Kaarl and Margaret Kohn in their recital of four-hand piano music paid very generous homage to the composer, Franz Schubert, who has made that genre peculiarly his own. Mores than half of last Wednesday's program was devoted to his music, notably to the Variations, Op. 35, and to the grand Duo, Op. 140.

To convey the immense sweep of the latter work and yet do justice to episodes of intimate chamber music is the formidable task facing the performers. They must possess not only virtuosity, but a delicate rapport in ensemble; not only forceful rhythmic drives, but the courage (and control) to bring a lengthy phrase to a hushed and protracted close. Mr. and Mrs. kohn seemed aware of the immensity of their task. Much of the playing was brilliant as well as subtle. Yet on the whole, the performances of the Schubert works left too many problems unsolved or only half-heartedly assaulted.

I thought the most glaring fault was the lack of any dynamic of tonal norm whereby the long forte passages could be saved from conveying an impression of bombast and anti-climax. On the other hand the faith in Schubert's lyricism, which undoubtedly underlay the performance, was not pushed so far as to infuse each phrase, and as a result even ardent Schubert lovers would find it hard to apply to this performance Schumann's epithet of "heavenly length."

The shorter works which filled out the program, a sonata by Johann Christian Bach, and Hinde mith's Sonate (1938) were delightful and superbly performed. At first hearing, the Hindemith revealed a compression of structure in which a few, simple ideas receives coherent, sometimes fascinating development, though within quite limited terms.

The short Bach sonata was tossed off at the beginning of the program almost in the spirit of a game, and its success was total. I cannot imagine a more perfect agreement on the spirit of a work and the gestures for its expression than the Kohns' attained in this piece.

Mr. kohn, a teaching fellow in Music, who has thus auspiciously introduced himself as a performer, will he seen as a composer at the end of this month when the glee Club introduces his new cantata.