Fans Wait Until the Stars Come Out : Pop music review: The Summer Jam crowd took the heat and lags between sets to catch name-brand hip-hop and R&B; acts.

Graffiti art banners lined the Irvine Meadows Amphitheatre stage with such messages as “Increase the Peace” and “Unity Thru Music,” but it was an unspoken motto that kept more than 15,000 fans in a jubilant mood for more than 10 hours on Sunday at the KKBT 92.3 Summer Jam: Wait long enough, and the stars will come.

The predominantly African American crowd waited through intense heat, lags between sets, some tepid performances and corny banter to see whether some of the hottest acts in hip-hop and R&B; could groove them harder in person than they do on recordings. In a few cases, the name-brand acts proved that it was actual talent, not just studio resources, that made them star material.

Following sets by R&B; acts IV Example and Usher, Oakland rapper Dru Down amused the crowd with funny dances, bragging rhymes and bass-heavy beats, but he didn’t really get the fans completely on his side until he did a rousing rendition of his hit “Pimp of the Year.”

That underscored another unspoken theme that ran through the day: Just play the hits. Jon B., who’s been dubbed the white Babyface, played one of the day’s more elaborate sets, with a full band complete with background singers and a violinist. He scatted jazz-style, he played keyboards, he wailed like Philip Bailey, but he got absolutely no response from the crowd because he had only one hit to offer, “Someone to Love.”

Some performers proved that all you need is a microphone. Walking into the stands with a cordless mike and doing a tour of the amphitheatre, Doug E. Fresh got people shouting the words to his old hits “The Show,” and “La Di Da Di,” taking them back to the days when party rhymes, not gun metaphors, were the norm in rap.

The only solo performer who came close to recapturing that fervor for the rest of the day was Brooklyn’s Notorious B.I.G., one of the few East Coast performers with as big a following on the West Coast as at home.

The sultry Adina Howard, wearing a tight red top, hip-hugging hot pants and black high heels, played a tightly choreographed set that reeked of sexuality, but Brandy proved that it’s possible to be just as appealing to the eye while showing much less. Backed by the tightest band of the entire show, the 16-year-old singer eased her way through such hits as “Baby” and “Best Friend” with the finesse of a performer twice her age.

Naughty by Nature proved that, following the demise of Public Enemy, live hip-hop on a stadium level is in good hands. R&B; gods Jodeci brought an almost religious fervor to the subject of sex, with the screaming women in the crowd worshiping at their feet like a congregation at the altar. Veteran funk group the Gap Band closed the show, serving mainly as exit music for the bulk of the crowd. (Scheduled performers Warren G and Bone Thugs-N-Harmony both canceled because of deaths in their families).

Ultimately, the Summer Jam proved that it’s still possible to put on a large-scale rap concert without any conflicts or violent incidents. If people of different races and different areas of the Southland can put their differences aside (and accept the necessary high security), maybe promoters can re-examine their reluctance to stage similar concerts. As hokey as it may sound, “Unity Thru Music” was a reality for a memorable 10 hours.