D.C. rapper LB199X. (Photo by Tyler Austin)

Meet LB199X. His rap alias sounds as mysterious as your neighbor’s WiFi network name, but his music feels generous and forthright — especially on “Black Matter,” a new album of diaristic meditations on life in the Black Lives Matter era. The rapper’s most lucid refrain — “Black matter, you matter, I matter, we matter” — provides the album with its fulcrum and its climax, radiating affirmation in every direction.

“ ‘Black Matter’ is about everything,” LB says. “It’s about me, my thoughts, where I come from, who I am, why I am and what I am.” That might sound a touch self-interested coming from a hip-hop altruist, but LB knows that rapping for others and rapping for himself are really one and the same. “With my music, as much I want people to hear it, I need to hear it,” he says.

Born and raised in Southeast Washington, LB moved to Orlando after high school, where he says he began taking his rhyme-craft more seriously — and in every sense of the word. Now he’s back in the District, rapping explicitly about patience, gratitude and self-awareness with clear eyes and a deliberate step.

And although his nom de rap still carries some mystique, he’s happy to wave it away. “LB comes from Lil’ Black,” he says, explaining that his father used to go by the nickname “Black.” As for the 199X, “it stands for anybody born between 1990 and 1999.”

Fittingly, the stage name exists parallel to the music. “It’s for me,” he says, “and it’s for the people.”

Show: Opening for Not Your Groupies and NanaBCool on Oct. 27 at 9 p.m. at DC9. $10.