There has been much huffing and puffing about how neo-romanticism is the wave of the musical future, but less evidence that the wave is gaining power. Thus John Harbison's bracing new Piano Quintet was all the more welcome when played by the Meliora String Quartet with pianist Robert Freeman yesterday at the University of Maryland.

It is a dark, moody piece, reminiscent of Barto'k but of great terseness and eloquence on its own. There are five movements, but the desperate striving of the lengthy opening and the desolation of the finale dominate it.

Harbison dedicated the Quintet "to Georgia O'Keeffe . . . and friends of the Santa Fe Chamber Festival," of which the artist is a long-time sponsor. Harbison draws a parallel between his quintet and the "unfilled parts of her canvasses, the open space, the pleasure of leaving something out." He later links the work's mood "to difficult circumstances under which it was composed," without elaborating.

The inner movements are described as "character pieces": the second whimsical, the third brooding, the fourth almost brutal, making its juxtaposition with the concluding elegy, with its wailing cries high in the violins, all the more poignant.

And throughout, the work is propelled forward by incessant rhythms, mainly in the piano. That piano was played superbly by Freeman, who is also director of the Eastman School of Music. The Meliora Quartet consists of four players in their mid-twenties who actually applied at the Eastman as a quartet, where they have become prote'ge's of the Cleveland Quartet.

They are not yet as polished as their mentors, but they play with a high-risk intensity that was shattering in the Harbison and that produced one of the most dramatic performances of Debussy's Quartet I have heard in years.

Its slow movement, especially, with its very soft playing, was marvelous. An unexpected incident proved their mettle. The score of the first violinist, Ian Swensen, fell to the floor in mid-movement, and for some time he continued playing from memory, without bothering to pick it up.