When the Thorns cover the Jayhawks’ crowd-pleaser “Blue” early into the trio’s self-titled debut, the purpose of this project suddenly becomes clear. Matthew Sweet, Pete Droge and Shawn Mullins must have formed this second-tier version of the Traveling Wilburys to create melodies like the ones Mark Olson and Gary Louris used to make. They don’t quite pull it off (who does?), but they come close. These semi-disappeared songwriters hooked up not only to sing but also to write together, and the result is an album about the warm harmonies three talented voices can produce. The songwriting has some high points, but only a handful of songs are as memorable as the vocals themselves; experiments such as “Thorns” (the inspiration for the band’s name) and the depressive “No Blue Sky” work the best. The rest of the tunes are gorgeous, but after a few minutes, they’re really hard to remember.