Beethoven's total output for cello and piano consists of five sonatas and three sets of variations on themes by Mozart and Handel. As part of the special chamber series at the Terrace Theater, cellist David Soyer and pianist Peter Serkin are playing this music in two programs. The first one Saturday night brought forth craggy strength from Soyer and compelling song from Serkin, one of the few pianists in memory able to turn the tough Terrace Theater piano into a sensitive, singing instrument.

Having played together frequently, Serkin and Soyer know each other's language intimately. Both bring a keen, inquiring intelligence to music, laying bare the structure of a work with immaculate clarity. They began with Beethoven's first essay for the piano-cello combination, the F-Major Sonata, Op. 5, No. 1. Delving into its innards, they exposed both its links with tradition and its vigorous hints of a radical future, in an interpretation at once lyrical and sinewy.

It is, in fact, the pull between these two qualities -- Serkin supplying an exquisitely refined touch and Soyer contributing a rock-like solidity -- that gives their ensemble playing its distinctive style. They gave a strong performance of the C-Major Sonata, Op. 102, No. 1, though it did not quite match the fervor and unity of approach in the initial sonata. The first of the two sets of variations on themes from Mozart's "The Magic Flute" proved a pleasant diversion before a charged rendition of the closing A-Major Sonata, Op. 69. The intensity level is almost certain to be equally high for the second program tomorrow at 7:30 p.m., an evening not to be missed.