Wednesday night's Q102 Jingle Ball at the Wells Fargo Center was a not-so-well-oiled machine of back-to-back mini-sets showcasing musical acts, most not well known, performing their radio hits live. Ten solo artists, a duo, and an Australian mall-punk band took the stage, gyrated a bit, performed two to four songs, said, "God Bless," and exited. Within minutes, the stage rotated 180 degrees to reveal the next act. The crowd treated each set as a break from taking selfies with their friends.

Sameness was an issue. In "The Twelve Days of Christmas," it's impossible to remember what your true love gave to thee on the seventh or eighth day, and it's impossible to distinguish between the vocal stylings of Natalie La Rose and Alessia Cara. Swedish pop singer Tove Lo came out on the stage after True Grit child star (and Oscar nominee) Hailee Steinfeld - wearing what Steinfeld had worn. It drove home the sameness of the acts.

The pinnacle of pep arrived with R. City, a Virgin Islands songwriting duo responsible for an album's worth of radio hits by Usher, Rihanna, and Miley Cyrus. A DJ spun their moneymaker medley while R. City rallied the crowd. Post-R. City, momentum dropped. The delay between stage rotations grew. The intermittent commercial breaks started to repeat the same ads for a local beauty school and PGW. Three hours in, no end in sight, even Elvis Duran, the syndicated Q102 morning show host, looked as though he was up way past his bedtime.

Shawn Mendes and Selena Gomez drew the loudest shrieks from the audience - and were also the only acts who surpassed the evening's fair-to-middling bar.

Between Gomez and the headliner - British EDM superstar Calvin Harris - was Charlie Puth. The 24-year-old sat at a piano performing his nagging single "Marvin Gaye" and the chorus of Wiz Khalifa's "See You Again" (his only other contribution to mainstream pop thus far).

By the time Harris took the stage, one of the Q102 DJs was exhorting the crowd to "bring a little Las Vegas to Philadelphia," trying to reenergize the audience, many of whom had filtered out after Gomez.

Harris stood behind a massive DJ booth emblazoned with projection screens as he flailed his arms in turntable fashion. He served loud dance-club anthems to a room of people getting the most bang out of their Jingle Ball buck. By the end of the night, some of the acts had already been forgotten.