Undercover Vol. 2 (Lumenhouse, 2017)

The Infamous Stringdusters are keeping busy. Their third release of 2017, "Undercover Vol. 2," the second-half follow-up to 2015's "Vol. 1" is a five-track adventure that pays respect to a few of the band's favorite artists. From Marvin Gaye to The Cure, the 'Dusters once again push the limit of bluegrass. Long considered a progressive bluegrass band, The Infamous Stringdusters may have stumbled into something new, alternative bluegrass perhaps.

Regardless of the label, "Undercover Vol. 2" is a nostalgic glimpse into the band's influences. The acoustic instrumentation applied to The Cure's "Just Like Heaven" is fresh, giving it a modern feel. The 'Dusters show off a little bit on The Allman Brothers' classic instrumental, "Jessica." The harmony lead work alone between Dobro and banjo, by Andy Hall and Chris Pandolfi respectively, is astounding. The ascending and descending riffs alone are enough to please Allman purists and bluegrass fans alike.

Gaye's "What's Going On" is another trip to the '70s, although this time with a slightly different bluegrass-meets-Motown feel. Though perhaps not quite capturing the mournful emotion of Gaye's original (to be honest, few can), the 'Dusters' are still able to capture the essence of the classic song, whose themes are still as relevant today as they were in 1971. Fiddles, Dobros, and banjos are often happier sounding instruments by nature, making their successful implementation on a soul staple that much more impressive. The EP is rounded out with My Morning Jacket's "Golden" and Draft Punk's "Get Lucky" both very likely better than the originals.

With influences ranging from mournful soul and jam band music from the '70s to recent pop tunes reminiscent of disco, it is easy to see why The Infamous Stringdusters are so easily able to push the boundaries of what is considered acoustic or bluegrass music. Whether considered alternative or progressive, it really makes no matter, "Undercover Vol. 2" is a perfect example of what those boundaries look like when pushed to their limit.