(Originally ran March 14)

Built to Spill sounded fine but seemed stuck in second gear early in its recent set at the State Theatre.

Then front man Doug Martsch announced a Brian Eno song and the band launched into “Third Uncle.”

The song’s propulsive rhythm lit a fire under the band and sent a surge of energy through the crowd. The three guitarists attacked their instruments, clawing at the strings by song’s end. The show began to soar.

Hearing a cover song is one of the joys of going to a concert. It’s a little bonus, a treat, and sometimes a reward for sitting through a so-so performance.

It also reveals something about the band, especially when the chosen tune is something off the group’s beaten path.

Covers were practically a given for 1980s college-radio acts. R.E.M. would remake Iggy Pop, Lou Gramm or Henry Mancini. The Replacements would try anything they could think of, depending on how drunk they were.

No Meat Puppets show was complete without a bludgeoning of Foghat’s version of “I Just Want to Make Love to You.” The Monkees’ “What Am I Doing Hanging ‘Round” got a surprisingly faithful reading by Dead Milkmen. Camper Van Beethoven would wig out on Pink Floyd’s “Interstellar Overdrive.”

Sometimes a cover reveals a lot about the audience, as in who likes it, who hates it and who doesn’t recognize it. “It’s Aerosmith!” I shouted to some younger and noticeably unimpressed friends while R.E.M. blazed through “Toys in the Attic” in 1985.

In 2002 it was Sleater-Kinney encoring with Bruce Springsteen’s “Promised Land” - I was one of about three in the crowd singing along.

Natalie Merchant’s version of Cheap Trick’s “Surrender” at a 1999 show is the only evidence I’ve encountered that she has a sense of humor.

And for all the times you’ve heard someone yell “Free Bird!” during a show, have you ever heard anyone cover it?