Guitarist and vocalist Warren Haynes is a busy man, juggling roles in the Allman Brothers, the Dead, and Gov't Mule, which he leads, having founded it with the late Allmans bassist Allen Woody. Like the other bands Haynes is involved with, Gov't Mule is based on a classic-rock sound: hard, blues-drenched rock with a heavy bottom, epic scope, and blazing guitar work. But it's hardly one-dimensional, incorporating slivers of reggae, jazzy improvisation, and R&B, while Haynes's vocals edge increasingly soulward.
Now a quartet including longtime drummer Matt Abts, keyboardist Danny Louis, and new bassist Jorgen Carlsson, Mule arrives at the zoo just before the release of its first studio disc in three years, By a Thread, mostly recorded at Willie Nelson's Pedernales Studio. It kicks off with a scorching guest shot from ZZ Top guitarist Billy Gibbons on "Broke Down on the Brazos." "Frozen Fear" is a hard, reggae-tinged ballad with a touch of Memphis soul in Haynes's vocals and a hint of Duane Allman in his guitar solo. And the tragic tale "Railroad Boy" is grounded in Delta blues, with a dose of Skynyrd. It's all hard-driving, blues-informed stuff played with sweaty intensity and designed for braying at the moon.