G rateful Vineyarders will long remember the dazzling musical high wire act performed so superbly last weekend by Peter Boak and the inspired Island Community Chorus in their thrilling Spring 2009 concert.

Edgartown’s Old Whaling Church was stoked as the amazing Mr. Boak greeted the packed audience with a charming smile and a few words of welcome and excited introduction. Then he turned, raised his baton and deftly led his accomplished vocalists and musicians through two of the 20th century’s loftiest and most challenging choral compositions: Karl Orff’s Carmina Burana and Leonard Bernstein’s Chichester Psalms.

Programmed between the two major heroic pieces, a lush interval of six Brahms Liebeslieder waltzes lent a lilting romantic contrast to the quirkier rhythms and provocative harmonies of the Orff and the Bernstein.

At concert’s end, an enthralled audience jumped up and cheered. Soaring gracefully at such rarefied aesthetic altitudes, this director and chorus proved they can ascend as high as they please. The audience was ecstatic to share in their marvelous flights. People will be talking about this historic and victorious concert for a long time to come.

The text of Orff’s faux-ancient masterpiece, Carmina Burana, brims with robust and bawdy lyrics to celebrate the restlessness and energy of youth and spring. The verses, apparently composed by young men of the 13th century, resound with the old Boethian philosophy common to troubadour songs of that era, emphasizing romantic love and the mutability of fortune. Written in Latin, middle German and old Provençal and compiled in an illuminated codex several centuries before the printing press, the 254 diverse poems were hidden and preserved unseen in a Bavarian monastery until their discovery in 1803.

In 1935, the Bavarian-born Orff, a musical education specialist in Munich with a proclivity for the eclectic, began composing music to match 24 of the verses. Orff’s odd retro rhythms and primitive harmonies fit the quaint and often ribald lyrics of the largely unknown poems. The composer arranged an elaborately staged pageant for large orchestra, multiple choruses and soloists with stage directions to include large-scale presentations accompanied by symbolic visual images.

The first performance in 1937 brought Orff instant fame, and his secular cantata is now broadly recognized as one of the century’s foremost choral compositions. It’s haunting opening (and closing) anthem Fortuna Imperatrix Mundi (Fortune, Empress of the World) is often heard as a commanding chant in popular films, TV shows and commercials – idioms which rarely (let’s say never) feature lyrics in Ecclesiastical Latin.

Streamlining this Carmina for performance in the Whaling Church, Mr. Boak selected nine verses from Orff’s original 24 and used an orchestra boiled down to one extremely competent virtuoso — the redoubtable Garrett Brown seated at the Whaling Church Steinway — in front of one powerful, enthusiastic and exquisitely directed choir.

The result: magical and transcendent.

From the first discordant measure of Fortuna, the chorus swept the audience into an urgent and rollicking musical adventure which gripped the listeners from furious start to sublimely furious and compelling finish.

Instructed by Maestro Boak in his introductory remarks to follow closely the translated lyrics in the program, the audience’s eyes at first obediently darted back and forth from page to stage. But soon it was clear that the chorus was simply having too much fun up there as they sang – their faces lit with a fervent expressiveness and their bodies writhing and rolling rhythmically with the infectious music.

During the last boisterous march, Tempus es Jocundum (This is a Joyful Time), the chorus — comprised mostly of men and women whose adolescent romantic ardor bloomed multiple decades ago — all seemed to blush and roll with the words: “Oh, Oh, Oh/Totus Florio” (Oh, oh, oh/I am bursting out all over)! By this time, many in the audience had surrendered, left their programs beside them in the pews, and rolled in their seats to the music, right along with the singers. When the final chords of the Fortuna reprise resounded, Mr. Boak and his remarkable chorus and accompanist had, quite simply, triumphed in a rare and wonderful experience that brought smiles of amazement and resounding applause.

For the Brahms Liebeslieder, Garrett Brown invited his gifted brother Wesley to join him at the Steinway for four-handed accompaniment to the chorus. The waltzes had been previously performed in concert by the group, and the gentler, more familiar (and less taxing) Brahms harmonies cleansed and nourished the musical palate, charmed the audience, and yet offered some lyrical moments of 18th century romantic nostalgia. The mood in the hall mellowed in preparation for the Bernstein.

Commissioned for the 1965 Chichester Cathedral Festival, Bernstein’s Chichester Psalms have, like Orff’s Carmina, become central elements in the 20th century choral music cannon. Then 47, a world-famous composer with successes in concert halls, on Broadway and in Hollywood, Bernstein drew on his Jewish heritage by adopting beautiful Hebrew verses from five Psalms of the Old Testament into a three-movement cantata.

West Side Story had conquered Broadway seven years before, and in preparing the Chichester Psalms, Bernstein actually recycled elements he had explored in the original notebooks for West Side Story, which he had first intended as a Jewish-American gang story.

Traditionally, performers consider the Chichister Psalms some of the most demanding choral challenges in the repertory. The first movement is written in a weird 7/4 meter and the third in 10/4, separated into half-bars of 5/4. There are dicey harmonic calisthenics to master, such as the maintenance of a major 7th between tenors and bases. The tenor range requires a stretch beyond any conventional expectations.

The Island Community Chorus tackled all these challenges, took up the painstaking task of subtle Hebrew pronunciation, and then mingled their final choral product with dramatic harp and percussion passages. The work of preparation must have been immense, because the performance in the Whaling Church was absolutely refined and exquisite.

When Mr. Boak and the chorus set off on the first clashing cadences — “Urah, hanevel, v’chinor!” (“Awake, psaltery and harp!”) from the 108th Psalm, the effect was pyrotechnical. Bernstein in his early directions had emphasized the centrality of the harp as part of the Hebrew tradition, and harpist Sandra Bittermann’s crisp articulations gilded the bouncing inflections of the voices deliciously. Brian Weiland’s deft percussion work (including some nifty bongo fingering) was indispensable to the overall effect. Again, Garrett Brown was rock resplendent in this jubilant movement as the joys of the 100th Psalm declare God’s truth to endure for all generations (“V’ad dor vador emunato.”)

The second movement featured the remarkably mature and textured tones of Hannah Marlin, a junior at Martha’s Vineyard Regional High School. This section, celebrating the 23rd Psalm’s declaration of serenity and faith — “I will fear no evil, for Thou art with me,” (Lo ira ra/Ki Atah imadi) — gives way to the alarming and rhythmically unsettling “Why do the nations rage?” (Lamah rag’shu goyim?) delivered by the tenors and basses.

The tranquilly evolving third movement, eventually a gentle and soothing waltz, offers some signature Bernsteinian harmony as the dulcet voices declare from Psalm 131 that “Surely I have calmed/And quieted myself” (“Im lo shiviti/V’domam’ti”). Finally the entire chorus and harp at last blend into a lovely unison and sustained oath from the Psalm 133, “For brethren to dwell/Together in unity” (“Shevet ahim/Gam yahad”).

As the final unison G faded softly, the audience took in a deep breath and cheered with glee. Loudly applauded bows were taken by soprano Joyce Maxner, Alto Caroline Evans, Tenor Kevin Ryan and Bass Steven White. Ms Marlin was loudly cheered, as well as Ms. Bittermann and Mr. Weiland. Mr. Brown received sustained recognition, and of course Mr. Boak’s proud smile was treasured by the audience. He had walked the high wire with all his wonderful, talented friends.

What can they possibly come up with to top this one? We’ll be anxious to find out.