In the absence of new studio material from Tom G Warrior, this is a pleasant surprise - a recording of Triptykon's triumphant appearance at the Roadburn festival from last year. And rather than the usual selection of album cuts, the band played a special set with the Dutch Metropole Orkest providing a perfectly-judged orchestral backing, consisting of the career-long Requiem trilogy, including for the first time part 2, the newly-written Grave Eternal. That, together with Rex Irae (originally on Celtic Frost's 1987 album Into The Pandemonium, and Winter (originally from 2006's Monotheist) form a single long piece that will undoubtedly be more of interest to fans of Celtic Frost's more airy, experimental moments rather than Triptykon's heaviness.

Yet it is excellent, atmospheric and grand as an orchestra-backed band should be, yet wholly dominated by the metal instruments to the point where it turns out to become one of the more restrained symphonic performances you'll have heard. The band (consisting of Tom G together with usual conspirators V Santura (Dark Fortress) and Vanja Šlajh together with new-ish drummer Hannes Grossmann (Alkaloid among many others)) are joined not just by the orchestra but also by female co-vocalist Safa Heraghi, who has appeared on various other metal projects such as Devin Townsend's Z2, and she proves a wonderful addition, Tom's (admittedly sometimes rough) singing voice and usual grunts coming across perfectly here alongside her mix of strong (if not operatic) breathy cleans and the odd harsher moment. The immediate response to this version of Rex Irae is to wish all of those early Celtic Frost albums could have received orchestral backing in this style, because it works wonderfully! It's remarkable to go back and compare Tom's vocals here with the 1987 original version, for example - he hasn't audibly aged at all.

The ensuing thirty-minute-plus Grave Eternal will be a little more controversial, following on seamlessly from Rex Irae before the strings take lead atop a doomy backing from the band. It's here that the orchestra comes into its own, horns and brass providing a grandiose funeral march before dying away for a bluesy guitar solo. The piece moves away from metal altogether at points as it progresses, Safa's wordless vocals a beautiful initial guide as they flow atop the orchestration, but often the orchestral elements are left in their own right with Hannes' drums keeping near-constant backing percussion, which works tremendously and shows off another way in which this fantastically talented drummer excels. Female choral vocals here and there provide atmospheric drama, heightened by Tom himself popping up with chants alongside Safa. It grows more ominous as it continues and never grows dull despite the length, aided by the return of doomy riffing towards the end in a continuance of the Rex Irae theme.

As the vocals return and the Winter finale closes proceedings in suitably grandiose fashion, it's worth reflecting on how good Requiem as a whole is, far more dynamic and interesting than say, Nightwish's recent All the Works of Nature Which Adorn the World piece, and makes you wish that Tom would compose in the classical realm more often. That he's taken so long over this shows the care and attention put in, and it's good to hear it performed to such a high quality alongside the orchestra. It seems to be a one-off, the sort of event that those who witnessed it will remember for a long time and you can tell those present were suitably impressed from the limited crowd noise alone, brief bursts of applause the only mark that it is even live thanks to a near-perfect sound. Tom himself has said that this release is in memoriam of Martin Eric Ain and HR Giger, and it's a wonderful tribute, definitely recommended for fans of Celtic Frost, which all of you should be!

(The concert was videoed and is available on DVD, which was not viewed as part of this review but a Youtube sample is embedded below, a single viewing of which was enough for the DVD to be ordered by this reviewer!)