THE SIXTH-GRADERS, poised for action, could only wait as the tape recorder ground out the Citystep dance troupe's soundtrack at something like quarter speed. Their smiles remained as their poised-for-dance positions grew awkward. Every pair of eyes in Sanders Theater focused on the leg at the rear of the stage that was pointed straight up--and becoming too heavy for a tiny, grimacing dancer to bear. The kids needed to move, needed music, needed Jazz for Relief.

When the tape recorder started blaring, the eight Citystep dancers began their routine and captivated the 4th annual Jazz for Life concert's almost-full house. The Citysteppers earned the warmest reception of the night by moving easily from sweeping, elegant steps to a 1980s version of West Side Story choreography. The Jazz Band, the Opportunes Robespierre and nearly 100 other Harvard performers also contribute to the Jazz for Life effort.

ALL OF IT was difficult to resist, impossible to shrug off as another mini-version of a high falutin' charity gala. Formal dress was not required, and neither was false piety or sentiment. It was a come-as-you-are, come-to-be-entertained affair. By making their show a fast-moving, talent-packed one, the Jazz for Life organizers served the audience as well as Oxfam America and the Phillips Brooks House Homeless Committee, the evening's charity beneficiaries.

The performers were on their best behavior, doing one or two tunes with eagerness and then getting off the stage to keep the show moving forward. Few bothered to promote upcoming concerts and few preached that we were very special to turn out in such great numbers for a charity affair.

There were some technical glitches and the usual delays between groups, but helpful people filled the time with talk. Acting Harvard President and Jazz for Life host Henry Rosovsky smoothed the evening's snags. When the Citystep tape went wrong Rosovsky stepped onstage, presented the PBH bowl for public service and then fired off amusing anecdotes until the machine got fixed.

Also very impressive was the presence of alumni performers who came back to be part of a tradition started four years ago. Rex Dean '84, the founder of Jazz For Life, returned to sing, as did Paul Brusiloff '86 and the Cambridge-based, alumni-dominated vocal group Centerpiece. Saxophonist Don Braden '85-'88 interrupted his studies to tour with Wynton Marsalis and may never return to Harvard for a degree. He did, however, return to support Jazz For Life, playing both as featured soloist and as sideman.

ROSOVSKY CALLED jazz--"America's most important contribution to culture"--during his introductory remarks, but it soon became clear that although this was Jazz for Life, the music wasn't really jazz. The Jazz Band finished its set before everyone had made it to their seats and jazz-tinged versions of pop tunes--like Van Morrison's Moondance--were the night's standard fare.

Braden provided a friendly mini-lecture on the structure of jazz improvisation, but his words may have been lost given the number and variety of the performances. In any case, the high spirits and the impressive talent of the night, especially Fiona Anderson and Brian Williams, quieted the complaints of the purists.

The evening never degenerated into a self-conscious, self-congratulatory benefit of the sort Live Aid has taught us to expect. Even the finale, a Live-Aid-style chorus line, maintained the show's dignity. With a better song (the classic pop tune Lean On Me) and little jockeying for favorite microphones, the Jazz For Lifers put on a showcapper that closed an uplifting evening on an uplifting note.