A mega-festival both sunny and downbeat

It was hard to tell by the way he unenthusiastically mumbled the words, but Aqualung singer Matt Hales provided the best motto for this year’s South by Southwest Music Conference.

“Hooray for London,” Hales said while opening a SXSW showcase with two other bands from that rock mecca on Friday.

The piano balladeer’s mopey, gray delivery proved to be a spot-on reflection of a lot of the U.K. music that took center stage at the 19th annual industry fete, which lasted Wednesday through Sunday. SXSW is known for its sunny skies and party atmosphere, but this year a new crop of downbeat British buzz bands reigned over the parade.

Aqualung and most of the other 1,350 acts with SXSW showcases were overshadowed by the two bands that headed up Friday’s London invasion, Kasabian and Bloc Party. Drawing from the Cure, Echo & the Bunnymen and My Bloody Valentine, these groups’ sullen moods were offset by up-tempo rhythms and pulsating, edgy guitars.

Two other hot young English bands, the Kaiser Chiefs and Futureheads, also generated lots of enthusiasm sharing the lineup Thursday night with a holdover from the last wave of Brit-pop, the Doves.

The U.K. attack wasn’t all by Anglophile guitar-rockers. London-based rapper M.I.A. had attendees waiting in line for two hours (many to no avail) for her Thursday night set at the 300-capacity Elysium dance club, an improperly sized booking that proved how fast her star is rising.

Too bad M.I.A. didn’t follow the cue of moody, violin-driven Irish rock group the Frames, who seemed to have a gig every five hours during the festival’s five days. At the famed Antone’s blues bar on Friday, the Frames’ singer showed his true colors -- black and pitch-black -- while explaining that “Lay Me Down” is about when he bought a girl a burial plot to try to win her heart.

A couple of older British rockers, Robert Plant and Elvis Costello, were among the veteran artists using the week’s hip cache. Plant got in a whole lotta plugs for his new CD, “Mighty Rearranger,” as the festival’s keynote speaker. But he also gave a boost to the independent radio programmers in attendance, saying he sent in a donation to a public station in Portland, Ore., after hearing their on-air sales pitch: “They promised to never play ‘Stairway to Heaven.’ ”

The business tone of the conference, hashed out by day at the Austin convention center, was surprisingly optimistic. New technologies and packaging gimmicks, from dual-discs (CD plus DVD) to ringtones (music on cellphones) to innumerable takeoffs on the iPod and iTunes were being cited as great white hopes.

However, the outlook continued to sound bleak for the major record companies, offset by several years of declining album sales save for last year.

For musicians, South by Southwest can be frustrating for its snippet-like pace, which typically doesn’t provide for sound checks or attentive audiences. As the singer of Montreal’s charming space-rock band Stars joked, “It’s like ‘The Apprentice’ of indie-rock. You have 20 minutes to impress us. ‘OK, go!’ ”

Soft and romantic French singer Keren Ann came off less than sweetly at her set Saturday night, where she complained, “I can hear a girl in the back talking about her cousin more than I can myself.”

Another mellow buzz kid, Norah Jones protege Amos Lee, on tour with Bob Dylan and Merle Haggard, showed his experience with impressing big and disinterested crowds at a large Austin Music Hall performance.

Also flying into town off a high-profile tour with Alicia Keys was classic-styled R&B; singer-songwriter John Legend, who reminded the audience he’s not exactly a newcomer by playing bits of the Kanye West and Jay-Z songs he performed on. His own gems such as “She Don’t Have to Know” would have been enough.

A few old acts actually tried the opposite: Billy Idol and a half-full lineup of the New York Dolls, featuring David Johansen and Sylvain Sylvain, each hoped their long hiatuses would spark new interest. No such luck.

Faring better in the reinvention department was Son Volt, with frontman Jay Farrar’s all-new lineup ably bringing back the old harmonious twang-rock sound that was missing in his solo work.

Meanwhile, indie-rock faves Sleater-Kinney had their usual three-piece lineup but showed off a new soulfulness while previewing a new album for Sub Pop Records.

Plenty of unknowns also got noticed. The Heartless Bastards are a gritty Ohio blues-trunk trio with a frontwoman who wails like Robert Johnson. Swedish quartet the Shout Out Louds did the moody Brit-pop thing better than a lot of the English bands.

Even Seis Pistos, a punk band from Mexico, got in on the British rock trend with a rousing Spanglish rendering of “Stairway to Heaven.” It was rowdy and energetic enough for even Plant to probably stop hawking his new album so much and just marvel at it.