Music doesn't get much more basic than this: the Tuareg group Ensemble Tartit combine call-and-response vocals, syncopated hand claps, rudimentary rhythms tapped out on the tinde (a grain-grinding mortar that becomes an instrument when fitted with a piece of goatskin), and three- or four-note licks played on a one-string fiddle called the imzad, and the cool, mesmerizing sounds that result evoke the endlessly rolling dunes of the Sahara. The Tuareg, or Kel Tamashek, are a nomadic people who've drifted through Algeria, Libya, Mali, Niger, and Burkina Faso for centuries but began facing systematic oppression in the late 20th century. They've attempted to fight back several times over the last four decades, most recently in the early 90s, with little success; a 1994 clampdown by Mali's military led to a wide dispersal of the population into refugee camps--in one of which Ensemble Tartit was formed in the late 90s. This music originally accompanied rituals and celebrations--Ramadan, weddings, births, even divorces--but Tartit play it to preserve and publicize its cultural identity, and along with the progressive group Tinariwen the ensemble has made the world more aware of the plight of the Tuareg. The core of the group is five women who sing and play tinde and imzad; on Tartit's sole recording, Ichichila (Network, 2000), they get spare support on electric guitar and a traditional lute called the tehardent. At times the music recalls the bluesy work of Malian great Ali Farka Toure, but the ensemble strips the sound way down, so that every subtle vocal tremor carries the impact of a cannonball. This gig marks the group's Chicago debut. Friday, April 11, 8 PM, Old Town School of Folk Music, 4544 N. Lincoln; 773-728-6000.