Back to Back captures the instrumental aspect of the ’67 Stax-Volt European tour (“Volt” is the name of Stax’s subsidiary label). Immediately apparent is that the live versions of these songs are played much faster than the recorded ones. Exuberant? Definitely! These folks were racing across unfamiliar cultures and landscapes, reimagining their place in this world, looking down at the clouds for the first time. The pace was faster because their lives were — quickly — getting so much larger. In these recordings, you can hear all of that emotional exhilaration, all of that savoring of personal respect, that thrill of the new. Many of these songs were several years old, but they shine on Back to Back like they’re being performed for the first time. Over and over, you hear the musicians throwing in something extra, curlicues and tangents that express their excitement.