'Troubadours' made the Earth move

It’s only rock ‘n’ roll and I liked it. The new documentary “Troubadours” remembers the thoughtful side in a bipolar era for music. In the early 1970s, you could let your freak flag fly with the Who’s smashed guitar theatrics or Led Zeppelin’s heavy bass grooves. Or, you could unplug and hear lyrics from the singer-songwriters who gave voice to the emotion of a generation left spent by the sociopolitical upheavals of the 1960s.