A diversity of approaches defined the 6th Annual D.C. Loft Jazz Festival that is to continue with one more performance this evening. The celebration at d.c. space was characterized by professionalism and maintained for the most part high artistic standards. The sponsoring organization, nonprofit District Curators, deserves credit for providing a forum for music that finds too few opportunities in the marketplace to present itself to its growing band of supporters.

Tenor Saxophonist Singh Neal led a quartet Saturday night that was notable for unorthodox interpretations of modern jazz standards as well as rewarding presentations of original materials. "Blue Monk," the Thelonious Monk classic that strips the blues bare, was identified in its introduction and in a concluding reprise of the theme, but all that lay between these signposts was exploration of virgin territory. John Kordalewski was at the piano, Ismail Numan on bass and Abu Sharif on drums. The stunning centerpiece of "Now's the Time," a duo of the leader and the drummer, was an exchange that had Sharif accompanying Neal and then a turnabout with the saxophone keeping time for Sharif's melodic inventions all over his drum kit.

A somewhat more straight-ahead outlook identified the evening's other group which was headed by alto saxophonist Fred Foss. Foss' initially pure tone and controlled expression became aggressive on the bridge of one extended number. Bassist James King pulled off several fine long-noted solos and the drumming of Winard Harper was consistently exciting. Larry Scott was in good form at the piano.

Tenor saxophonist Joe McFee, a player of enormous power who comes out of the '60s school of Albert Ayler, but an individualist in his own right, opened the program last night with Sharif, surely the area's premier "free" drummer. The 50-minute-long piece that launched their set seemed about nine parts free association to one part outline. Nevertheless, it was organized along lines of rising and falling intensity, had an inner swing and afforded moments of great beauty. McFee unleashed lion roars, mouse squeaks, big-toned ballad purity and hair-raising multiphonics. Sharif brewed percussive storms or he gently plied his traps according to the mood at hand.

The pianoless quartet of multi-reed player Byron Morris closed last night's program with a set of original tunes and several Ornette Coleman compositions. The format gave to the group an open sound that was enriched by the leader's good judgment of space and fine sense of balance. Morris' expressive and authoritative alto and soprano saxophones were well complemented by the impressively facile and original trumpet of 18-year-old Philip Harper.

Bassist Pepe Gonzales stood out nicely on a feature for his instrument, Coleman's "Face of the Bass." Once again the drums of Winard Harper laid down rhythmic patterns of singularly compelling designs. This is a new group to watch.