"Martin Hayes is the most difficult performer in Ireland to write about because what he does is beyond words on account of it's being beyond comprehension."

It's not often you find Eamonn McCann lost for words but his recent lines on the force of nature that is the fiddle player from Clare carry the authentic ring of astonished truth. As the final notes of Live In Seattle, the latest outing from the duo of Hayes and guitarist Dennis Cahill, sink slowly beneath the horizon, it feels less like the end of a cd than the breaking of a spell cast by music of supernatural origin. You don't just stop listening, you have to disengage – and, suddenly, you find yourself closer to an understanding of why the fiddle is the favoured instrument of entrapment and entrancement in Irish folklore.

Then again, Hayes and Cahill have a distinct advantage over the fabled little people in so far as (a) our heroes do actually exist (well, I've seen them anyway, I swear) and (b) they bring to an already vibrant interpretation of the ancient rites an openness to jazz, rock 'n' roll and even classical influences that, as Bill Graham once neatly observed, allows them the feat of communicating in the present without sacrificing the past. In his sleevenotes Hayes himself talks of the contrasts in the music in terms of "things that are sometimes more clearly understood by direct experience of their opposite" and of the similar, mutually inclusive relationship between tradition and innovation – but again, it's the music itself which speaks louder than any words, its free-ranging spirit at once as ancient and as up to date as the fishing net and the internet, the result a millenniel soundtrack worthy of the name.

So much for wooly abstraction; in its commitment to what Hayes calls "the spirit of the moment", Live In Seattle is also, and much more immediately, a tour de force concert performance that fires the head, the heart and the feet. The centrepiece is a breathtaking 27-minute-long suite, beginning with the wild, haunted solemnity of the Blasket slow air 'Port na bPucai' and ending in an exhilarating firestorm sparked by the fusion of trad and classical they call 'P. Joe's Pecurious Pachelbel Special'. En route, they pull out all the stops while somehow never confusing flash with substance: here are points of gossamer delicacy offset by passages of wild intensity; here are skipping violin and full-blooded guitar matching each other step for step in a dizzying dance; and, hey, is it just me, or does the bridge between the lovely lilting strains of 'Ship In Full Sail' and 'Jer The Rigger' remind anyone else of The Doors' ‘The End’? But then, I'm also a guy who thinks that, as well as everything else, this is music that is often more sensual and downright sexy than a busload of Barry Whites.

Fans of Hayes and Cahill won't be surprised by such unlikely connections. You will almost certainly find 'Live In Seattle' filed under 'Trad', or even, de lawd between us and all harm, 'Celtic', but the names Hayes and Cahill are the only guide to content and quality you really need. The raw material may be familiar but the alchemy they perform with it means they surely deserve now consideration as true Irish originals on the level of Planxty or Van or U2.

Having had the good fortune to see Hayes and Cahill in concert more than once, my only gripes are that a double-helping would have been closer to the mark and I also miss the dry wit and repartee that has the crowds rolling in the aisles when they aren't hollering or gasping or simply pinching themselves.

Otherwise, Live In Seattle is guaranteed to leave you pretty much as it arrives: speechless.