‘Subtle’ is the adjective used on the inlay card for this concluding volume of Mahler’s reorchestrations of Schumann’s symphonies. Well, there’s subtle and there’s subtle. The snarling muted horns at the climax of the first movement of the Rhenish (5'36") are anything but subtle; ditto the unison horn quartet, marked fff and Schalltrichter auf! (‘bells up!’), on the final page of the Fourth. Then again, there are countless moments of great sensitivity when Mahler refines the effects at which Schumann was aiming, clarifies lines and thins out the full-fat scoring for wind and brass. There’s nothing here quite as audacious as Mahler’s wholesale reharmonisation in the closing bars of the Second Symphony but there’s still plenty that will catch the ear of all who love these works.

The validity for a 21st-century audience and efficacy of Mahler’s tweaks were at least partly addressed in my review of the companion volume (12/22). Needless to say, exercises such as this exert a fascination especially upon those of us who take a slightly nerdy interest in musicological minutiae and find angels as well as devils in the details. There’s no denying that Marin Alsop has the measure of these works and her belief in the project shines through in these performances. The fact remains, though, that her Vienna radio ensemble is outclassed by the Leipzig Gewandhaus Orchestra under Riccardo Chailly (Decca, 5/07). Alsop’s readings are assuredly satisfying but Chailly’s boast playing of a degree of security and imagination, and he displays a grasp of the architecture and cumulative effect of these symphonies, that are unmatched by the Vienna players.