During his days with stoner-metal pioneers Sleep, Al Cisneros was notorious for writing tunes that reached well beyond the usual verse-chorus-quiet-loud template. The title track of 2003’s Dopesmoker, for instance, went on (and on) for a hefty 63 minutes. Cisneros doesn’t extend himself quite so far in Om; the longest number on his newer band’s latest, Advaitic Songs, clocks in at a relatively compact 11 minutes and 24 seconds.

When it comes to words, however, the New Mexico–based bassist and singer is as parsimonious as he is sonically profligate. In fact, he’s as mysterious a presence on the phone as he is on-stage, managing to be both cryptic and concise during a brief chat with the Straight.

Yet there’s a lot to talk about with this unit. Rising from the ashes of Sleep, Om began as a bare-bones bass-and-drums unit, but on Advaitic Songs its sound has become almost lush, with liturgical chanting and ethereal keyboards wafting over Cisneros and drummer Emil Amos’s dub-influenced pulse. Then there’s the ritual aspect: Om’s compositions evoke an air of religious solemnity, and many of them have titles that suggest some connection to the Middle Eastern homeland of the Jewish, Christian, and Islamic faiths.

One of the few times in our conversation Cisneros becomes almost animated is when he recalls visiting Jerusalem in 2007. “There’s this palpable energy in the atoms,” he says on the line from his desert home. “It’s really intense and emotional there.”

But when we try to probe deeper into the spiritual basis for Om’s darkly meditative approach, he’s enigmatic. “It’s devotional music, but with the heart,” he says. “It’s not specific to one tradition. However, it’s inspired by the various traditions, the inner core of them—the contemplative, philosophical, sometimes mystical core, as opposed to ritual, ceremony, dogma.”

Fortunately, Amos, who joins Cisneros and multi-instrumentalist Robert Lowe in the three-piece, is more forthcoming.

“We get a little bit hung up in interviews, because people always ask us in what way the music is spiritual, and our response is always ‘The spiritual is not separate from your basic daily life,’ ” he says in a separate interview from Brooklyn, shedding light on both his band’s methodology and his bandmate’s reluctance to talk. “So everything going on in the music, in every way, is a reflection of the spiritual universe that we live in.

“It always strikes us as strange as people inadvertently compartmentalize it as spiritual music, because, really, Britney Spears, or anything—Foreigner!—reflects a spiritual value system and a spiritual outlook,” he continues. “It’s just that those people didn’t realize that they were basically preaching something that comes from a world-view. They thought they were just, you know, turning out Friday-night entertainment, but that’s the church that they live in. That capitalist world, that’s what they are preaching. So when people come to us and talk to us about spirituality in our music, it always seems vaguely humorous, because everything you do expresses your politics.”

In that light, Om seems a more contemplative expression of the rebellious spirit that first made its punk- and metal-rooted members want to make music. How all this will play out on-stage remains to be seen, although it’s reasonable to expect a heavier and less filigreed version of the often quite subtle sounds that can be heard on Advaitic Songs.

If this is the case, though, Cisneros isn’t letting on.

“Just go to the show!” he says, and that’s not a bad idea at all.