Robert Plant and Alison Krauss' Raising Sand

When the concept is "two adults singing," the voices had better be damn good. Krauss delivers her usual plain/pretty soprano, but it's Plant that's the revelation, toning down his Whole Lotta Love falsetto to match her warmth and delicacy. It's a lovely pairing, especially on the Everly Brothers' Gone Gone Gone (Done Moved On).

Rating: A-