Sigur Ros, Aphex Twin Heat Up Barcelona Fest

Sounds of old school (Terry Riley) and new (Vladislav Delay) mix and mingle as annual Sonar event kicks off.

BARCELONA, Spain — Catalonians know a thing or two about the slow build, as evidenced by the bewildering 18-plus hours of music at the opening day of the eighth annual Sonar International Festival of Advanced Music and Multimedia Arts.

There is no better location from which to scout the front lines of electronic music's forces than Sonar, which unites the scene's wide range of sonic renegades and parades them through the vibrant city. Thursday's performers alone — from Vladislav Delay to Terry Riley, Sigur Rós to Carl Cox and Darren Emerson, Sonic Youth to Aphex Twin — were enough to send a visitor home both satisfied and enlightened.

From the first record, reflecting the midday sun, spun at noon until the light shone again early Friday morning on still-crammed dance floors, Sonar was in full swing — and it was just getting started, with two more days of stunning lineups still on tap.

Like other global techno gatherings such as the Winter Music Conference in Miami Beach or Berlin's Love Parade, Sonar's attendance has grown exponentially with the music's ascent over the last decade, as witnessed by the 10,000-strong flock Thursday night. It has also managed to avoid those festivals' pitfalls, however, by sticking to its guns as a celebration of electronic music's artistic core and providing a glimpse at what the leaders of the avant-garde and the experimental are up to today.

Divided somewhat manageably into day- and nighttime sections over three days — the former presented on four stages at the Centre de Cultura Contemporània in downtown Barcelona, the latter in three hangar-like spaces (one outdoors) at a massive expo center west of the city center — Thursday's sun-dappled warm-up was capped by a solo outing from Terry Riley, who along with Steve Reich and Philip Glass is considered one of the gurus of experimental electronic music in its myriad guises.

To an overwhelmingly youthful crowd that appeared well informed of Riley's far-reaching influence, the composer moved fluidly through a range of styles. One piece found him on the piano, wowing with a steady harmonic pulse with one hand while fluttering out a playful rag-like blues with the other, combining minimalism and jazz with aplomb. Moving over to a synth for his next piece, Riley triggered a stuttering electronic rhythm that showed he's been keeping up with the techno Joneses, and he accompanied it with soaring raga-influenced scales, even adding a few Eastern chants along the way.

Riley's minimalist aesthetic has been all the rage with the latest crop of experimental producers (whether they're aware of it or not) over the last year, not least among them the Finnish phenom Vladislav Delay. Performing from his achingly spare and deliberate oeuvre (he will present his deep-house persona, Luomo, Friday night) in the Capella dels Angels (Chapel of the Angels) Thursday night, Delay's cascades of gurgling washes swirled through the chapel's chambers, enchanting and exciting as they soared.

At Sonar by Night, the arty Icelandic ensemble Sigur Rós, a last-minute addition, revealed that they, too, can achieve great musical heights with an uncomplicated palette. Following a performance by Sonic Youth that further highlighted new and old by presenting works by pioneering experimentalist John Cage and Yoko Ono (both covered on their 1999 self-released collection, Goodbye 20th Century), Sigur Rós began a set that continued to swell in intensity throughout its 45 minutes.

First accompanied by a guitarist and two keyboardists and eventually surrounded by seven with the addition of a violinist, cellist, bassist and drummer, singer Jon Thor Birgisson, with bowed guitar, effected a pained-ecstasy expression to accompany his spine-tingling vocal emissions, and the look never left his face. When the band's gradual arch hit full tilt — on "Svefn-G-Englar," from their 1999 album Ágætis Byrjun, and the closer — the effect, straight outta the hypothalamus, was simply breathtaking.

Aphex Twin, perhaps techno's most directly descended minimalist, dispensed with any formalities upon taking to the decks for his much-anticipated DJ set, embarking on the sort of distorted, hyperactive drum'n'bass excursion that has become his trademark in recent years. The man (a.k.a. Richard D. James) who built an infallible reputation on tranquility and subtlety has entered the realm of the inexplicable, and, often, the undanceable. Aphex followed on the heels of an excellent live set by the U.K. duo Plaid (Ed Handley and Andy Turner), whose matching consoles and flat-screens emit reliably warm and creative dance grooves nearly every time they perform.

Across the hall of the expo center in SonarClub, beats of the more conventional, but by no means generic, variety could be found pounding out of the loudspeakers via the expertly manned turntables of Darren Emerson and Carl Cox, who kept the dance floor moving until dawn with a mix of hard house and techno, including what appeared to be the club debut (spun by Cox) of Green Velvet's "Lala Land," the first single from his upcoming album (see "Green Velvet Completes Whatever, His Most Personal Work").

The eighth annual Sonar International Festival of Advanced Music and Multimedia Arts ends Saturday.