Lots of radio stations bring musicians into the studio for live-on-air promotions, and some of them even issue CD compilations documenting some of those performances. But L.A.'s KCRW, which is currently on its third volume of Rare On Air, enjoys probably the highest-profile recorded legacy: The artists on Volume 3 include everyone from current chart-toppers (The Wallflowers, Fiona Apple) to hipster buzz bands (Ben Folds Five, Guided By Voices, Stereolab) to, well, James Taylor. And though most of the songs are merely drowsy variations on studio tracks you've heard before, there are impressive moments throughout: Fiona Apple's "Never Is A Promise" is impressively elegant and languid; Remy Zero's "Twister" is nicely reconstructed as a gentle acoustic ballad; and songs by Ben Folds Five, Booth and the Bad Angel, and Me'Shell NdegeOcello all benefit from classy arrangements. A few tracks don't translate well in the live-in-the-studio setting (Guided By Voices' "The Official Ironmen Rally Song," for one), while Cowboy Junkies' "State Trooper" doesn't do anything the original version didn't. But Rare On Air has mostly fine performances to match the big names.