Every city worth its salt has plenty of terrific musicians working just under the typical concertgoer's radar, which only tends to pick up the big stars. Like many such players, tenor saxist Mark Colby spends most of his time teaching (at Elmhurst College and DePaul University), performing in public too rarely for my taste. His music reflects an appreciation for the ageless virtues exemplified by Stan Getz: a hooded tone, velvety in the lower register and diamond hard in the upper; pinpoint technique, so that his phrases crackle and pop; and a love of melodies that verge on the voluptuous. Though Getz has clearly influenced at least one other Chicago tenorist--Greg Fishman, of the group Two for Brazil--Colby seems to have arrived at an unspoken agreement with his colleague, ceding to Fishman the legacy of Getz's bossa nova period and reserving for himself the material that characterized most of the rest of Getz's career, from wistful ballads to speedy blues tunes and adventurous jazz compositions. It won't change your life to hear Colby apply his considerable talent to an especially tricky (and rewarding) passage, or develop a shard of an idea into a memorable statement; his solos don't break new ground. But he tills his familiar plot with consummate skill, and manages to make sturdy, meaningful music every time out. Players like Colby provide a necessary reminder that jazz doesn't have to destroy its past to remain fresh--the process of improvisation, in the right hands, ensures the music's continued vitality. Colby's previous downtown appearance, at the Jazz Showcase during the 2001 Marshall Vente Jazz Festival, has yielded the just-released live album Tenor Reference (Hallway); he returns to the Showcase to celebrate its release as part of this weekend's Hallway Records Jazz Festival (which also features a CD-release party Saturday night for violinist Diane Delin's impressive Talking Stick). Sunday, February 17, 4 PM, Jazz Showcase, 59 W. Grand; 312-670-2473.