Jazz and audiences were alternately absent from most of the weekend's Kool Jazz Festival, but just enough of both made Washington's second edition of the annual event worthwhile.

The Kool Jazz Festival sponsored by the cigarette company, is probably the only concert in America that comes with a warning from the Surgeon General. Friday night's turnout at the Capital Centre indicated that most people took the ". . . hazardous to your health" tag to heart. Only 3,000 people huddled at the far end of the cavernous arena to hear Joe Tex, Tavares, and Rufus featuring Chaka Khan. All three artists had one thing in common - none played jazz.

The Kool Jazz Festival, sponsored by the cigarette Newport Jazz Festival. Newport mogul George Wein handles both. In 1972, Wein decided to put big-name rhythm 'n' blues acts - including War. Gladys Flack - into Shea and Yankee Stadiums in New York. The justification was: blues is a subset of jazz, rhythm 'n' blues is a subset of blues, so these acts can safely be called "jazz."

These acts also were called "money," and that concept has remained. This year's 13-city Kool Jazz Festival tour packed fans into such intimate jazz clubs as Houston's Astrodome and the Oakland Coliseum. Two night of this "jazz" at $9 or so a pop makes a lot of cents.

The misnomer does not stop the performers from doing what they do best. Joe Tex opened the two-night stand Friday by Slithering through a set of tunes that included the well -known "I Gotcha." Tavares then exhibited some flashy choreography throughout hits like "It Only Takes a Minute," "Heaven Must Be Missing an Angel" and "She's Gone."

Rufus featuring Chaka khan bore the evening's closest resemblance to jazz. The influence of bona fide jazz pianist McCoy Tyner, most recogizable in "Egyptian Son," and the mass appeal approach to melodies like "Hollywood," added variety and musical significance to the ban's work.

Saturday night, over 18,000 customers got to hear fine sounds. the Floaters challenged Tavares for "Best Chorus Line" honors and had the crowd dancing to their native Motown boogie in "Float On." The Bar kays were the biggest surprise of the weekend. Completely revamped sinde the 1967 instrumental hit "Soul Finger" and the plane crash that killed three original band members and singer Otlis Redding, the Bar Kays kept up a driving but controlled rhythm that left no one sitting still.

Vibraphonist Roy Ayers, a Washington-area favorite who seems to put out a new album every three weeks, coudn't keep up the pace. Formerly a Milt Jackson prototype, Ayer's playing has gotten more strident lately and he now sings as much as he plays. "Searchin" almost got the audience back in gear and saxophonist Justo Almerio played with a vengeance but the Bar kays were a tough act to follow.

Natalie Cole closed the Festival but the crowd closed her first. Opening with a blistering "Sophisticated Lady," Cole followed with two slow bakkads, both prefaced with languid spoken introductions. Great for Las Vegas, fatal at the Capital Centre. People headed for the exits in droves despite a powerful performace that displayed Cole's agile voice and ever-increasing range.