporate heady lyrics borne of political unrest, the 9-to-5 workaday grind and the gnawing toll enacted by physical and emotional distress.

"Lying on my bed I was reading French/ With the light too bright for my senses," Murdoch sings on "Nobody's Empire," a song rooted in his early adulthood struggles with Chronic Fatigue Syndrome (a topic the musician has explored in the past, though never this explicitly). "From this hiding place life was way too much/ It was loud and rough around the edges."

While these inward treks have long been a hallmark of the band's approach, Girls in Peacetime also finds Murdoch & Co. extending a lingering gaze outward, tackling political issues on songs like "Cat With the Cream," a lush, orchestral tune that takes a jaundiced view of the "men in frocks [who] debate all the policy changes."

"As soon as you start looking around … you're going to have more of a worldly view," Murdoch said. "And it's something I thought I should do; I thought I should reflect on the world some instead of this one square mile of Glasgow I always seem to write about."

But even in those moments where the musician observes mankind at its most poisonous, a sense of optimism cuts through the proceedings like a lighthouse beacon on a foggy night - a rosy view that surfaces most cleanly on "The Everlasting Muse," where Murdoch sings, "I'll set a snare in the evening air/ Made of faith and hope and doubt."

"Whether it's music or film, I always look for that sense the artist or director is interested in the spiritual, and that immediately makes me feel better about things," said Murdoch, who has taken to practicing meditation and attending Buddhist talks in recent years, both of which, he said, serve as a complement to his Christian faith. "I would hate it if all we brought to the stage was our reservations and our fears. I couldn't do that to people. Music is a way of working out your problems and putting your best face on the world. It should be an optimistic thing."