It was going to happen to someone, and it did. Nearly everything that could go wrong in a live, public, broadcast television appearance went wrong for Mariah Carey in her three-song, just-before-midnight performance on ABC’s “Dick Clark’s New Year’s Rockin’ Eve With Ryan Seacrest” in Times Square. At first it was pretty standard fare: She posed, framed by feathers, as a glittering pop princess through a pristine, apparently lip-synced “Auld Lang Syne.”

But then “Emotions” started and, she said as the music played, her monitors weren’t working. (Robert Goldstein of Maryland Sound International, the longtime audio company for Times Square on New Year’s Eve, disputed her complaints: “There were zero technical malfunctions,” he wrote in an email to The New York Times. “Every monitor and in-ear device worked perfectly.”) Beyond a handful of phrases, Ms. Carey didn’t attempt to sing her lead vocals. Meanwhile, both speaking and singing, her voice was considerably lower, huskier and scratchier than it had been during “Auld Lang Syne.”

“I’m trying to be a good sport here,” she said as the backing track to “Emotions” played on. “Let the audience sing,” she urged, and she cued one of her dancers to grab her in a lift. She kept on smiling and strutting in her high heels; she held her microphone toward the crowd. When the song ended, she declared, “That was” — she paused to choose a valid but positive adjective — “amazing.”

Then, with a skirt added to her outfit, and still smiling, she performed her 2005 hit “We Belong Together,” at times holding the microphone far from her mouth or calling out “Happy New Year!” as the impeccable lead vocals continued: more proof of lip-syncing. “It just don’t get any better,” she quipped, husky-voiced again. And the segment was over.