by Stephen Thomas Erlewine Trimming away some of the overt Afro-Cuban rhythms that distinguished Black Fire, Andrew Hill turned in a dense, cerebral set of adventurous post-bop on his second Blue Note session, Smoke Stack. Comprised entirely of original Hill compositions, Smoke Stack is in the middle ground between hard bop and free jazz -- it isn't as loose and dissonant as free, but with its long, winding modal improvisations and hazy song structures, it's a lot less accessible than bop. It also isn't as successful as Black Fire, which worked similar territory with edgier results. Part of the problem is that Hill simply meanders throughout most of Smoke Stack, wandering off into quietly discordant sections that turn in on themselves. It's subdued music that requires concentration, but doesn't necessarily reward such effort. Even with its faults, Smoke Stack is far from an unworthy record -- Hill's insular, intellectual style may be occasionally frustrating, but his playing is frequently provocative and challenging, and his backing group of Richard Davis (bass), Eddie Khan (bass), and Roy Haynes (drums) offer sympathetic support. However, it's an album that promises more than it delivers.