San Diego's The Black Heart Procession has been making somber, lovelorn sounds since 1997. While the music may dwell in the indie rock style, it's informed by murder ballads, the blues and other forms of early Americana. The group uses an ensemble of instruments—most notably the saw—that result in a velvety, gloom-imbued aural texture. See The Black Heart Procession live on Tuesday at Low Spirits at 9 p.m. Admission is $12.