Gabriel fans hoping for a follow-up to 2002's Up will have to keep waiting. Big Blue Ball is neither new nor is it strictly Gabriel, although the pioneering art rocker's aesthetic stamp (and, on four songs, his voice) is all over this global-music mosaic. In the early Nineties, Gabriel staged a series of jam sessions at his Real World Studios in the English countryside, where musicians ranging from Sinéad O'Connor to Living Colour guitarist Vernon Reid to soukous legend Papa Wemba sang or played over multilayered dub and rock, swirling electronics, pan-African polyrhythms, Spanish guitar, Asian percussion, snaky Egyptian orchestration and more. After 17 years of meticulous production, the result of this modern-traditional fusion, though ambitious, is a bit uneven. Individually, tracks like Malagasy singer Rossy's mash-up of rap, electronics, funk and jazz on "Jijy" or Hungarian singer Márta Sebestyén's minimalist beauty, "Rivers," can be mesmerizing. But old-style prog-rock pretentiousness sometimes rears its head, such as on the Joseph Arthur-sung throwback "Altus Silva," which sounds as though it arrived straight from the Court of the Crimson King.