The second word of Boulder Acoustic Society’s bio is “moody.”

With good reason. It’s those five letters that set this band — an, um, acoustic group from Boulder, Colo., if you’re wondering — apart from many of its contemporaries on the string-band scene.

See, when I hear that a string band from Boulder is coming to Bend to play McMenamins Old St. Francis School, certain images rush into my mind: happy-go-lucky jamming, ponytails bobbing to a breakneck rhythm, crooked grins partially obscured by a week-old beard. In Boulder, life-is-good jam-bands are a dime a dozen.

But the Boulder Acoustic Society is different. These four dudes do use acoustic instruments (fiddles, ukes, etc.), but the music they make is more inclusive, more eclectic, more reflective than you might expect. The band’s tunes are a mashup of Americana, pop and indie-rock, with a decidedly dark, despondent streak.

BAS arrives in Bend having just released its new album, “Champion of Disaster,” earlier this week. Visit www.boulderacousticsociety.net to get a taste of their brooding brew.

Boulder Acoustic Society ; 7 p.m. Wednesday; free; McMenamins Old St. Francis School, 700 N.W. Bond St., Bend; 541-382-5174 or www.mcmenamins.com.