Having musicalised the madness in the method of Wilde's The Importance of Being Earnest, what would that wackiest of composers Gerald Barry turn to next? Why, dear child, what else but the method in madness of Lewis Carroll's Alice books. Except that method is mostly discarded in the shards of nonsense extracted from Carroll, and to be found only in the musical art of compression.

Send in the paradoxes. Richard Rodney Bennett (1936-2012) had been so obsessed as a young man by music of the avant-garde, he would hitch-hike to Darmstadt to be in the same room as his (then) idols Berio, Maderna, and Boulez. He and Cornelius Cardew premiered important works by Boulez in the UK. And yet this was the same man who would later write, sing and play a cabaret song, “Early to Bed”, based on an endearing habit of Blossom Dearie.

Has there ever been a more pertinent time to revive the poetic mythologies of Brecht and Weill? The writer said that the good-life-for-dollars city of Mahagonny was not exclusively an American state of mind and should be set in any country where it's performed. But the inverted morality tale of The Seven Deadly Sins explicitly references seven American cities. And with lines like (in the Auden/Kallman translation) "If you show your offence at injustice, Mr Big will show he's offended", it's very much of the moment.

Most singers give recitals, and very nice they are too. But there are some – Bartoli, Florez, Netrebko, Terfel – who really put on a show. Mezzo Joyce DiDonato might just be the queen of this select band, and between the projections, smoke, sound effects, costume changes, lighting design and a solo dancer, her latest project throws down the gauntlet to any singer who thinks it’s enough just to learn the music and turn up in a clean frock.

At the conclusion of a year in which Britishness has come so resoundingly to the fore of the national debate – and with a play that at the time of its writing, 1605-6, was engaging with that concept no less urgently – the first impression made by Gregory Doran’s King Lear is how far removed it looks from any traditional sense of "British".

“Britain is a world by itself.” It could be the slogan of the year – and rather longer, probably – but the phrase comes from Shakespeare’s late romance Cymbeline. Its Act III scene, in which Britain announces that it is breaking its allegiances to the Roman Empire, surely can’t ever have played before with quite the nuance that Melly Still’s RSC production gives it. It premiered at Stratford in May, when the big Brexit question was still open, and now reaches the Barbican with redoubled relevance.

I could have sworn there was a spontaneous outbreak of phased coughing in the Barbican Hall on Saturday night, rapidly dissolving into laughter; such was the festive atmosphere at Steve Reich’s 80th birthday gig. This three-part epic attracted a full house, spanning the generations – from Michael Nyman, behind me mischievously proclaiming Reich’s debt to him, to students catching a glimpse of a legend.

What a relief to find Semyon Bychkov back on romantic terra firma after his slow-motion Mozart at the Royal Opera (performances speeded up somewhat, I'm told, after a sticky first night). On his own, dark-earth terms, there's no-one to touch him for nuanced phrasing, strength of purpose and the devoted responsiveness he wins from the BBC Symphony Orchestra - foot-stamping its approval at the end, a rarity - in Tchaikovsky and Rachmaninov.

Two personable musicians, who win on all fronts: at the pinnacle of their highly competitive and skilled professions, highly articulate, and perhaps unlikely partners in their art. In one corner, ladies and gentlemen, the composer, world-leading jazz trumpeter, teacher, head of Lincoln Center Jazz, the New Orleans-born Wynton Marsalis, 55. In the other, Nicola Benedetti, 29, the Scottish classical violinist, teacher and leading campaigning proselytiser for the importance of music in all spheres.

No living composer writes more compellingly for choir or for strings than James MacMillan (a surprisingly accepted "Sir" is now an optional addition to the name). This beautifully planned programme's first half gave us the former, a cappella choral music at its most masterly in the setting of the Miserere premiered by The Sixteen in 2009, before Vaughan Williams's Fantasia on a Theme of Thomas Tallis lay down the gauntlet for the latter.