Harvey Phillips is a remarkable musician who has chosen an even more remarkable instrument as his medium. Yesterday afternoon, in the first tuba recital in the history of the Library of Congress, he demonstrated that an amazing variety of sounds--including some that are exquisitely musical--can be drawn from a long, conical piece of brass plumbing.

Phillips performs with a superb sense of phrasing, well-varied expressive nuance, and the instinctive rapport of a true chamber musician--virtues that were particularly evident when he played his tuba arrangement of the Brahms Trio for horn. If his instrument were a flute, violin or cello, he might be as widely known as Rampal, Perlman or Rostropovich.

"Eight Random Thoughts" for unaccompanied tuba by the late Edward Sauter (cofounder of the Sauter-Finegan Jazz Orchestra) is a series of moody, melodious and often technically demanding exercises: arpeggios, octave leaps, and variations of dynamics, tonal color and pace. Phillips gave a virtuoso performance with total control of the instrument, clean articulation, precise intonation and rich tone. Then followed Richard Strauss' rather uneventful Sonata in E-flat, performed by pianist Doris Pridonoff Lehnert and violinist Oswald Lehnert, who were Phillips' partners for the second half of the program.

This was the more interesting segment, with Charles Eakin's tersely lyric and very expressive Introduction and Allegro, composed this year for these three performers, and the Brahms Trio, a work that Phillips has enrolled decisively in the repertoire of his instrument. The Brahms was by far the greatest music on the program, and it received a performance fully attuned to its greatness. The Lehnert Duo played with more vitality than in the Strauss and Phillips negotiated the fast passages with elephantine agility, the soulful slow sections with golden tone.