Lontano/De la Martinez, The Warehouse, London Exaudi, Wigmore Hall, London

Fourth London festival opens with a killer US opera, and there’s glorious suffering in madrigals

When the humble shepherd comes a-calling on the icy princess, fairytale convention dictates that the ardour of his honest love melt her frozen heart, and a wedding ensue. But the bleak storyline of John Harbison's chamber opera Full Moon in March, inspired by Yeats's play (not surprisingly, rarely performed) and staged for the fourth London Festival of American Music, denies the redemptive happy ending.

Harbison's ambitious swineherd is a filthy, muscular creep, the princess he woos a spiteful despot. In their hateful world are only two malign attendants and the princess's alter ego, a lascivious dancer. So with not a glimpse of loveliness on stage, it rests with the music to reveal beauty in this hostile landscape. And it is there, in the arching, aching lines of Jeremy Huw Williams's meatily sung Swineherd, reminiscent of Britten's Peter Grimes, longing poisoned by lechery proving lethal.

Those so squeamish they hide behind the sofa when George Osborne comes on screen might recoil at the climactic pas de deux with the severed head of the Swineherd, and fatal kiss on lifeless lips. But Gwen Elfyn Jones's low dance to the death was a mesmerising spectacle, egged on by Harbison's relentless score and dark orchestration, the insistent bass clarinet and Barnaby Archer's percussion presaging a terrible end. Matthew Deeley's design for Carmen Jakobi's production echoed the narrative's cool oriental clarity as well as the characters' commedia singularity.

"Every aspect of this opera is environmentally sustainable," read the programme, impressively if incomprehensibly. For sure, the word "cruel" is much recycled, and this is, at many levels, a nasty piece. But then March, not April, is the cruellest month, and nothing good ever came of it, except the clocks going forward again.

All three of the short pieces that opened the evening by the group Lontano in The Warehouse were UK premieres, and all paid tribute to earlier composers. Arthur Levering's Still Raining, Still Dreaming, dedicated to Toru Takemitsu and nodding at Jimi Hendrix, summons all the colours of the rainbow. In a wonderful moment of instrumental synergy, a double bass bow is drawn up the keys of a vibraphone, the frail bat squeak morphing seamlessly into the woodwind line.

Aleksandra Vrebalov's Passion Revisited for Piano Trio, based on an aria from Bach's St Matthew Passion, is a richly romantic invention suspended from the opening and closing thread-like notes. Sophie Harris's sumptuous cello playing turned this into a special occasion and the dependability of pianist Mary Dullea – here as throughout the evening – made you wish that, if ever you missed your footing, she would be the person at hand to catch you. Rand Steiger's 100th birthday tribute to Elliott Carter is a work of such complexity and virtuosity you can only plunge in and enjoy the tumbling, maybe catching a glimpse of some of the dozens of musical references among the breakers.

Odaline de la Martinez both conducts Lontano and is artistic director of the annual festival, and this total immersion in American music is a boon. Next year's programme is something to look out for.

Weeping, crying, grieving, dying … Exaudi's idea of a good time comes laced with pain aplenty. And yet an evening in the company of these eight singers at Wigmore Hall, celebrating 10 years of exquisite agony in music, was a splendidly upbeat affair, with many cheerful interventions by founder and director James Weeks and a clutch of new commissions, the first of an open-ended project to write a madrigal book for the 21st century.

While English fa-la-la madrigals are largely winsome noodles, Italian madrigals, Exaudi's natural habitat, are mini-operas. Monteverdi was on his way towards staging his, arguably the first, opera at Mantua when he dedicated his third book of madrigals to Duke Vincenzo Gonzaga, and his account of Rinaldo's leaving Armida (which will form the basis of a Handel opera a century or so later) distils in only three stanzas all the heat of desire and chill of rejection.

Singers who can invest this luxurious howl with such colour, and then premiere Larry Goves's bleached and hypnotic "Sherpa Tensing …" , seem capable of anything. Soprano and co-founder Juliet Fraser's burnished silver and the oaky bass of Jimmy Holliday are particularly lovely, but it's the ensemble work that amazes, making Exaudi a single instrument of seemingly infinite powers.

In Salvatore Sciarrino's three madrigals from 2008, five singers swoop between notes, exhale voicelessly and wobble their lips, adding pattering finger clicks in dazzlingly complex cross-rhythms. But nothing is more outlandish than the other-worldly, almost unhinged dissonances of Gesualdo (born 1561). "La vita lascio e me ne vado a morte", sigh Exaudi with relish: "I must part from life and die." Long may they do so.

Next week

Anna Picard heads to Wexford

Critic's choice

Start them young on opera with Netia Jones's staging of Oliver Knussen's Where the Wild Things Are and Higglety Pigglety Pop, the Barbican's double bill half-term treat (Sat). Also in London, Osmo Vanska conducts the London Philharmonic Orchestra in Rachmaninov's stirring Symphony No 3, and Christian Tetzlaff joins the party to bring his characteristic dynamism to Dvorak's Violin Concerto at the Royal Festival Hall (Friday).