Spreading the Jam a Bit Too Thin?

The problem with marathon radio station concerts is that they give you almost too much of a good thing.

Who doesn’t want to see a dozen or so of the season’s most popular acts together on one stage?

And in the case of KKBT’s fifth annual “The Beat” Summer Jam on Sunday at Irvine Meadows Amphitheatre, the capacity audience was treated to music by KRS-One, among the most influential figures ever in rap; Missy “Misdemeanor” Elliott, as hot a singer-writer-producer as you can find these days in hip-hop; and Nate Dogg, whose “Nobody Does It Better” single is helping the Long Beach singer finally reach the stardom that has long been predicted for him.

And that’s just getting started.

There were so many acts that it seems as though it would take nine hours--the actual length of Sunday’s benefit concert--to adequately introduce them, much less let them perform sets that in some cases lasted 45 minutes or more.

Also appearing: A Tribe Called Quest . . . WC . . . Jon B. . . . Monica . . . Montell Jordan . . . Next . . . Chico DeBarge . . . Big Punisher . . . Jermaine Dupri . . . Xzibit . . . Michel’le and Mya, among others.

Unfortunately, the allocation of time Sunday wasn’t always satisfying.

Some acts didn’t have enough time on stage. Dupri, who has one of the nation’s Top 10 albums at the moment, only did parts of three songs in what amounted to a 10-minute hello. Elliott’s role was no less tantalizing.

Some acts had too much time. R&B; performers Jordan, Next and DeBarge, all of whose music relies heavily on love songs, failed to get more than a lukewarm response from the crowd. While their sultry songs work well on the radio, the packed house at the outdoor amphitheater clearly favored the up-tempo tracks from the bill’s rappers.

Artists with rich musical histories understandably produced the best performances. KRS-One, who helped introduce social commentary to mainstream rap in the ‘80s, delivered the concert’s most invigorating set, a furious medley that included selections from his decade-plus recording career.

After hearing the crowd sing the chorus for his song “Jimmy,” KRS-One and his crew returned to the stage for the only encore of the afternoon. Although he didn’t perform the selection that his fans were chanting, he recited a touching poem about love that he dedicated to his young daughter.

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Concert closer A Tribe Called Quest also benefited from having a stockpile of hit songs. When DJ Ali Shaheed Muhammad played the instrumental for “Bonita Applebum,” people began dancing in the aisles with full-fledged smiles on their faces.

The intensity continued as Tribe rappers Q-Tip and Phife provided animated renditions of some of their other popular songs, including “Scenario.”

Nate Dogg, who rose to prominence as the crooner for Death Row Records, delighted Summer Jam patrons by opening his set with “Just Another Day” and “These Days,” two selections from his new album, “G-Funk Classics Vol. 1 & 2.” Warren G joined him for a smooth performance of their “Regulate” single. Nate and Warren kept the crowd captivated with energetic performances of “Nobody Does It Better” and “Ain’t No Fun.”

This intensity was only amplified when rap veteran WC took the stage. Employing a number of classic rap stage show techniques, such as call-and-response chants, the MC roused the crowd to a fever pitch with his rendition of “Just Clownin’.”

While the sets from the first 10 artists ran smoothly, a fight broke out shortly after the beginning of singer Jon B.’s set. When members of the audience rushed the stage and attacked some of the security guards, Jon and his backup band departed.

The situation was resolved after a few moments, but both the audience and Monica, the next performer, seemed tense as she sang her hit “The Boy Is Mine.” The mood lightened when a member of the crowd stood in the aisle and captured Monica’s attention with some sexy dance moves. It worked. The teenager invited the fan on stage where he continued dancing and was rewarded with a hug.