Call it the mountain muse, the happiness of the heights or maybe it’s simply the mix of altitude with attitude. Whatever the case, Yonder Mountain String Band have captured that freewheeling spirit for the better part of 17 years—a connection that has to do with more than the imagery implied by their name alone. Notoriously independent, they blend the frenzy of bluegrass with improvisational instincts and populist sentiments, a combination that’s helped them become both festival favorites and indie entrepreneurs. Despite the departure of co-founder Jeff Austin, core members Adam Aijala (guitar, vocals), Ben Kaufmann (bass, vocals) and Dave Johnston (banjo, vocals) are pressing on Black Sheep, their first album without the mandolinist, shows little change in a sound that’s earned them a fierce following in their home state of Colorado and elsewhere.

After recruiting two new colleagues in Austin’s absence—mandolin player Jacob Jolliff and former Cornmeal fiddler Allie Kral—Yonder Mountain String Band continue to purvey their robust intents, even while ensuring that Black Sheep is more song-centric than ever before. A lively, if unlikely, take on the Buzzcocks’ “Ever Fallen in Love” shows a renewed interest in expanding their parameters, and while other songs tap the combined assets of their instrumental arsenal, the sound is as focused as it is frenzied. “Annalee” and “Landfall,” two of three tunes here that have been in their setlist for some time, offer melodic respites, but it’s the forward surge of “Around You,” “Drawing A Melody” and “Insult and an Elbow” that provide primary focus.

Amid all the revelry, the lyrics take on an added importance, with individual offerings detailing the implications of an individual’s actions, relationship realities, escapist obsessions and living the life of a modern minstrel. Like Steep Canyon Rangers, with whom they find share sound similarities on songs such as “Black Sheep” and “Around You” in particular, Yonder Mountain make music for modern ears while also tapping tradition and archetypical anecdotes. A reinterpretation of “New Dusty Miller,” an age-old fiddle tune, finds the conventional and the contemporary in a perfect mesh. Ultimately, Black Sheep is the start of the band’s second act and quickly proves that the reconfigured Yonder Mountain String Band are well poised for the future.