Urban stars formulate a plan in live show

Near the end of N.E.R.D.’s concert-closing set at the Sprite Liquid Mix Tour on Friday, group leader Pharrell Williams encouraged the scores of people on the periphery of the Verizon Wireless Amphitheater’s stage to help him belt out his group’s spicy single “Lap Dance.”

Friends, rappers, break-dancers and other hangers-on soon flooded the stage, resulting in the type of all-encompassing organized confusion that has come to typify Williams’ work.

The singer-rapper-producer is best known as half of the Neptunes, a production team that has crafted hits for everyone from Snoop Dogg to Nelly to Justin Timberlake.

In addition to being one of hip-hop’s hottest producers, the Virginian, who is joined in the Neptunes by Chad Hugo, also has a rock fetish. With N.E.R.D., Williams Hugo, rapper Shay and backing band Spymob explore everything from the perils of drug abuse to escapism. Williams’ varied, broad-based approach has earned N.E.R.D. a diverse following, one that seemed as much punk as hip-hop on Friday.

As headliners of the Sprite Tour, an extravaganza that also included a second stage of artists as well as a festival-like atmosphere complete with basketball courts and car displays, N.E.R.D., as well as undercard acts the Roots and Robert Randolph & the Family band, demonstrated that so-called urban artists can excel at live shows.

It’s true that hip-hop-oriented performances, which are often panned by critics, typically feature a rapper, some hype men and maybe a DJ, and rarely suggest any sense of choreography or planning. It’s more like a free-for-all.

Friday’s show signaled an evolution of the genre, as veterans the Roots delivered their typically tight routine, one that featured a sharp medley of songs from a Tribe Called Quest and Ol’ Dirty Bastard, intense guitar solos and impassioned percussion sequences.

Although they’re more rock or blues than hip-hop, Randolph and his band delivered a knockout 40-minute performance toward the start of the seven-hour event. Led by Randolph on pedal steel guitar and vocals, the quartet easily won over a crowd that appeared to be unfamiliar with its back-home grooves.