Derek Trucks, the wunderkind of the Allman Brothers Band and the youngest musician to make it onto Rolling Stone's “100 Greatest Guitarists of All Time” list, has his own sprawling rock clan, a motley assortment of down-South childhood friends, a Phish-by-way-of-Africa drummer and others drawn to the fire of never-ending jam sessions. Proving that Southern and worldly aren't incompatible adjectives, The Derek Trucks Band improvises on a global scale. Classical Indian, Motown, African, Southern rock and blues are all there, fitting into gritty, foot-bouncing songs. The talented and relaxed band released its sixth studio album, “Already Free,” in January, and its tracks prove that Trucks can strum a sarod as masterfully as he can demolish an electric slide guitar. Before taking its tour to Japan, the band performs The National Friday, Aug. 14, at 8 p.m. $20-$35. 612-1900. — Laura Robertson