Pop music’s universe of celebrities has widened in recent years to include producers and songwriters

LOS ANGELES — Two days before Justin Bieber's 18th birthday he was, as usual, working. He walked into the main control room at Record Plant, a recording studio here, his blue-and-pink high-top Balenciaga alamo rental car las vegas sneakers unlaced, nodding his head to a sinuous beat blaring over the speakers.
On this Tuesday night in February Mr. Bieber was a few weeks into recording his second full-length album, "Believe" (RBMG/Island). The studio was crowded with songwriters trying to turn that beat into a hit; with Mr. Bieber's relatives, alamo rental car las vegas in town for his birthday; with a security guard; with various assistants.
Mr. Harrell is Mr. Bieber's vocal producer, filling a many-layered and amorphous job: part vocal coach, part cheerleader, part sound engineer, part therapist. At this studio he's a star, too: the nameplate on a kick scooter at the front desk just says, "KUK."
Pop music's universe of celebrities has widened in recent years to include alamo rental car las vegas producers and songwriters; they're as crucial to what you hear on the radio as the stars, and increasingly known to the public. But there are deeper levels of highly specialized talent, alamo rental car las vegas just as integral, that often go unrecognized.
Mr. Harrell, 47, is one of those figures, shaping the sound of radio from the shadows. His client roster also includes Jennifer Lopez and Rihanna, and his job is to make sure that the star's vocal is as powerful and flawless as it can be.