The most rock ‘n’ roll thing about “Rocktopia,” a misbegotten new concert mashup of classical music and rock standards that opened Tuesday at the Broadway Theatre, comes in the second act, when one of the chorus members perched on a riser on stage right whips out his orange cellphone and starts recording as Chloe Lowery belts out “I Want to Know What Love Is.”

The chorus singers are all members of the New York Contemporary Choir dressed as if they’re going to hit the clubs after the show, and definitely not the same clubs. They’re also the most enthusiastic people on the stage, grooving to the beat and pumping their fists throughout a two and a half hour production.

I wish I could say the same thing. Maybe it’s that the very concept of “Rocktopia” feels so dated, like a glorified field trip to the local symphony hall for a High Art-meets-Low Art lesson in music appreciation. (The idea of blending rock and Rachmaninoff is not new.)

Maybe it’s the fact that co-creators Randall Craig Fleischer (who’s responsible for the both the arrangements and conducting duties) and Rob Evan (a Broadway vet with a booming baritone) stick mostly to obvious choices, almost entirely from the prog rock era of the 1970s and ’80s. (The most recent tune is Muse’s “Uprising,” which, oddly, is paired with Pink Floyd.)

Maybe it’s the fact that some of Maestro Fleischer’s mashups don’t really work, like Tchaikovsky’s “Romeo and Juliet” overture segueing into Patti Smith’s “Because the Night” or pairing Mozart’s “Eine kleine Nachtmusik” and Styx’s “Come Sail Away.”

Maybe it’s the upstage LED screens, which instead of identifying the classical pieces being performed (they’re not included in the Playbill either), offer the silliest and most on-the-nose visuals imaginable. We get scenes of European castles as Celtic violinist Máiréad Nesbitt leads the New York Contemporary Symphony in a snatch of Mussorgsky’s “Pictures at an Exhibition” (see, you’re hearing classical) and then jump to skyscrapers and urban traffic as Rob Evan croons U2’s “Where the Streets Have No Name.”

Read the rest of my review for TheWrap.