The words “experimental,” “underground,” and “DIY” get thrown around a lot these days, but Alvarius B. has existed in those worlds — and helped define them — since forming the trio Sun City Girls in the early Eighties. Emerging from Arizona’s hardcore scene, Alvarius B. (then known as Alan Bishop), his brother Richard Bishop, and Charles Gocher created a style that hinged on being unpredictable and independent-minded. In hundreds of recordings and live shows, the band improvised a blend of noise, free jazz, world music, and more. When Gocher died in 2007, Sun City Girls broke up, but Alvarius B. has carried on their legacy with his solo work. Catch him in a rare Bay Area appearance at a Stranded Records-hosted show at White Horse Bar (551 Telegraph Ave., Oakland) with Climax Golden Twins founder Robert Millis, another master of free-form music.