Code 4109 is the first "proper" mix album from one of trip-hop's reigning DJ masters -- his two previous efforts, Back in the Base and Holonic, were restricted to, respectively, material from the Ninja Tune label and his own work. It's also an excellent compilation, never sacrificing the trademarked earthy grooves on the altar of experimentalism. None of the tracks are obvious inclusions -- except for a few of Krush's own productions -- and the material that is here has obviously been worked on heavily while on the turntables; Krush transforms, tweak scratches, and attempts all manner of effects on the tracks. From the vicious detuned monster "Back to the Essence" (by Gravity) near the beginning, he spins material from those with similar aesthetics (DJ Cam, the 45 King, Jazzanova) and uses more eccentric inclusions (John Klemmer, Beats International, a Bulgarian choir, Japanese jazz artist Minuro Muraoka) as layering for the stoned beats and haunted basslines on the primary tracks. More so than most of DJ Krush's material, Code 4109 progresses through different sounds and styles with panache and dexterity.