England-born Nolan Lambroza grew up loving metal and was classically trained at Berklee, but his calling? Guiding teen idols to sonic maturity. After he shaped Justin Bieber's redemptive piano ballad "Believe," Sir Nolan came into his own teasing out Nick Jonas' inner R&B lothario and swathing Selena Gomez's sensuality in darkly plush atmosphere. With Carly Rae Jepsen, he finds a blissful coming-of-age mix of vulnerability, yearning, and confidence.