The Phillips Collection opened its Sunday concert season yesterday afternoon with the Washington debut of a piano-and-strings ensemble called the Carnegie Trio. The three fine works performed -- by Beethoven, Copland and Brahms -- demonstrated to unmistakable satisfaction the special characteristics of phrasing and timbre that this particular musical form draws from such composers.

The piano trio is richer in sound than the normal string quartet -- with the violin, the cello and the upper range of the piano typically asserting the main melodic lines in bolder splashes, getting further support from sumptuous chords in the piano's bass.

But if its sound is often symphonic, the piano trio at its finest will draw a deftness and agility -- like an especially quick brush stroke in painting -- in the twist of phrase that is subtler than the more formal majesty one associates with symphonic development.

Yesterday's grandest expression of the possibilities of this chamber form came in Brahms' lengthy Trio in B Major, Op. 8. Don't let the early opus number fool you. The most sweeping melodic material in this masterpiece did come from his youth -- most of it was written in 1853, when he was 20. It was a bold flight of inspiration from the headiest, most passionate period of his writing.

It was not until years later, when Brahms was 57, that he decided that the trio was lacking in subtlety and rewrote it just about as completely as he could have without knocking out its identity altogether (only the demonic scherzo was preserved much as before, with just a new coda).

Yesterday's performance was one of those headlong enterprises that could have been nit-picked on some questions of polish and pitch. It was also on occasion also a bit rushed. But the work's thrust was caught with more assurance than in many a more careful version. Marc Silverman's piano playing was especially fine.

The Copland, in honor of the composer's 85th birthday (on Nov. 14), was his brief "dramatic character study" based on a Jewish folk theme that he heard in a performance of the play "The Dybbuk." It carried the tonal and harmonic characteristics of the piano trio to even starker, if less grandly scaled, extremes than the Brahms. Kim Scholes' cello playing caught this starkness memorably.

To open the concert, there was the gracious Beethoven C Minor Trio, Op. 1, No. 3. It came off with considerable brio.

The violinist was Christopher Collins Lee.