A preview of Jamaica's Reggae Sunsplash '86, set for August in Montego Bay, was held at the Convention Center Saturday night. Needless to say, the indoor location was hardly ideal. Virtually everyone in the crowd stood for the entire three-hour show, many of them atop the hall's vinyl chairs, either dancing to the music's persuasive rhythms or trying to see beyond the crowd to the performers on stage.

There was little fault with the music, however. Leroy Sibbles, best known as the lead singer of the Heptones, opened with a charismatic performance backed by the Soul Syndicate, a solid and versatile band that provided much of the evening's rhythmic momentum. Sibbles' handsome voice and easygoing charm drew the crowd into the rhythms of each song, whether it was a carefree party tune or a near-spiritual version of Bob Dylan's "I Shall Be Released."

The Mighty Diamonds, a veteran trio whose light harmonies recall American soul music, sustained the dance groove until Judy Mowatt arrived with her songs of affirmation and hope. A member of Bob Marley's vocal group, the I-Threes, Mowatt was never more compelling than when singing Marley's words, her voice growing more radiant and purposeful with each verse.

Black Uhuru concluded the show by nearly exhausting the crowd with its high-energy exhortations. As on a previous visit to town, the group covered a variety of its own material but saved something special for last: an impassioned and extended version of Little Steven Van Zandt's antiapartheid anthem "Solidarity."