BOSTON — The first shock is the stage.
The bare-boned, elegantly paneled stage of Symphony Hall is adorned with only one bench, three music stands, four tiny microphones, and a table in the back holding a cola, a glass of wine, and a cup of tea.
It's about as far as you can get from the equipment laden stage of a rock show — such as the Guns N' Roses show across town at the Garden.
Audience attire ranges from tuxedos to T-shirts, but mostly the age and dress reflects that on the stage — Elvis Costello, 38, and the slightly younger members of the classical world's Brodsky Quartet, with whom he's made his latest collaboration.
Of all the stages Costello has played in this town, as the enduring angry songwriter from rock's new wave era 15 years ago and, most recently as the embittered, bearded popster on his Mighty as a Rose tour, this is surely the most unexpected.
The man who once recorded under the name "The Imposter" seemed to sense the suspected fraud as he marched on stage with the string quartet. Yet he couldn't conceal his own grin Thursday as the audience poured out its applause.
Pop has flirted with classical pretensions before, dating back to such novelties as B. Bumble & the Stingers' version of the "William Tell Overture" as the "Bumble Boogie" in 1961 and the Toys' hit remake of Bach's "Minuet in G" as "Lover's Concerto."
More recently, David Byrne and Paul McCartney have issued ambitious orchestral works that have generally alienated and mystified their pop audiences.
But Costello's achievement on his most recent work, The Juliet Letters, and on this extremely limited tour is in plying his pop songwriting skills within the structure of a quartet, made up of smart young people who have also been fans of Costello.
The Juliet Letters is truly a collaborative album, with mutual input from the quartet on lyrics and music.
Inspired by an item in the press about a professor in Verona
who answers letters sent to the fictional Juliet, the music is a collection of various letters, some of which are inspired by the late Miss Capulet, some not.
Costello, warmed by the welcome, was chatty and at ease in the format, which had already played three of its four U.S. dates, as he explained most songs in terms that added depth to their meaning.
In wire-framed glasses, sportcoat and leather-bound libretto, Costello struck the image of Lou Reed on his last two tours, presenting serious works from beginning to end, chamber music-style.
But while those works were still rooted in rock, these fly into classical flurries obviously new enough to the audience to have them cheer specific bowing techniques.
The quieter format not only highlighted the lyrics but also Costello's voice, which was astonishing in its power and vibrato. Without his usual guitar, he was free to use his hands and boxier body to emote, playing the clowning aspects of an aunt denying her money-grubbing heirs in "Dead Letter," the one song played twice.
And if anything, his live performance improved on the rigorous album vocals, delivering leveling blows on such numbers as "Taking My Life in Your Hands," which finished the first set, or the affecting final, "The Birds Will Still Be Singing."
Even so, the two main portions of the program served to introduce the surprising selections in the three encores.
Not only was there a new song unveiled, indicating a further collaboration, but there were inspired arrangements of an old Irish song, in honor of St. Patrick's Day, an obscure show tune, along with rock tunes as diverse as the Beach Boys' "God Only Knows" to Tom Waits' "More Than Rain." And Costello gladdened the hearts of die-hards by throwing in a heart-stopping rendition of his own "Almost Blue."
Costello is notorious for dabbling in other genres, including country, folk and pop. One album of standards is ready for release; he dashed off an entire album of songs in a single weekend for Transvision Vamp singer Wendy James, spending as much time as most would doing a crossword puzzle.
But his success in this venture has whetted the appetite for more intelligent, challenging music in venues where you needn't stand on chairs all night or show your appreciation by flicking a lighter.