Jake Heggie’s 2000 opera “Dead Man Walking” – based on the memoirs of Sister Helen Prejean and inspired by the film of the same name – hardly conforms to operatic standards. An intersection of “Porgy and Bess”-like motifs, rock opera recitatives, and the echoes of New Orleans jazz, it treats the opera template with a moderate respect: scant arias and duets that favor the “parlato” style of speaking rather than singing, the hazy reflection of a theme by the chorus, predictable repeats of an ominous phrase. Altogether the music is arranged in a wavering form that oscillates continuously between one genre and a strikingly contrasting counterpart. And yet it all appears to be a choice on Heggie’s own behalf: one stubbornly intent on stimulating the effect of entropy.

At Odds With Itself

It’s undeniably a logical approach. Most of the action takes place on death row at Louisiana State Penitentiary, where cellmates wrangle with their guards in brawls and hurl loud curses when a nun enters the ward. The nun in question – Sister Helen Prejean – has become a pen-pal to Joseph De Rocher, a prisoner convicted of a teenage girl’s rape and the murder of both her and her boyfriend. The opera’s plot revolves around the real-life story of their unexpected friendship and the arduous, exhausting route she takes to both convince him to confess and grant him her forgiveness. What’s palpable throughout the music nonetheless is a deficiency of valleys dug to offset peaks; an absence of the very peace and indispensable serenity of which Sister Helen is always singing. Here the eerie shriek of a motif on strings splinters the regulated rhythm of the brass, or else percussion cleaves the brisk lull of the flutes’ motif with brusque inelegance. So while the crucial theme is humans’ need to live in harmony and give forgiveness, predominantly what the work projects is violence.

Throughout the score the instrumental sections’ parts square off against each other constantly. Their in-fighting thereby constructs a bulky border the conductor has to straddle – forced to symbolize the chaos without letting the ensemble collapse into a clatter of resounding metal rubble. In this instance at the opera’s UK premiere in a concert staging at the Barbican in London, Mark Wigglesworth controlled most of the timing of the entrances with slick and preordained commands; distributing each stop and start with his own metaphorical control dial. There were occasions in which brass went temporarily awry and strings lost the upper layer of their flawless tone – but it was difficult to differentiate between the score’s purported moments of disorder and infrequent lapses.

The Star of the Night

More than the music or libretto, Joyce DiDonato’s vocal choices dispersed puffs of smoky horror in the ambiance. In the confines of this concert-staged rendition with scarce props and set design, DiDonato’s hunched shoulders and inelegant gesticulation easily embodied the fatigued existence of this Southern nun; a woman who spends hours helping disenfranchised (and occasionally violent) folks. In the mosaic of all her variegated roles, we haven’t much heard DiDonato sing the lines of gospel music – a genre onto which this opera sometimes shines a spotlight. She zig-zagged through the languorous melismas with an effortless pizzazz; they were no less endemic to her than the thin spaghetti ribbons of repetitive coloratura. Of all the cast, she was the only one to represent slow-boiling, simmering realizations with the incremental, tentative crescendos that she exercised on notes; as always thickening vibrato on her instrument without abrading any of its tone. When uttering the phrase “I’m sorry” to the parents of the children murdered at the convict’s hands, she treated every repetition with a new approach, making her guilt and compassion both palpable.

Brutality Embodied and Sung

In the role of sentenced murderer Joseph De Rocher, baritone Michael Mayes effuses a defiant arrogance, barbarous boldness, and wide-ranging physicality. His instrument is loaded with a prominent vibrato, quivers on the voice so evident they stick out like the scales across a fish. On one hand, this lent his incarnation of the character blunt authenticity. Menace fused with chronic fear of dying was as audible as it was visible. But on the other hand, there were moments when he let a strong desire to portray the personage outweigh the vocal line’s security. At times he hindered the starts and ends of phrases – sliding on to them or letting them drop off unceremoniously. He cracked when closing the duet with Sister Helen, “The truth will set you free.” Although there’s no doubt that an actor in a play would have performed the role with similar inflections, this purports to be an opera. While the recitatives are so thickly strewn that the work’s genre is questionable, well-sustained vocal lines must – give or take a fine creative inch – be lodged in place.

A Smorgasbord of Vocal Variety

Measha Brueggergosman, in the role of Sister Rose, possesses a low-lying, thick soprano that she wields with elasticity and ease. Though at times perilously shaky at the top, her voice is a rare mixture of distinct corporeality and supple flexibility.

As Joseph’s mother, Mrs. Patrick De Rocher, Maria Zifchak offers a thin and at times restrained mezzo-soprano apt at conveying her unending anguish. While she occasionally cedes to instability in the top register, Susan Bullock and Susan Bickley, as the murdered children’s mothers Kitty Hart and Jade Boucher respectively, are more prone to tremulousness in their singing. In part because of this, the parents’ cascade of reprimands towards Sister Helen at the end of the first act – “You don’t know…” – devolved into a slightly off-key (albeit well-timed) quartet.

As Father Grenville, Michael Bracegirdle performed his role with emboldened self-righteousness coursing through the surface of his steely, unbreakable voice. James Creswell, in the part of prison ward George Benton, loaded his well-regulated instrument with a portentous emphasis that seemed to be inherent to most singers through the course of this performance. Every performer’s diction was clear-cut and the majority of Southern accents were infallible.

Yet on the basis of its very nature, Heggie’s opera struggles to upend its listeners with the relentless poignancy it strives so hard to stir. Countering the characters’ life-changing revelations, fast-switching musical motifs ensure the audience’s ears are turned to the direction of abrupt changes in timbre, key, and pace that take-up so much intellectual room, they leave too little to absorb only the storyline. While the majority of music pays homage to 1920s jazz or newer American music akin to Bernstein’s “Trouble in Tahiti,” manifest citations – such as the brass’s iteration of the first two chords of Elvis Presley’s “Jailhouse Rock” after the Sister mentions him – make for an essay that contains one quote too many. While the performers filled the atmosphere with unavoidable lugubriousness, it was perhaps the final layer of a stack of overlapping, interleaving slides derived from a collection of contrasting genres, themes and stories. The overall effect, therefore, was undermined by disarray – albeit a most haunting one.