PITTSFIELD — Remember, the composition was premiered just a few months after Stalin's death, violinist Philip Setzer told the audience.

The Emerson String Quartet concluded its concert Sunday with Shostakovich's Quartet No. 5, which in turn concluded the South Mountain season. Even without the Stalinist history, the fiercely played music told the story. This 1951 work - angry, grieving and sardonic by turns - is one of the many that Shostakovich composed but could not have performed during the repression under Stalin. "Tombstones" for Stalin's victims, Shostakovich is supposed to have called his symphonies. Apt for the quartets as well.

The Emerson is 43 years old, and violinists Setzer and Eugene Drucker have been with it the whole time. Its age seemed to be showing in the first two works on the program, Mozart's Quartet, K. 575, and Dvorak's Quartet, Opus 51 (No. 10). The playing was clean and focused enough. It was a little too clean and focused, in fact, lacking the freshness that breathes life into music.

This was particularly evident in the Mozart quartet. Every time cellist Paul Watkins had the lead, the music sparked into life; he was especially eloquent in the aria-like andante movement. Elsewhere, Mozart seemed plain-spoken in the diligent traversal of notes.

Dvorak's Opus 51 quartet is folksy, outdoorsy music, redolent of sun, breezes and fields. The performance, though also assured, remained firmly indoors on the overcast afternoon. It was all very clear and correct. Call it sensuous appeal that was missing.

The Emerson, which is rounded out by violist Lawrence Dutton, has a special kinship with Shostakovich. Besides recording his cycle of 15 quartets, it tours a theatrical production, "Shostakovich and the Black Monk: a Russian Fantasy." (Another Emerson production, Andre Previn's "Penelope," misfired at its Tanglewood premiere last summer.)

At South Mountain, the ensemble seemed to be saving its energy for Shostakovich. Setzer's point in his brief talk was that Shostakovich was in official disgrace for much of his life while Stalin was alive, and only the easing of restrictions after his death made performance of such works as the fifth quartet possible.

The music screamed in anguish. It grieved in an unbroken hush. It turned a trivial waltz tune into a parody giving way to a descent into silence. The three movements flowed into one another amid such characteristic Shostakovich effects as ostinatos, piercing dissonances and mountainous buildups of sound.               

The performance evoked pure tragedy, which made the audience's clamorous standing ovation seem especially incongruous. The four players briefly conferred onstage and decided against an encore. Right decision. Why destroy what you have created?