by Jason BirchmeierFunkmaster Flex keeps his Mix Tape: 60 Minute of Funk going with Volume 4, which features mainly freestyles. Performers include some of the industries top rappers -- primarily New Yorkers like DMX and Ja Rule but also a few out-of-town surprises like Eminem and Ludacris -- most of whom freestyle over Flex's own productions. The plethora of exclusive productions sets Volume 4 apart from its predecessors, which were more straightforward mix albums comprised of previously released hits. As such, Volume 4 offers a lot of performances that cannot be found elsewhere, so fans of the featured rappers should take note. Newcomers are probably better served by earlier volumes, though, as the inclusions here aren't quite as astounding as the proven hits of before, nor is Flex's mixing, since he's more interested in showcasing his beatmaking here than his turntablism.