Which Bud Shank is the real Bud Shank? When he first made his reputation back in the 1950s, he was among the coolest of cool jazz players: his alto sax had a pure, limpid sound and his phrases often hesitated behind the best, suggesting a lighter, less intense Art Pepper with something of Lee Konitz's detachment. In those days Shank also played flute in duets with oboist Bob Cooper, a combination that was about as west coast as you could get. But in more aggressive contexts his alto would sing out with a full sound, and he sometimes played a swaggering baritone too. His multiwoodwind versatility led him to disappear into the obscurity of Hollywood studios for most of the last three decades. Now he's playing jazz full-time again, alto sax, in a robust, extroverted way that during intricate passages recalls Cannonball Adderley; yet at last year's jazz festival there was a taste of the old shy intimacy. Through it all, he's retained his fondness for melody and a highly refined technique, full of little flourishes and felicities of phrasing--maybe those matters, rather than matters of projection, are the ones closest to Bud Shank's heart. With Stu Katz (piano), Bob Bowman (bass), and Joel Spencer (drums), Tuesday through next Sunday, August 11, Joe Segal's Jazz Showcase, Blackstone Hotel, 636 S. Michigan; 427-4300.