Fans of folk–rock rejoice! Mumford and Sons is back with another banjo–twanging album. “Babel,” their sophomore effort, is a poignant continuation of 2009's “Sigh No More.” As “Whispers in the Dark” and “I Will Wait” demonstrate, Mumford kept their familiar folksy sound, but now it’s infused with a swashbuckling energy, while album low points “Broken Crown” and “Reminder” are quiet, understated and almost boring in comparison. The openers reverberate with an attractive intensity, but the slower songs tend to fall flat. Veteran fans should add this album to their collection, but newer fans should save their money for “Sigh No More” instead.