By this sesquicentennial year's end, what string ensemble will not have given us a surfeit of Brahms chamber music? Last night was the turn of the Emerson String Quartet, at the Renwick Gallery, in a concert that will be repeated tonight and tomorrow night.

Their performance came the closest yet to matching the lofty standards of Brahms-playing set this year by the Juilliard Quartet at the Library of Congress.

This young group shares many of the qualities of the more senior and celebrated Juilliard group--tonal splendor and power and an unerring sense of rhythm and momentum. They sweepingly projected the craggy grandeur of the F minor Piano Quintet, while the more reflective moments were intense in other sorts of ways.

The Emerson's precision with attacks and releases especially suggested the Juilliard. And the coda that ends the quintet sailed away with cyclonic force.

The pianist was Lambert Orkis, the National Symphony's new principal keyboard player, who was splendid. This reviewer has heard this work by three different groups in the last few weeks, and this performance was by far the finest.

Earlier came Haydn's D major Quartet, Op. 76, No. 5. There are few Haydn compositions that radiate more grandly the sense of well being and humanity of his mature years.

The Emerson's performance caught that feeling memorably--especially in the almost Elysian calm of the slow movement, and the underlying vitality never slacked. Once again the Emerson's tonal amplitude was superb.

Coming in between was a nice little interlude, the brief and endearing "Lullaby for String Quartet" that George Gershwin wrote in his early years. It is a pleasing mix of the spirit of the blues with the formality of the salon. The performance was lovely.