The program listing, "The Emerson String Quartet," at the Renwick Gallery's Grand Salon last evening was slightly misleading; actually, only one of the pieces performed was a string quartet.

A more accurate description would have been "The Emerson Quartet and Friends," for a Beethoven serenade and a song cycle by the British composer Peter Warlock (Philip Heseltine) placed the string players in a variety of chamber settings.

Violinist Philip Setzer and violist Lawrence Dutton joined flutist Sara Stern in a persuasive reading of Beethoven's effervescent Serenade in D Major, Op. 25. While the flute carries the bulk of the melodic invention, the score nonetheless contains generous lyrical passages for the strings. The trio hit its stride in the concluding allegro which dovetails gamboling themes in a fanciful manner.

For Warlock's song cycle "The Curlew," based on a text by W.B. Yeats, The Emerson Quartet became an ad hoc septet, with the addition of Stern, Kathleen Golding on English horn and tenor David Gordon. Static, drone-like harmonies, set off by a repeated haunting motive initiated by the English horn, painted a vivid aural picture in which the lowly curlew's cry triggers the poet's lovelorn state. Gordon's liquid phrasing and clear diction conveyed the intense musicality of Yeats' verse.

In Brahms' String Quartet No. l in C Minor, Op. 5l, No. l, the foursome displayed an ensemble unanimity readily adaptable to the sometimes pensive, sometimes turbulent, mood of the work. A flawless blend and ease of execution permitted an aggressive attack--most noticeable in the bowing of violinist Eugene Drucker and cellist David Finckel--that never disrupted the carefully-wrought linear development in the fast movements.