It is an amazing fact that a concert of the relatively obscure violincello sonatas of Beethoven could pack Sanders Theater, but pack it did Wednesday night. An audience so large that many were standing along the back walls heard Bruce Simonds, dean of the Yale Music School, and George Brown, a member of that school's faculty, play three of Beethoven's five sonatas for piano and cello and 12 Variations on a Theme by Mozart.

It is unfortunate in view of the crowd that the concert, sponsored by the Harvard Department of Music, was not better. Mr. Brown, playing the cello, rarely matched the musicianship of his partner. The Piano part was played by Mr. Simonds in a fashion that left little to be desired. Not only was it technically excellent, but there was enough personality and feeling injected into it to make it brilliant.

The cello, on the other hand, frequently could not be heard. On a few rare occasions it could be heard all so much. During the rondo movement of the Sonata G minor and the last movement of the Sonata in A major it went distinctly flat. The general impression created was that Mr. Brown was nowhere near up to the technical standards that the piano was setting. He played too quietly and lacked the precise timing necessary in the fast movements.

In all fairness it cannot be said, however, that the concert was not enjoyable. There were several moments of great beauty, especially in the slow moments of the sonatas and in the eleventh variation on the Mozart theme. Mr. Brown succeeded in putting a great deal of feeling into his playing at these times. All the singing qualities of the instrument that were missing in other movements appeared here.

Beethoven write very few sonatas for the piano and cello, probably because it is so difficult to coordinate the widely varying sounds of these instruments. But the sonatas nevertheless did succeed in mastering the difficulties of composition imposed by the two instruments.

The great difficulty with the actual performance of these works was that the men frequently destroyed this masterly. Beethoven made the cello part the more important occasionally, made the two parts equal the rest of the time, and almost never put the piano into prominence. Unfortunately, Wednesday night the cello part was only occasionally equal to that of the piano and frequently less prominent.