Back when the Twin Cities' hippest FM stations both played John Mayer and Dave Matthews to no end -- and few local bands, if any -- Walker Art Center staffers still pulled some of the coolest Minnesota musicmakers out of the radio gutter to perform at their Rock the Garden concerts.

The Jayhawks, Iffy, the Bad Plus, Andrew Broder's Fog and Barb Cohen all played the early RTG lineups (1998-2004), adding local pride to an event where having 1,500 to 3,000 underground music lovers in one place seemed like a huge deal.

Then along came the Current.

On Saturday, a staggering 10,000-plus fans -- all of whom gobbled up their tickets within an hour -- are expected outside the Walker again for the most local Rock the Garden lineup ever. It's also the most significant sign yet that 89.3 the Current is the most powerful music broker in town.

Four of Saturday's five RTG bands hail from the local club scene, including New York-based but Minneapolis-rooted headliners the Hold Steady.

Two of the other locals, Trampled by Turtles and Doomtree, are on tour this summer playing some of the country's biggest festivals. The fourth, Howler, is too young to even know what the scene was like pre-Current. Which might be why the band's gifted frontman, Jordan Gatesmith, was spoiled and/or clueless enough to infamously suggest that his hometown scene is in a lull.

While the Walker staff deserves a lot of credit for RTG's local flavor, it's clearly because of the Current that 10,000 fans jumped at the chance to go. Heck, I'd personally like to take credit for breaking the Hold Steady, Doomtree and TBT, since I spilled a lot of ink on them well before the Current put them into steady rotation. But that isn't what got them national attention or innumerable sold-out First Ave gigs.

"It has completely been a game-changer," First Ave general manager Nate Kranz said of the Current.

In a piece I wrote on the station's one-year anniversary in 2006, Kranz pointed to Low's release party for "The Great Destroyer," which arrived in January 2005 just as the Current went on the air and gave Low its first regular FM radio play in the Twin Cities. The show sold twice as many tickets as any previous Low concert, Kranz said. The oft-cited "Current effect" was already in effect.

Said Kranz last week, "Just look at all the sold-out spring shows we had," referring to first-time headlining main-room gigs by the 4onthefloor, Lucy Michelle & the Velvet Lapelles and Caroline Smith & the Good Night Sleeps. "None of those would have sold out without the Current."

Doomtree's New York-based manager, Doug Lefrak of Feisty Management, acknowledged the early press and fan support for the hip-hop group and its members' solo careers. But when the Current put the group in steady rotation, he said, "That's really when all the doors started opening." And he didn't mean just locally.

"I know for a fact that the other noncommercial stations around the country that have played the 'No Kings' album started doing so because the Current was playing it," he said. "Minneapolis is such a strong music scene in general, the Current just sort of amplifies that. You don't see that kind of relationship between the scene and a radio station in 99 percent of the other markets out there."

Interestingly, Lefrak also represents a Twin Cities band that hasn't received much Current airplay relative to its popularity. Motion City Soundtrack "hasn't always fit the Current's format," he acknowledged, "but we're pushing hard to get them to play the new record."

Local band manager Mark Gehring similarly can cite strong Current support for his "Minnesota Beatle Project" albums and client Lucy Michelle, but not so much for Pert Near Sandstone, which also sold out First Ave this spring.

"Pert Near Sandstone has put in years of work," Gehring said, citing the band's near-constant touring and recording. Still, the little Current airplay it got "undeniably helped raise awareness for the band and [increased] their concert draw," he said.

In short, he said, the Current "helps to expedite the acquisition of new fans, but isn't the be-all/end-all for local bands."

The Current's program director, Jim McGuinn, admitted that the staff takes flak over the stuff it chooses not to put into rotation. He rightfully used that as a counterpoint to criticisms that Current staffers and local music writers can be overly fawning about the scene. Said McGuinn, "We give negative reviews by omission." And the Current omits a lot of local music.

McGuinn provided stats that prove just how much is played, though: Last year, more than 15,000 rotations were split among roughly 600 local acts (past and present). About 40 of those acts were played more than 100 times -- i.e., regular rotation.

However many local acts wind up with frequent 89.3 spins this year, you can bet that four of them are performing Saturday outside the Walker.

Random mix of music news...

Four months since he halfheartedly ran an ad offering his bar for sale, Lee's Liquor Lounge owner Louie Sirian said last week that he has received a few "nice offers" but is still a long way from making a decision. "I'm not sure what I would do with my time if I sold it," said the 76-year-old bar vet. Maybe Wednesday's gig by Texas honky-tonker Dale Watson, who wrote the song "Louie's Lee's Liquor Lounge," will convince him to hang on to it for a while longer. ...

Speaking of that new Motion City Soundtrack album, "Go" arrived in stores Tuesday via Epitaph Records. The disc was recorded locally with Ed Ackerson producing, which -- along the fact that the band returned to the indie realm from Columbia Records -- might suggest the band had stripped things back. Au contraire. "Go" has some of the more sophisticated and ambitious pop noise of MCS' five albums, and probably its best overall songwriting. Foremost among the new tracks is a trickle-to-monsoon rocker called "Timelines." Put that into rotation, Current staff! Motion City will hit River's Edge Fest in St. Paul on June 23 amid a run of summer tour dates. ...

One electronic rock band that doesn't forget the "rock," NIN-echoing duo the New Monarchs hit the Triple Rock on Saturday to tout their second album, "Stay Awake," with BNLX (9 p.m., $6). ... Jim Belushi's favorite summer blues fest (according to the fliers), the Santiago Shakedown marks its 10th anniversary on Saturday at the Bailey Ray's bandshell in Santiago, an hour northwest of the Twin Cities. Performers include the Lamont Cranston Band, Reverend Raven, Johnny Rawls and Sena Ehrhardt. Details at ...

Jeff Tweedy had to back out of Sunday's Kill Kancer fundraiser at the Cedar with Golden Smog, et al., but there might be a surprise guest or two. The tribute to late Soul Asylum bassist Karl Mueller sold out anyway. ... The Gear Daddies, who were part of the original Rock for Karl concert in 2004, are back for another summer gig at the Fine Line on Saturday with Dan Israel opening (9 p.m., $31-$36). Martin Zellar will be even closer to home when he plays the St. John's Block Party in Rochester on July 14 with the Hardways promoting their new album, "Roosters Crow." That's another good one the Current overlooked, by the way.

Follow Riemenschneider on Twitter: @ChrisRstrib