Local roots-music fans know all about KC Groves. A longtime Lyons resident, she's one-fourth of Uncle Earl, a combo that's played lots of gigs and festivals in these parts and contributed a song to the 2005 Colorado Bluegrass Music Society compilation. Now, however, the outfit is taking a giant step toward national prominence with Waterloo, Tennessee, a new disc on Rounder Records produced by none other than founding Led Zeppelin member John Paul Jones. On the surface, and below it, this seems like an odd combination. But Jones has played music inspired by folk and acoustic traditions before (spun Led Zeppelin III lately?), and he's smart enough to let Groves and cohorts Kristin Andreassen, Rayna Gellert and Abigail Washburn be themselves. The CD's sound is pure, clear and uncluttered, whether the band is ripping through rave-ups like "Wish I Had My Time Again" or getting dark on the deeply felt dirge "My Epitaph." At moments like these, it's hard to imagination a more compatible couple than KC and Mr. Jones.