While both bands have the backing of major labels (the Kings are on RCA, while the Machines call Reprise home), receive some exposure on commercial radio and have benefited from a ton of good press (a common hook is that both bands are comprised, in part, of brothers), it looks as if Kings of Leon are poised to break through to a larger audience.

After a shakin’ opening set by Stockholm, Sweden’s Shout Out Louds, a low bass rumble and purple/blue sci-fi lighting announced the Secret Machines.

The New York (by way of Dallas and Chicago) three piece has built a strong cult following on the virtue of a critically acclaimed debut (2004’s “Now Here is Nowhere”) and the recently released “The Road Leads to Where it’s Led” EP. The Machines, Benjamin Curtis/Brandon Curtis/Josh Garza, specialize in a multilayered, hypnotic sound that draws inspiration from psych/prog outfits like Pink Floyd, Hawkwind, Can and Love and Rockets. These influences were readily apparent at The Congress, as the band soared through a restrained “Nowhere Now,” the lysergic “First Wave Intact” and a bold cover of Bob Dylan’s “The Girl from the North Country.” An extremely visual band, the Machines employed all varieties of stage lighting - spotlights, strobing spotlights, colored spotlights, floodlights, stage lamps and floor lights— to further hypnotize the audience. By the time the band reached climax - sounding something like 1,000 graveyard computers coming back to life - some in the crowd were visibly and audibly impressed. Many, however, had clearing been biding time.

The Kings of Leon have a great back-story. The band is comprised of the Followill brothers (who grew up touring the southern US with their evangelist father) and their first cousin. The group released “Youth and Young Manhood” a couple of years back (platinum sales in the UK, alone) to critical acclaim and are riding the success of their sophomore release, “Aha Shake Heartbreak.” The Kings combine gritty southern rock with the commercial ends of garage and post-punk, much in the way that a slew of influential college rock groups - R.E.M, Green on Red, Jason and the Scorchers—did back in the day. They recently were in the much-coveted position of opening up for U2 on the Vertigo tour.

Before they took the stage, the Kings treated the audience to a mix of songs by their favorite bands. Recognizable cuts by Buddy Holly, The Stranglers, The Ramones, The Cars, Prince and Creedence Clearwater Revival were piped in over the PA. These gave way to a choral selection as the lights dimmed and an immense backdrop featuring a Red Indian warrior was unfurled. Then, four young men in t-shirts and pencil-thin jeans emerged. For the next hour, the Kings of Leon wowed the audience with confident, swampy reads of “Molly’s Chambers,” “Slow Night, So Long,” “The Bucket,” “Holy Roller Novocain” and “California Waiting.” The crowd was delirious, showing its appreciation by hurling missiles on stage, pumping fists and singing along to every word (hmmm, it’s kind of like what you’d witness at a U2 show).

If the night proved one thing clearly, it was that the Kings of Leon are shrewd customers, giving the audience a solid good time with just the right amount of edginess. Their “co-headliners,” the Secret Machines, chose instead to challenge the crowd, the rewards of which are not as immediate but may prove to be longer-lasting.