It’s been a busy couple of months for Berlioz’s Requiem in London. First there was Sir Colin Davis’s June performance at St. Paul’s, with the reinforced London Symphony Orchestra’s brass bands arrayed around the dome. Now, on an unofficial Big Choral Weekend at the Proms there was this valedictory effort from the BBC National Orchestra of Wales and their outgoing music director, Thierry Fischer.

Like so many of the compositions that work best in the Royal Albert Hall, Berlioz’s Requiem depends on a spatial arrangement of the performers. This isn’t just true of the music, with its built-in silences for reverberations, its four brass groups positioned around the rest of the orchestra, and the time it needs for the sheer weight of sound to settle down. It’s also true of what the Requiem represents, its traditional text wedded to a Revolutionary aesthetic that at once deals with the life and death of the individual and the idea of a new Nation (France) on the edge. This is not a Requiem that commemorates the dead so much as acts out their journey, bringing together the individual and the community (symbolised by the vast forces) in a giant music-drama rather than anything more recognisably pious. Indeed, even without knowledge of Berlioz’s atheism it would be clear that there is a somewhat hollow centre to this Requiem: there is a distant quality to its belief, one that remembers what faith must have been like but one which cannot, for whatever reason, feel it again.

The Royal Albert Hall would ordinarily be the ideal venue, but Thierry Fischer chose to underplay his hand by stationing two units of brass around the cramped strings on the front apron, arraying the rest across the rear. Berlioz’s instructions could be interpreted that way, of course, although they imply a greater space between the orchestra proper and the other brass than this squashed arrangement. Yet prommers this season have already witnessed innovative use of space (for instance in several of the Boulez works performed by members of the West-Eastern Divan Orchestra), and it seemed a pity not to embrace one of the few acoustic upsides of this hall – particularly as the detailing and effect of the brass deluges then got lost in a block of noise, overwhelming the choir's already weak diction for good measure.

Slightly offish balances were indeed one of the main problems of this performance, although the conductor’s task is admittedly almost impossible. More worrying were immediate ensemble issues in the opening Introit, not helped by the tentative flatness of the BBC National Chorus of Wales, the Huddersfield Choral Society, and the London Symphony Chorus. There were some very fine moments from these combined choirs, particularly in the Quaerens me and the Offertorium, but too often they sounded stretched by Berlioz’s challenging writing, or one step removed from the emotional demands of the text. Toby Spence likewise struggled with the high-lying tenor part in the Sanctus, although his previous recording of this role suggests this was simply an off night.

Thierry Fischer’s command of the piece as a whole was not as firm as might have been hoped. There were fine moments, to be sure, and there was an excellent sense of human inadequacy to be found throughout, especially at the close of the Tuba mirum. The whipping Lacrimosa had a more recognisably Berliozian sound than Fischer often drew from these forces, as did an outstandingly plaintive Offertorium. There was a genuine sense of love here for the souls of the faithful trapped in the purgatory intimated by the rocking, two-note singing, and a hope in the light promised to them. (How fortunate that this performance was at its best in the emotional centre of this work.) As much as one wondered why the strings played so often and so oddly without vibrato, the BBC National Orchestra of Wales played superbly. Despite (or perhaps because of) their numbers the brass proved well-blended, with a very bright tone not unsuited to the fires of Judgement and the light of redemption. There was some fine wind playing too, particularly from the flutes and oboes.

On the whole, though, much more could have been found from this work. Fischer never cosseted Berlioz’s writing, as Davis does to such effect, which brought out this composer’s inherent weirdness. That is a valid and indeed intriguing view, but it was never really followed through. In tender moments like the chanted Kyrie and the prayerful Quid sum miser there needed to be greater devotion – to something, even if not to God – and in more fiercely dramatic sections like the Dies irae and the fugues of the Hosanna more drive and structural cohesion were needed to hammer the message home. In general, this was all rather underdone.