By Stephen Brookes • The Washington Post • September 15, 2011

Baltimore’s Mobtown Modern Music Series has presented some of the area’s most provocative new-music concerts for several years now, and to judge by this season’s packed opening concert Wednesday at that city’s 2640 Space — the complete string quartets of Iannis Xenakis, played by the JACK Quartet — it’s becoming downright essential. Xenakis is, of course, one of the great musical minds of the late 20th century, but his quartets languished in semi-obscurity until recently, when the young JACK players took them up. Their high-octane performances of these works are absolutely sensational — and have become an event in every sense.

Iannis XenakisXenakis isn’t for everyone, of course. Forget the intimate poetics of much of the quartet genre; these four quartets are almost physical in their violence and undiluted power, and owe more to the natural world than to the evanescent fluctuations of the psyche. Rooted in mathematics and game theory, they explore sound in brilliantly innovative (if sometimes almost overpowering) ways.

But the JACK players brought Xenakis’s quartets into perfect focus, alternating the early, relatively accessible quartets with the weightier and more difficult works written toward the end of the composer’s life. There’s a kind of life-and-death urgency about the late quartets; “Tetora,” from 1990, packs sound so densely that it becomes almost solid, moving forward with the elemental implacability of tectonic plates. “Ergma,” written four years later, is even more brutal and uncompromising, using sustained dissonances to batter its way into a new musical universe. Neither work is pretty. But both have the kind of savage beauty that comes with utter honesty. This is music written for keeps.

The quartet played both pieces fearlessly, but their virtuosity really shone in the two earlier quartets. “ST-4/1, 080262” was a vivid, brilliantly colored and hugely enjoyable work from 1956-62, but it was 1983’s “Tetras” that really stole the show. Almost symphonic in its range of sonorities and absolutely exhilarating from beginning to end, this may be one of the great quartets of the 20th century.