Always awash in great tenor men, bassists, and pianists, Chicago has never really been much of a jazz trumpet town (at least not since Louis Armstrong departed in the 20s); so calling Orbert Davis the city's hottest hornman might seem a minor compliment. Don't let the lack of competition fool you, though: Davis would attract attention in Gabriel's shadow. He fits into a trumpet lineage that celebrates musical intellect--a lineage that includes the frequently overlooked Randy Brecker and the late Woody Shaw and extends back to Clifford Brown in the 50s. Davis brings a listener to seat's edge through the sheer intelligence of his improvisations. It doesn't hurt that Davis (like his is predecessors) possesses a spine-tingling command of the instrument, which underlies, informs, and validates his highly concentrated solo inventions; indeed, there is no doubt of his ability to grab the ear with such traditional trumpeters' tricks as high-note blasts, soaring glissando swoops, or rapid-fire articulation. But such devices don't really suit his purpose. Neither does the often empty swagger of a Freddie Hubbard, for which Davis substitutes the crisp logic of the impeccably sculpted line; when he solos, you can't take your ears off him. Davis spends much of his time in the commercial studios, but this new quartet leads one to hope for a jazz album in the not-too-distant future--and not only for the fun of finding a title (In Orbert, The Geosynchronous Orbert, and Orberting come immediately to mind). Saturday, 8 PM, Green Mill, 4802 N. Broadway; 878-5552.