How’s this for trendy indie-rock cred? Saddle Creek artists Son, Ambulance debuted on an EP split with Omaha labelmates Bright Eyes. Faithful to its popular hometown record company, Son has stuck around for two subsequent albums (2001’s gauzy Euphemystic and this autumn’s Key). The band, a revolving group of musicians, has at its center Joe Knapp, whose obsession with lyrics may explain why the new collection took three years to compile. Knapp’s piano-man approach, wavering falsetto and storyteller style have earned him justifiable comparisons to Ben Folds. Generally not as perky (or quirky) as Folds, Knapp has been accused by some of creating yawn rock. His childlike playfulness — exhibited on songs such as “Chlorophyll” — nonetheless generate smiles aplenty.