I’m tempted to say that Dawkins & Co. represent the face of the A.A.C.M. today, but that would be misleading: the organization has always made room for music (like theirs) from within the tradition, as well as sounds on the frontier. Yet in this, the A.A.C.M.’s third generation, more Chicago members than ever before have staked out the middle ground, finding it a fertile medium for the sonic, structural, and improvisational exploration that remains the A.A.C.M. signature. And no group travels this territory better than New Horizons, a muscular, cohesive quintet that effectively counters the “neoclassic” elements rampant in modern jazz. While youngsters in the Marsalis mold have grown up (and continue) aping the hard-bop giants, the members of New Horizons long ago moved beyond first influences to push their music forward, and their experience reenergizes even conventional forms and idioms. Dawkins (who also leads the reed battalion Saxophonitis) has developed into a forceful soloist, doing justice to the meaty, swinging lines that seem genetically bred into Chicago saxists; he’s matched with the brash trumpet of Ameen Muhammed, while trombonist Steve Berry’s hard-won, almost diffident melodies provide an effective foil. The spirited bassist Yosef Ben Israel and the kaleidoscopic drummer Avreeayl Ra round out the group, which performs on the fourth program of A.A.C.M.’s seven-week autumn concert series. Friday, 9 PM, A.A.C.M., 7058 S. Chappel; 752-2212.