The fringes of the heavy metal establishment have delved to unexpected depths in the past two decades – perhaps typified by the prevalence of corpse paint in black metal, and indeed the common absence of drummers at the doom/stoner end of the spectrum. Om perhaps represent the least expected turn within the art form best known for extremes in hair length, volume and trouser armadillos, as they’ve gone right through the black of the void, and shot straight out of the other side to be bathed in white heavenly enlightenment. The concept of decapitating a metal band of its sacred guitarist and replacing it with an ominous vacuum may have once seemed sacrilegious, but having done the unexpected, Om have taken it to the most blissful possible extreme. While the new directions of last year's Advaitic Songs and the preceding God Is Good (both made minus former drummer and Sleep member, Chris Hakius, and with new members, Emil Amos of Grails and Robert Aiki Aubrey Lowe of Lichens) espoused a palette that was certainly broadening way beyond the ‘stoner-band-rhythm-section’ aesthetic upon which Om was founded, the immovable core perfected on Pilgrimage is still responsible for their live show’s dizzying peaks. That shimmering, spiritual/space rock, based around little more than a rootless bass line, and almost lifted wholesale from 'Set The Controls For The Heart Of The Sun', is a powerful fundamental upon which to base almost an entire discography, and Om's dogmatic adherence to it is perhaps what makes it quite so mesmerising.

The high ceilings of the Village Underground make it seem almost cavernous in London terms – temple-esque, even. At 9 pm we’re still queuing outside on a nippy evening, and make it inside just in time to grab a grossly overpriced 330ml can of Singaporean beer (even enlightening entertainment comes with its fair share of inescapable suffering) and take position at the back of the crowd as singer and bassist Al Cisneros, Amos and Lowe walk on to a stage bathed in blue light. Seated behind his signature synthesiser set-up, Lowe unleashes synthetic drones and the sampled Tibetan chants discernible from side B of Advaitic Songs, before the first of Amos’ many god-of-rock drum fills kicks down the doorway for the meditative groove of ‘Sinai’. Spewing pseudo-religious lyrics from the shadows, Cisneros looks to be in a state of nirvana, while Amos’ hypnotic drumming (that monotonous ride cymbal is almost a call to prayer in itself) and Lowe’s ecstatic tambourine playing (ritualistically hurling it up and down and round and round) all reach to affirm the music’s pervasive sense of drama. Despite the theatrics though, it is at first… underwhelming. The tattoo on the face of the guy to my left, and the one-upmanship of my surrounding peers – all of whom have had closed eyes and nodding heads since note one, perhaps in an attempt to appear the most ‘affected’ by the music – begin to make the thing seem somehow contrived.

Another overpriced beer, and another ten-minute meditation, and the endless cycle of the music begins to take hold. Far from contrived, that pervasive drama in Om is inescapable when consumed in its long form. Cisneros in particular has only two settings – restlessly quiet and demonically loud – and the ebb and flow between the two across a full live set emphatically hypnotises. Many songs are merely the same four bars, revised ad infinitum and paired with Cisneros’ barely audible stream of consciousness chants (words like ‘Ezekial’, ‘Lebanon’ and ‘light’ are on occasion discernible, which is enough for the aesthetic effect to be fully felt). Though Om’s music is (understandably) same-y, tracks from the last two albums are occasionally identifiable – most notably ‘Haqq al-Yaqin’, the cello line of which is now supplanted with an epic electric guitar line courtesy of Lowe – but it barely matters, and the show highlights fall within those moments when the spiritual tension reaches its almost unshakable pinnacle. The final song unfolds on a perfect loop, repeating and repeating and repeating with little variation beyond some lightly applied dub effects from Lowe onto Amos’ persistent rim shots, gradually bringing it into focus and centre stage. The flesh of the music simply melts away piece by piece, eventually leaving little more than that heartbeat of a single drum hit. His band mates’ heads already bowed, Amos continues striking for as long as possible, until one final echoing hit brings the show to a peaceful close.

Back in Sleep, Cisneros could only reach nirvana once in an hour. Now Om have tapped into the source, and sculpted an aesthetic that can grant listeners access to meditative bliss multiple times in one sitting. The adoption of Christian iconography in their artwork since Pilgrimage may have initially seemed needlessly ostentatious, yet the live show convinces me otherwise. Meditation need not be silent, and repentance needs not belief. Om’s theatrical repetitions tap into a core truth, that the world – and indeed time – are all mere distractions from inner space. Stop time and cut out all the noise of the world, and the truth will be revealed.