Bruno Walter's Mahler has a special status which seems likely to survive the misgivings of revisionist critics. Historically speaking, there is no gainsaying the authenticity of this Ninth. Walter himself conducted its première, the work is dedicated to him, and this was its very first commercial recording, captured on the personal initiative of producer Fred Gaisberg and originally issued on ten 78rpm discs. Mike Dutton's reissues are not always prodigiously annotated, but we get precisely what is appropriate here - Gaisberg's own 1944 Gramophone article - to set the project in context. For Naxos's transfer engineer, Mark Obert-Thorn, the numbering of the matrices hints that Gaisberg may have taken down more than the one-off concert of legend. But whatever the case, no one is disputing that we are in Vienna's Musikvereinsaal with Mahler's old orchestra only a few weeks before the Anschluss.

The sense of looming catastrophe is palpable in more than one respect: this is music-making in which scrappiness and fervour are indissolubly linked, an emblematic last gasp of the old world that Hitler would shortly sweep away. Few modern performances offer more intensity in the first movement (Bernstein and Rattle perhaps?); none do so while maintaining Walter's singing line. Nor is the conductor's forward thrust in the finale much imitated, except perhaps by Barbirolli in what was one of his most passionate interpretations. All in all, there is little here to support the caricature of Walter as anodyne traditionalist, and it would be a hard heart that characterised the proceedings as merely sloppy. Even the Rondo-Burleske is launched in suitably demonic, if perilous, style. It is Walter's 1961 studio recording, the first to be taped in stereo, that you might find too relaxed in feeling, although its surprising linear clarity is superbly projected in its current CD incarnation.

Walter's 1938 set communicates differently in the two transfers under review. The lower-level Naxos option is perfectly acceptable: there's some opening out of dynamics but nothing that calls attention to itself or betrays the 'rich mass and depth' of sound to which Gaisberg refers. Whereas Mike Dutton takes real risks, bringing the orchestra - and the bronchial audience - that much closer to the listener. Such alchemy may be controversial. Here at least it works so well that you sometimes feel as if you've stumbled on a particularly scrappy yet committed youth orchestra concert on BBC Radio 3 - the effect is that 'modern'! While the boost to the upper mid-range gives rise to some fierceness of tone, the gain in immediacy and clarity of detail is striking. I do prefer the way Obert-Thorn retains some residual background hiss between movements, promoting the illusion of concert hall continuity. But it's a small point when the original surface noise is filtered to near-inaudibility in both transfers.

How to sum up? Some listeners will, I think, be taken aback by the technical lapses of the pre-war VPO (the third movement unsurprisingly comes close to collapse). And it's true that one could make out a convincing case for the 'superiority' of any one of the accounts listed above. Nevertheless, for all but the pedants and the purists, the Dutton restoration is a must have at its new low price. So vivid a document won't be losing its 'classic' tag just yet.