The third album by Om, a duo from San Francisco, took some pretty circuitous route to get to Uncut, or so it seemed: at least two copies of “Pilgrimage” disappeared en route, as I became more and more anxious to hear it.

As it turned out, I might as well have brought in my copy of their last album, “Conference Of The Birds”, and duped myself into believing it was the new one. Some bands progress, some change radically, but others – The Ramones, say – set their aesthetic parameters very early on, then ruthlessly adhere to them for the rest of their lives.

This, I guess, is what Om do, and it works for me. For those of you who haven’t experienced them – and listening to Om is quite a physical experience, if you turn the bass up as it should be – they’re a duo consisting of Al Cisneros (vocals and bass) and Chris Hakius (drums). On the sleeve of my promo of “Pilgrimage”, it describes the record as “Three songs featuring Om’s unique use of riff, cadence and chant.” Which is pretty good, but I’d also go for “Gregorian Metal”, or maybe “How ‘Set The Controls For The Heart Of The Sun’ would sound if it was played by Geezer Butler and Bill Ward.”

They’re a pretty remarkable band, actually, very much forefathers of a certain hipster doom strand of metal thanks to their earlier career as two-thirds of Sleep, whose legendary “Dopesmoker” track lasted about an hour, if memory serves, and set the template for any number of dirge-paced, cosmically-inclined psych metallers.

It’d be easy to portray Om, consequently, as the natural end product of stoner rock, and that’s fine. But what makes Om even more interesting is how they use the dynamics of heavy rock – slowed to a monolithic trudge – and extremely deep bass frequencies to create a kind of transcendental state. This is immensely high-minded music: “Lyrical themes,” continue the sleevenotes, “address the processes of mind, psychic reality, astral and casual planes of being and the nature of the soul.”

In a certain mood, the devotional sludge that results from these ambitions – the stand-out track here is called “Unitive Knowledge Of The Godhead”, snappily – can seem pretty daft. But there’s something profoundly hypnotic about Cisneros’ incantatory mutter, to the armour-plated drones that these two monastic rhythm masters conjure up. It’s 9.50am, and I’m not quite levitating yet, but “Pilgrimage” is the audio equivalent of a long deep shower at the start of the day: flush out those toxins with a refreshing metal dirge, I guess. Works for me.