Watch as the Avett Brothers tear through both 'Head Full of Doubt/Road Full of Promise' and 'The Race is On' during their Saturday (June 7) set at Mountain Jam X.

'Head Full of Doubt/Road Full of Promise,' one of the Avett Brothers' most recognizable songs, originally appeared on their Rick Rubin-produced 2009 major-label debut, 'I and Love and You.' Scott and Seth Avett lead a raucous crowd through its anthemic lyric of empowerment, while Tania Elizabeth adds a sawing violin accompaniment. The live setting only imbues this song cycle with more episodic power.

The Avett Brothers were also joined by Bob Weir for a fizzy cover of George Jones' 'The Race Is On,' recalling the Grateful Dead's take from 1981's 'Reckoning' -- but with flashes of free-wheeling, North Carolina-inspired bluegrass thrown in.

The Avett Brothers are rounded out by Bob Crawford, Joe Kwon, Mike Marsh and Paul Defiglia. The group is in the early stages of a new studio effort, again to be produced by Rubin. Last year's 'Magpie and the Dandelion' went to No. 5.

Watch the Avett Brothers Perform 'The Race is On' With Bob Weir

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