One show, two courses of R&B;

It’s the moment that the rabid female fans in the audience have been salivating for at the Trey Songz and J. Holiday show Friday at the House of Blues: Songz is finally going to take his shirt off. It couldn’t have come any sooner, because he had pretty much lost the crowd to this point with a lackluster performance that dwelled too long on dreary R&B; ballads.

But could he redeem himself?

Songz robotically unbuttons his shirt. He seems unhappy or perhaps tired. The live five-piece band sounds slightly offbeat and off-key, but the familiarity of the hook to “Last Time” is enough to save it.

He coyly pulls his tuxedo over his shoulder, then puts it back.

“Spread your lovely legs out,” he urges in a sultry tremolo about the temptations of infidelity, “I know your favorite is the kitchen.” The ladies scream in anticipation.

By the end of “I Gotta Go,” Songz recommandeers the crowd, leading them through an easy, swaying two-step as he sings about the forces of attraction keeping him from his obligations outside the love chamber. “I don’t want to leave,” he cries. “I don’t want to go right now!”

At long last, he rips off his white tank top, revealing a V-shaped torso and a washboard stomach. Pay dirt.

Trey Songz and J. Holiday represent two different R&B; archetypes.

Songz is the sensitive and attentive, designer clothes-wearing dreamboat. Holiday the more dangerous thug crooner with the requisite grainier vocal texture and countrified flavor. So there’s something for everyone.

When Holiday emerges on the light-speckled stage, it’s clear that the energy level is going to be much higher. He doesn’t just stick to his own repertoire but instead acts as a kind of emcee, hyping up the crowd as his band plays thigh-pumping breaks of songs culled from a vast, collective hip-hop consciousness, such as “Pop Bottles,” “Before I Let You Go” and “The Rain (Supa Dupa Fly).” The musicians play with fury, as though they were raised on some unholy combination of Quiet Riot and Bad Brains.

And though the tempo slows at times, the emotional intensity of Holiday’s performance does not. He performs “Laa Laa,” his ode to cannabis, while sitting on a stool and bathed in saffron light, bringing to mind D’Angelo’s “Brown Sugar.” Then with a twist of wordplay, he transitions to another song about breathing, or lack thereof: “Suffocate.” “Got me looking at this phone,” he admits. “Every time it rings, I hope it’s you, girl.”

Channeling a preacher cadence, Holiday asks, “How many freaks do we got in the building?” The quasi-churchiness melds into a crunk-punk interpretation of his most anticipated song, the erotically titled “Bed,” as thousands of dollar bills come raining down from the ceiling for the final performance.

And, yes, he takes his shirt off too. But that’s beside the point.