Ever since the recording industry began marketing African music to Westerners, it's been disheartening to note how many acts have embraced glossy, high-tech production style, to the point where their music starts to resemble the overprocessed Anglo-American pop slop that sent so many listeners to the international music bins in the first place. It's not so much that African acts are filtering the grit out of their art to broaden its appeal to foreigners--on the contrary, it appears that the tendency for musicians to be attracted to studio slickness may simply be universal. Certainly the urge to modernize is understandable, and it would be condescending to insist that African musicians keep their music and recordings technologically "primitive." But one does miss the scrappy, spontaneous edge of earlier records, as surely in African music as in American rock and roll. Mahlathini and the Mahotella Queens offer a lesson in how African pop music can be modernized without blunting its bite. The fact that they've been performing since the mid-60s may give them a bedrock confidence others lack; at any rate, they've managed to assimilate synthesizers and other innovations without losing their essential edge. The contrast between Mahlathini's gravelly groan and the Queens' lilting high harmonies still makes for an exquisite textural balance, like whipped cream and nuts. Any discussion of contemporary South African township jive starts here, of course. Saturday, Equator Club, 4715 N. Broadway; 728-2411.