For a couple of stoners, the members of Om have a lot of focus. The San Francisco bass-and-drum duo’s attention barely wavers from its tried-and-true template of low frequencies, cyclical melodies, and arcane chants. Pilgrimage, the band’s most recent record, approximates what would happen if Black Sabbath bassist Geezer Butler disappeared into the Egyptian desert to cloister himself in an open tomb where he might sit beyond the reach of sunlight and contemplate the unknowable power of the gods before returning to civilization on a mission to preach his mysterious wisdom via round-wound strings and Sun amplifiers. In other words, it’s pretty heavy. And when—like Om—you are capable of being that heavy, it’s probably hard to concentrate on anything else. Om performs with Grails and Jack Rose at 8:30 p.m. at the Rock and Roll Hotel, 1353 H St. NE. $12. (202) 388-7625.