I can’t think of many song discs that have left me with such ambivalent feelings as this. Live and on record, Florian Boesch is a charismatic, involving performer who always compels you to listen – and think. But even more than on his previous discs, his default setting tends to be a confidential whisper, sometimes shading into speech-song. At anything less than mezzo-forte a ‘bowed’ legato is at a premium. From the opening Dichertliebe sequence Boesch’s singer-poet sounds dazed, traumatised, with phrase after phrase trailing away disconsolately. Already the bliss of springtime has become irrevocably blighted. Even the hectic tongue-twister of ‘Die Rose, die Lilie’ is anxious and regretful rather than elated.

When he chooses, Boesch unfurls a handsome, darkly resonant baritone, whether in the majestic evocation of Cologne Cathedral in ‘Im Rhein, im heiligen Strom’ or a sardonically incisive ‘Ich grolle nicht’, its climax magnificently clinched by Boesch and the ever-illuminating Malcolm Martineau. From here on the baritone cultivates extremes of slowness (above all in a trancelike ‘Hör’ ich das Liedchen klingen’) and disorientated reverie. Just when you think his whispered intimacy cannot get any more hushed, as in ‘Am leuchtenden Sommermorgen’, it does. Even the mock-jaunty ‘Ein Jüngling liebt ein Mädchen’ is sung in an abstracted undertone, until Heine’s searing punchline ‘Dem bricht das Herz entzwei’. Boesch deploys his full, firm resonance in the stoical march of the final ‘Die alten, bösen Lieder’, before the revelation of ‘Ich senkt’ auch meine Lieder’, the notes barely breathed. After this catharsis Malcolm Martineau gives a masterclass in the phrasing and voicing of Schumann’s healing postlude.

‘Sing a true legato line.’ ‘Give Schumann’s melodies their due.’ Yet despite my own silent mutterings, time and again I succumbed to the imagination and concentrated, almost claustrophobic intensity of Boesch’s waking-dream Dichterliebe, in symbiotic partnership with the hypersensitive Martineau. If you’re in sympathy with the baritone’s style you’ll warm, too, to his singing of the Kerner Lieder. Beginning with the Schumannised Bach of ‘Stirb’, Lieb’ und Freud’’, Boesch has, reasonably enough, reordered these songs to create what he dubs a ‘dramatic and emotional progression’: the poet-singer’s desolate wanderings and gradual withdrawal from the world after the girl he loves has taken the veil.

Predictably by now, Boesch delivers the epic ‘Stirb’, Lieb’ und Freud’’ in a haunted whisper, further softening his tone for a ghostly rendering of the novice’s words. Even in the extrovert, al fresco ‘Wanderlied’ and ‘Wanderung’ the baritone avoids lederhosen heartiness. In ‘Wanderung’ he immediately creates a sense of wide-eyed wonder, abetted by Martineau’s supple pianism, ‘light and delicate’, as Schumann requests. The potentially maudlin seance song, ‘Auf das Trinkglas eines verstorbenen Freundes’, is kept well flowing, with singer and pianist palpably feeling the mysterious harmonies at ‘Still geht der Mond’. Happily, too, Boesch chooses a mobile tempo for the glorious melody of ‘Stille Tränen’, phrasing in generous, arching spans, without ever overblowing (always a temptation in this Italianate bel canto!). I only wish he had allowed us to savour the beauty of his tone more often.

Anyone for whom a liquid singing line and even emission of notes are paramount will give this disc a wide berth in favour of the self-recommending recordings of both cycles by Fischer-Dieskau with Eschenbach (DG, 3/79), Matthias Goerne and Erich Schneider (Decca), Christian Gerhaher and Gerold Huber (Sony, 2/19, 10/21) and, in the Kerner Lieder, Simon Keenlyside with Graham Johnson (Hyperion, 3/98). I can’t completely shake off my own intermittent frustrations. But those willing to take Boesch on his own, idiosyncratic terms – song as heightened speech – should find much to enjoy and ponder.