Robert Plant has taken some slings and arrows recently for refusing to reunite with Led Zeppelin, but he says his restless need to try new things actually traces back to before he ever met Jimmy Page.

In fact, as Plant tells Sound Opinions, he'd worked with future Led Zeppelin bandmate John Bonham in an utterly uncompromising earlier group called the Band of Joy, and he learned something along the way.

"I was 19 years old then -- why would I ever compromise from then on?" Plant muses. So, he set about searching for "a colorful, exciting future," one that has taken him to a variety of musical places including -- but not limited -- to Led Zeppelin. As for "the nostalgia trip" that he says Baby Boomers sometimes indulge in, "I cut the cloth according to my needs. This, to me, is I think one of the most surprising, exciting and stimulating and also mostly heartfelt periods of my time as a singer."

Band of Joy performed in various configurations from 1965-68, and then again from 1977-83. Plant subsequently revived the band name in 2010 for touring purposes -- though obviously without Bonham, who passed in 1980. Plant has since been working with the Sensational Space Shifters, with whom he recorded 2014's 'Lullaby and ... the Ceaseless Roar.'

"The gray matter between your ears has gotta be stimulated," Plant says, "so how wonderful to have been in such great company for so many different parts of my life. A mass of people switch on to various parts of it, and it gives me the luxury of being able to do whatever I want to do."

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