Jack White rocks at Firefly Music Fest in Dover, Del.

On the first day of the Firefly Music Festival in Dover, Del., most of the glitches were minor. Friday's sprinkles never turned to full-fledged rain, although they came close at the start of Jack White's headlining set. The traffic to the Woodlands at Dover International Speedway was as good as could be expected for a venue that has few access arteries. The promoters were "thrilled with the numbers," although they had not released official attendance figures; before the three-day festival, which featured nearly 50 acts, with the Killers headlining Saturday and the Black Keys Sunday, they had hoped for about 30,000 each day, and many ticket packages sold out in advance. The dozen performances were punctual. The sound from all four stages was excellent. Almost.

When White opened with the early White Stripes song "Dead Leaves and the Dirty Ground," his voice was blaringly clear, but the instruments were woefully muffled. The problem continued until midway through the second song, "Freedom at 21," from his solo album Blunderbuss, at which point the sound popped into place. From then on, White's set was ferocious.

White is traveling with two bands, one all male, one all female; Friday was the guys' night, and they rocked hard although without the garage-band directness and seeming camaraderie of the White Stripes. White included a generous sampling of his work with the Raconteurs, the Dead Weather ("I Cut Like a Buffalo" was a hard-funk highlight), and the White Stripes, including a countrified "Hotel Yorba," dense, squealing versions of "Ball and Biscuit" and "Seven Nation Army," and deep-cut surprise "Hello Operator."

The reunited Wallflowers kicked off the afternoon main stage with a set heavy on old hits — "6th Avenue Heartache," "Three Marlenas" — plus glimpses of their forthcoming album. Jakob Dylan and company covered "(What's So Funny About) Peace, Love and Understanding," and covers were common throughout the day. Philly's John Legend opened with Bob Marley's "Redemption Song" and, amid his own soulful R&B hits, earnestly paid tribute to Stevie Wonder, Harold Melvin & the Blue Notes, and the Beatles. Mayer Hawthorne, on the backyard stage, romped through Hall & Oates' "You Make My Dreams Come True," which fit neatly with his own Motown/Philly soul/Detroit funk homages. Hawthorne taught the enthusiastic crowd dance moves and, fortunately, did not jinx the day by singing his song "I Wish It Would Rain."

The Firefly vibe was comfortable and easygoing, even during aggressively loud competing sets from Bassnectar and Silversun Pickups. Pop-up restaurants provided reasonably priced food; Delaware's Dogfish Head Brewery had a large tent full of its craft beers, including a new Firefly Ale, and a wine bar and Jack Daniel's stands provided other non-Bud alternatives. Friday was too windy for the hot-air balloon rides, but not to play vintage arcade games, hang out in hammocks in the woods, or watch the Phillies game in the brewery tent. All that's needed is for Firefly to define itself musically, as has happened with Bonnaroo (identified with jam bands) and Coachella (identified with indie superstars).