As the rhythm section of legendary early '90s San Jose doom-metal trio Sleep, bassist Al Cisneros and drummer Chris Haikus could easily have recruited a new Tony Iommi disciple and continued to work the Black Sabbath template they'd perfected with guitarist Matt Pike. But much as Pike decided to explore different territory with the galloping metal onslaught of his successful band High on Fire, the two musicians who make up Om have followed their muse to an unexpected intersection of transcendent psychedelia and heavy rock.

Exploring extended themes with their slow-building, minimalist tunes that eventually explode into distorted bass riffs and thunderous drums, Om have forged a unique sound since the duo reconvened in 2002 (Cisneros took an extended break from music after Sleep split up). Have put out two critically acclaimed albums on locally based imprint Holy Mountain, Om made the move to indie metal label Southern Lord for the 2007 release of the band's stellar effort Pilgrimage.

While echoing on the over-driven bass drone and vocal incantations that marked earlier recordings, Pilgrimage further developed the band's songwriting and elevates the mesmerizing power of their subtle, psychedelic mantras. The departure of Haikus from the band cast the future of Om in doubt, Cisneros found an able collaborator in Grails drummer Emil Amos. The duo's first recorded output -- God is Good for Drag City Records -- introduced somewhat shorter song structures, cello and the droning Indian tamboura to the mix with stunning results.

For the group's latest effort, Om has brought on multi-instrumentalist collaborator Robert Lowe (of the solo psych project Lichens) and further expanded its sonic palette to include more strings and sampled chants on last year's transcendant Advaitic Songs. Om performs at the Independent with support act and Sun City Girls founder Sir Richard Bishop delivering a solo guitar set.

Om with Sir Richard Bishop
Wednesday, Feb. 20, 8 p.m. $15
The Independent