‘A lazy, coarse, shifty character, cunning as a fox’ was Mozart’s crisp verdict on Josepha Weber in a letter to his father of December 1781, when he was eager to promote his future bride Constanze as the flawless Cinderella among the Weber sisters. Aloysia, his first love, was simultaneously branded ‘false, malicious, and a coquette’. As so often, we sense that Wolfgang was merely telling the ever-suspicious Leopold what he wanted to hear. He remained friendly with Josepha and Aloysia, professional singers both, writing arias for them that exploited their coloratura prowess. Most famously, he created the role of the Queen of the Night for Josepha Hofer, as she now was, at Schikaneder’s Theater auf der Wieden. Eager to capitalise on the runaway success of Die Zauberflöte, Schikander then commissioned Peter von Winter to composer a sequel, Das Labyrinth, for which Josepha reprised her role of the malignant queen, complete with vote-catching top Fs.

In tandem with the musicologist Christian Moritz-Bauer, the young German soprano Sarah Traubel has devised a tribute act that embraces many of the roles Josepha sang at the Theater auf der Wieden. Amid familiar Mozart we get, inter alia, a brace of arias by the now virtually forgotten Bolognese Vincenzo Righini, an aria by Jakob Haibel, who later married Josepha’s youngest sister Sophie (as Leopold feared, there was no escaping those Weber girls), and a solo from Paul Wranitzky’s magic opera Oberon, a possible influence on Schikander’s libretto for Die Zauberflöte. It would be nice to report revelations here. But for all their fireworks and (above all in the Winter and Righini arias) colourful orchestration, there remains a vast gulf between Mozart and these assorted Kleinmeister in harmonic inventiveness, melodic allure and sheer compositional sophistication. Mozart invariably makes coloratura an agent of drama and/or (in the Queen of the Night’s arias) parody. In other hands – not least those of ‘that idiot’ (Mozart’s words) Franz Süssmayr – it too easily becomes mere vacuous display.

Sarah Traubel certainly has the vocal equipment to tackle these coloratura showpieces. Her bright, ‘pingy’ tones and agile technique immediately impress in Haibel’s mock-heroic aria proclaiming women’s sexual power (‘Men are putty in our hands’) and a Righini aria with obbligato flute and oboe. Traubel is never less than accomplished, soaring confidently above the stave, pitch-perfect in the staccato scales and arpeggios in which Josepha specialised. Yet in the Mozart arias, especially – where other sopranos inevitably echo in the mind’s ear – she never quite satisfies. The Countess’s two solos (which Josepha performed in German) need more tonal depth and warmth than Traubel can muster; and in a gamely sung ‘Martern aller Arten’ from Entführung she is not the first soprano to sound like an over-promoted Blonde. Both here and in the Zauberflöte arias she is prone to moments of shrillness (her final top B flat on ‘Hört’ in ‘Der Hölle Rache’ sounds strained rather than commanding) and never makes enough of her consonants – a recurrent problem throughout her recital, in both German and Italian.

These provisos apart, there’s plenty to admire in Traubel’s snapshot of Josepha’s repertoire at the Theater auf der Wieden. The Prague orchestra, slightly backwardly recorded, are faithful accompanists, though more than once Jochen Rieder sets a tempo that can’t be sustained when the rapid coloratura kicks in. The ordering of items can seem random – why, for instance, do the two Queen of the Night arias not follow one another, ditto the Countess’s arias? In compensation, there’s an informative note from Marcus Felsner that neatly summarises Josepha’s career and, crucially, sets each number in its dramatic context.