The Quincy-Holmes Arts Festival let its long hair down last night, and the effect was miraculous. Twenty-nine musicians, two dancers, and a singer got together and put on the best (and practically the only) jazz concert at Harvard in a long, long time. Except for Liz Fillo, the singer, and for a drummer from the Divinity School, all the performers were undergraduates at Harvard or Radcliffe. But even if every one of them had been professional, they would have had no cause to be ashamed.

For the large and happy crowd which packed the roomy Quincy House dining hall, the evening's high point was the performance of the Blue Notes, a sextet which won first prize at the borschtbelt jazz festival at Grossinger's last year. The Blue Notes, four of whom are also in Gary Berger's band, played five jazz standards with astonishing competence; there arrangements were often original, their ensemble work sharp and clean. But individual solos are the test of small-group jazz, and the Blue Notes' soloists shone. Tenor Saxophonist Ben Friedman, a real crowd-pleaser, is technically master of his instrument. His best solo, on Thelonius Monk's Straight, No Chaser, was a honking, exuberant anthology of tenor sax styles, jumping from Johnny Hodges to Ornette Coleman to John Coltrane with deftness and humor. Friedman is strongly influenced by Coltrane, with a little Getz and "Fathead" Newman thrown in, and he has not yet found his own niche.

Ken Houk, the trumpet player, even looks a little like his unmistakable musical hero, Miles Davis. Houk's head is full of ideas, and although he sometimes appears to be thinking faster than he can blow, the emotional intensity of his playing is consistently high. The Blue Notes' trombonist, Sam Saltonstall, plays slowly and thoughtfully; there seem to be years of quiet cogitation behind each note. Rounded off by a hard-driving rhythm section (A1 Feeny, John Voigt and Billy Elgart), the Blue Notes are a swinging crew.

Equally interesting musically was the trio of pianist Pete Loeb. Loeb, who operates on the frontiers of, jazz, sounds a little like Thelonius Monk but is really his own man. He attacks a tune from all sides, alternating carefully spaced dissonances with tantalizing, full-handed chords. His bassist, John Voigt, provided a beautiful, sustained solo on Misty.

Liz Fillo, even with a fever and a stuffy nose, was her usual wonderful self. She can sing anything from the bouncy (A Little Jazz Bird) to the wistful (Something Cool) with real style.

Gary Berger's big band both opened and closed the concert. This fifteen piece ensemble has acquired a lot of polish in the past few months and is now as good as many professional bands. Their first set was their best: four tunes, all of them good, all of them played slickly and excitingly. Their closing session--two songs from West Side Story--wasn't bad, but those Johnny Richards arrangements, especially Maria, are a little too much for the band at this point. A jazz ballet by Ciji Ware and Dean Stolber, accompanied by Berger's band, closed the concert. The dancing was competent enough, but the choreography was no great shakes, and the performance was much too short for the dancers to really get started.