To celebrate its 100th anniversary, the Mendelssohn Choir of Pittsburgh tackled the grandest work of the composer who gave his name to community-based choirs ever after. The local ensemble, Pittsburgh's largest choral group and the city's oldest continuously running cultural organization, performed Mendelssohn's oratorio "Elijah."

It was an ambitious undertaking and, in many important aspects, a success.

Mendelssohn, who lived in the first half of the 19th century, was a champion of Bach and Handel. He adopted many of their techniques, but his oratorios are more ponderous, less swift in their dramatic momentum, and therefore more difficult to carry off than Handel's "Messiah" and "Israel in Egypt," say, or even the Passion settings by Bach.

For the big event Friday evening in Carnegie Music Hall, the Mendelssohn brought back Robert Page, its conductor of 25 years, who retired in 2005. Betsy Burleigh, the Mendelssohn's current music director, had some part in the preparation of this concert, although she did not conduct.

According to the program, the choir numbers 113, including a paid core of 19. A 12-person chamber contingent sings passages requiring further division of the voices. Sheer size (and, to a point, the volume to go with it) is one of the choir's strongest attributes, indeed a necessity in a work like "Elijah," which calls for operatic soloists of the first quality and a full symphony orchestra (here the rough but spunky 43-piece Academy Chamber Orchestra).

In addition, The Children's Festival Chorus (whose regular conductor is Christine Jordanoff), provided one of the evening's highlights in the exquisite a cappella trio "Lift thine eyes," sweetly sung from one of the theater's balconies.

Page certainly knows this score and, at 81, exercised admirable control of his choral and instrumental forces. There was admirable clarity of diction in the choral singing, although not much variety in tonal color. Page molded some nice phrases, particularly in softer moments, such as "He, watching over Israel." Favoring broad tempos, he lent majesty to "Holy is God the Lord" and drew out the epic quality of the closing chorus.

The biggest liabilities were among the soloists. Veteran Timothy Noble rendered Elijah's pronouncements with sensitivity, but his once booming baritone has deteriorated to a shell of its former glory. "Lord God of Abraham" was lovingly delivered, but lines such as "Call him louder!" lost their effect when vocalized with so little force, while the power demanded by "Is not His word like a fire?" and the middle section of "It is enough" was just not there.

Carnegie Mellon professor Douglas Ahlstedt retains a good deal of the vibrancy of his prime, and he, too, sang with intelligence. The sound, however, was on the dry side, and Mendelssohn's high tessitura pushed his sharply hewn tenor to its limits.

By contrast, the women -- soprano Laura Knoop Very and mezzo-soprano Quinn Patrick -- each brought a fresh, healthy quality to the music, although in Patrick's case not the heft in the low range to do justice to "O rest in the Lord," one of Mendelssohn's simplest and most affecting melodies.