Preview: Viva Voce at St Patrick's Cathedral

It was 1985 and, determined to sustain the choral exhilaration experienced with the University Singers and the National Youth Choir, John Rosser and a group of fellow singers formed Viva Voce.

A quarter of a century on, Viva Voce can rightly claim it is the city's (and possibly the country's) most versatile chamber choir. As far as the music goes, it has always been a matter of the mix, says Rosser.

"The choral repertoire is full of three-minute wonders and miniature masterpieces," he explains. "One jewel after another without a necklace to join them together."

Twenty-five years of linking these gems in various "concept concerts" has earned the choir a loyal audience. Looking back over the various compilations, Rosser is most proud of Viva Voce's 2002 Oh Boy concert.

"It was made up of pieces to do with men and material was a lot harder to find than if we'd done a concert about women. After all, male composers have written about women forever."

The highlight of Oh Boy was Eric Whitacre's When David Heard, "a stunning piece of American choral music in which the composer really pushes himself to the limit.

"For 12 minutes you contemplate the enormity of a father being responsible for the death of his child with dramatic block chords and Pinter-like silences."

Tonight's Denial, Decision, Deliverance is another ambitious venture for Viva Voce - and an annual loosening of the budget strings means an orchestra is brought on board.

The Denial of St Peter and Judgment of Solomon, a pair of miniature oratorios by Marc-Antoine Charpentier (1643-1704), may be Auckland premieres.

For Rosser, Charpentier is "a wonderfully dramatic writer. He treats these religious texts in such a theatrical way that it's a tragedy he only wrote one opera, Medee."

Rosser continues with a gripping description of how his choir will divide into 12 haranguing voices to badger St Peter and how the eternally wise Solomon will be confronted by the true and false mothers, sung by soprano Emma Roxburgh and countertenor Stephen Diaz.

But the truth is that French Baroque music has an alarmingly small profile in this country.

"We know Monteverdi and Handel and nothing in between," Rosser says. "Yet French music of this period is so full of the joy of the dance and of their own language".

He is confident tonight's soloists, who also include Morag McDowell, Matt Landreth and Andrew Glover, will impress in this music from the time of the great Sun King, Louis XIV.

"It's important that singers understand what this music is trying to do," he explains. "These works are not about the human voice per se, but the shape of the music. Human emotions fit within that structured shape."

Above all, Rosser does not want his singers to hold back when it comes to the emotions.

Casting Baroque is "not a matter of finding skinny white voices which too many professional British groups do. I've heard so many baroque singers who don't know what passion is".

Completing tonight's programme is Faure's Requiem which features baritone Matt Landreth and boy soprano Mitchell Hageman, whom Rosser discovered in a Kristin School production of Oliver.

It may seem a startling leap from Consider Yourself to Pie Jesu but for a philosophical Rosser: "That's what reigning boy sopranos have to do."

Having sung this work many times before, both as chorister and soloist, this is the first time Rosser is conducting what he describes as a "Requiem of Deliverance".

"Most requiem writers convey the message, at least in the Dies irae, that you've got something to worry about when the great judge comes to do the final trial," he laughs.

"There's nothing of that with Faure, who almost hides the Dies irae. For him death was a transition to something better, a Requiem of Deliverance."

What: Viva Voce - Denial, Decision, Deliverance

Where and when: St Patrick's Cathedral, tonight at 7.30pm