Phillips Collection concerts are frequently a forum for introducing artists to the area, but Sunday's concert reached much farther afield than usual to present the Kreuzberger String Quartet from Berlin in a promising Washington debut. The group, formed in 1970, has won several European prizes, including a first at the International Competition in Geneva in 1974. Currently on its first American tour, the quartet performed in the United States once before, in 1976, when it was invited to Yale University.

The four musicians have developed a well-disciplined ensemble and a warm tone, notable for its depth and fine blend. Their manner of playing possesses a deliberateness that imbues the music with a satisfying solidity. Sometimes, however -- as in the opening Hadyn Quartet, Op. 33, No. 2 -- their style edges toward heaviness. They were at their best in Stravinsky's Concertino for String Quartet, handling its asymmetrical rhythms with ease and reveling in its dense, highly concentrated writing.

In the closing Beethoven Quartet, Op. 59, No. 3, more of first violinist Wilfried Ru ssmann's occasional sound and pitch inconsistencies cropped up and cellist Peter Gerschitz took a little time to develop the presence needed. Nonetheless, the interpretation gradually intensified, culminating in a final movement of almost perilous speed. As these gifted players, all in their thirties, cultivate a more expansive attitude that is almost certain to come with time, the many passages of strength should be complemented by equal amounts of beauty.