It’s been over a decade since Kendrick Lamar welcomed a cabal of Los Angeles’ most brilliant jazz beatniks into the studio to forge a body of songs that would affix the words “voice of a generation” to his name. The sessions were a catalyst from which a collection of cosmically aligned instrumentalists that included Kamasi Washington , Terrace Martin , and Thundercat released a rush of envelope-pushing jazz fusion music that both inspired and took inspiration from the Black Lives Matter movement. It was a righteous explosion of Black artistic and sociopolitical expression that firmly established L.A. as the most happening center of the jazz universe. Coming up in the scene were brothers Aaron and Lawrence Shaw, young working musicians with Garveyite roots—their most visible credit was probably Aaron’s assist on Tyler, the Creator ’s vibey yet structurally complex 2015 song “ 2Seater .” The pair’s Black Nile project began to take shape as the decade came to a close.…