Pitched between the dancefloor and the chill-out room but definitely leaning toward the latter, Machine Drum’s second album, 2002′s Urban Biology, moves away from the IDM leanings of 2001′s Now You Know into an artsier, trippier sound not far removed from DJ Spooky’s turntablism. These 15 pieces are built on samples and found sound tapes, not breakbeats, but there’s a similarly musique concrète feel to the way tracks like “Cream Soda Part 1″ and “Urban Biology” mix heavily processed ambient location recordings and wiggly synth lines, or the way the six-minute “Countchocula” conflates cool, vibey keyboards with a vocal sample that sounds like a single line by some unknown MC broken down into its component syllables and shuffled around according to pitch and melody, not meaning. At nearly 72 minutes, there are a few lesser tracks, and even a couple of the good ideas go on a minute or two longer than they should, particularly the nearly nine-minute dream-pop trifle “Floss.” Overall, however, Urban Biology builds on the better ideas of Now You Know and takes them into even more interesting new directions. – Stewart Mason