PITTSFIELD — Name this string quartet: It is noted "for its beautiful tone, its perfect integration, its impeccable taste, its careful phrasing, character and style, and above all, its depth of interpretation, power and sweep."
It could be any of numerous ensembles making the rounds during the current boom in quartet playing. Actually, it's the Budapest quartet as described in Joseph Wechsberg's essay collection "Trifles Make Perfection."
The description could particularly apply to the Emerson String Quartet, which returned to South Mountain Sunday afternoon at the beginning of its 40th-anniversary season. As the senior quartet today, the Emerson occupies the place the Budapest held as the reigning quartet during much of its 50-year existence from 1917 to 1967.
The now venerable Emerson enjoys the dual benefit of continuity and fresh blood. Violinists Eugene Drucker and Philip Setzer, who alternate positions, have been with the group from the start, while violist Lawrence Dutton and cellist Paul Watkins are recent additions. To celebrate the anniversary, the group's entire recorded repertoire has been reissued as a 52-CD boxed set on Deutsche Grammophon.
Recalling the Emerson's long history at South Mountain in a brief talk from the stage Sunday, Setzer thanked the audience for its support over the years. The feeling was clearly mutual.
The Emerson seemed a quartet transformed on its return. Its playing was refined almost to the point of understatement, illuminating works by Mozart, Shostakovich and Dvorak.
A comparison with the Dover quartet, which preceded the Emerson by a week (and also played Shostakovich), seemed inescapable. The two groups are comparable in technical finesse and interpretive powers. Where the Dover, one of those younger groups enriching the field, radiated the thrill of discovery, the playing of the senior Emerson was steeped in experience.
This also seemed a different Emerson from the one that played two programs at Tanglewood last summer to launch the jubilee. There, in evenings of Haydn and Viennese composers, with Renee Fleming as soloist, the group had sounded more robust, more assertive. Perhaps South Mountain's more intimate ambiance and acoustics made a difference.
Yet Sunday's program was truly special. It opened with Mozart's Quartet No. 15, K. 421. The piece is in his stormiest key, D minor, and can become an exercise in storm and stress. Here, the unhurried performance let the harmonic and rhythmic motion carry the music along. Magically subdued, it issued a breath of melancholy, even tragedy. Schubert must have known this piece when he sat down to write his "Death and the Maiden" Quartet.
Shostakovich's Quartet No. 10, Opus 118, which followed, also invites heavy weather in performance. It, too, benefited from restraint. There was characteristic Shostakovich anger in the obsessive rhythms and grinding dissonances, but the music came across on a more humane scale, with even a sardonic smile at the finish.
On the perfect September afternoon, Dvorak's Opus 61 closed the program. It is healthy music, rich in melody, and it was played with generous light, grace and joy.
And the Emerson, the bearer of many awards, was off to a round of celebratory concerts.