These days, it's no surprise to find unusual groupings of instruments--sometimes so odd you're hard pressed to call the resulting configuration a "band" at all. But even against this backdrop, the Ethnic Heritage Ensemble gets points for iconoclasm. Most improvising ensembles supply at least one of the following instruments to tie together the music's threads: bass, trap drums, piano, or even guitar. But the Ethnics' most frequent alignment finds them arranging saxophone and trombone in front of percussionist/leader Kahil El-Zabar's congas and earth drums--and letting it go at that. The horns are in the great hands of Joseph Bowie (the trombone-playing brother of trumpeter Lester who also fronts the neo-soul group Defunkt) and Edward Wilkerson (the hearty saxist and leader of the Eight Bold Souls), and they follow El-Zabar's trek through urban-slick landscapes to shamanistic hearths of darkness as well as light; a third of the way through an Ethnics set you no longer miss the missing instruments. How they get so much power and agility out of this stripped-down roadster of a band would seem to involve some shamanism as well. In any case, the results can be mesmerizing. (Incredibly, this concert marks their first appearance in their hometown since 1988; early arrival recommended.) Saturday, 8 PM, Hot House, 1569 N. Milwaukee; 235-2334.