A couple or so months ago, I was grappling with Bonnie “Prince” Billy’s “Lie Down In The Light”, and wrote about Will Oldham’s increasing penchant for setting his voice up against more conventionally mellifluous female foils. That point seems worth making even more today, with the arrival of a new live album by the great man, “Is It The Sea”.

To be specific, this one’s precise billing is Bonnie “Prince” Billy With Harem Scarem And Alex Neilson, and the action was captured by the BBC at an Edinburgh gig in 2006, on one of those tours where Oldham seeks to rethink his back catalogue by recruiting a fresh bunch of musicians. Neilson is a fairly obvious choice, since the Scottish drummer has a pretty elevated reputation in leftfield and improv circles, and has accompanied the likes of Jandek, among others, in the past.

The really interesting development here, though, is the involvement of Harem Scarem, a Scottish folk group who, I must admit, I haven’t come across before, and who feature four female singers, also armed with fiddles, flutes, banjos and so on. It’s these four voices that provide a lavish, hand-knitted cushion for Oldham’s edges, turning “Ain’t You Wealthy? Ain’t You Wise?” into something of a tender lullaby.

As usual, I’m tempted to dust down the Dylan analogy here, and go on about Oldham’s restless treatment of his own songs. But I can’t recall Dylan ever straying quite so far as this – though of course, musicologists would doubtless point to the historical ties between Celtic and Appalachian music. The most important thing here is how well these rethinks work: “Cursed Sleep” might be a tremendous relative of Nick Drake on record, but here it’s transformed into a great brooding, bristling epic.

There’s a similarly potent version of the traditional “Molly Bawn”, arranged for the occasion by Alasdair Roberts, who’s often been compartmentalised – by me, for a start – as a kind of Scottish folk equivalent to Oldham. If there’s an obvious Scottish counterpart to a lot of this music, though, I’d lean more towards James Yorkston, thanks to the windy propulsion, the gathering majesty of much of this music, not least when Neilson rustles up a sort of breakbeat to drive “Arise Therefore” on to mighty heights.

Oldham sounds hugely energised by the whole thing, as he teases audience members making requests, and matches Harem Scarem for their vivacity and warmth. There are a few capricious discoveries: one of the best things here is something I can’t recall noticing before, a Superwolf-era b-side called “Birch Ballad”. And one mild disappointment: a fractionally misfiring version of one of my favourite Oldham songs, “New Partner” (redone better by the Nashville all-stars band on “Greatest Palace Music, if memory serves).

Nevertheless, another lovely record to add to an astonishing catalogue, and if anyone can tell me more about Harem Scarem, so impressive here, please don’t be a stranger.