Harper and Johnson capture that retro vibe

If the Hollywood Bowl occasionally seemed engulfed in a time bubble from the ‘60s and ‘70s on Monday, it wasn’t just the many echoes of the era in the music of co-headliners Ben Harper and Jack Johnson.

There were certainly plenty of those, with Harper evoking at times Eric Clapton, Bob Dylan, Cat Stevens and Marvin Gaye, and Johnson recalling Jimmy Buffett and James Taylor. Both also dipped especially deep into the reggae well of Bob Marley.

But just as significantly retro was that these two, who have never been pop-radio favorites, were able to sell out the Hollywood Bowl in the first place. That’s an echo of ‘70s-style career building at its best, when artists gained intensely loyal followings through touring and artistic integrity.

It’s not unique even today -- Dave Matthews, Phish and a host of jam-related bands rely on the same M.O. It’s noteworthy enough, though, to compensate for a few other concerns.

Santa Barbara-based surfing champ-turned-crooner Johnson’s main shortcoming is energy. But his laid-back manner also had its appeal during his set. There’s no pretense in his simple-man persona or his stripped-down acoustic guitar, bass and drums lineup. And he possesses an attractive, understated voice and gift for pleasing melody and quasi-reggae rhythms.

What also came through was Johnson as beachcomber philosopher, whose songs ask us to slow down and pay attention to real values rather than material needs. It’s hard to feel bad about that.

Claremont-raised Harper, with five studio albums under his belt, was a lot more forward with his music, following Johnson with a blend of classic rock, ‘70s funk, blues, reggae (two spot-on re-creations of Marley’s early-’70s sound) and gospel.

In “With My Own Two Hands” and “Blessed to Be a Witness” -- two highlights from his recent “Diamonds on the Inside” album -- he translates personal spiritual beliefs in a Marley-like manner. And in the encore “Like a King,” calling on the spirit of the Rev. Martin Luther King Jr., the bluesy fire with which he played his lap-slide guitar was a manifestation of a belief that music can change the world. How ‘60s is that?