Producer Dr. Dre attends the Premiere Of “American Masters Inventing David Geffen” at The Writers Guild of America on Nov. 13, 2012 in Beverly Hills

*Despite a 13-year gap between studio albums, Dr. Dre has managed to top Forbes’ new list of “The World’s 25 Highest-Paid Musicians,” earning an estimated $110 million from May 2011 to May 2012.

Dre’s bested such competition as Britney Spears, Taylor Swift, Justin Bieber and Kanye West, all of whom made the cut, and was nearly $30 million more than the man who came in at #2 on the list, Roger Waters of Pink Floyd.

The last single released by Drew was “I Need A Doctor,” in February 2011. And while royalties from his expansive back catalog and payment for performances like his headlining set at the Coachella fest added to his bank account, the majority of Dre’s wealth these days comes one very profitable source: his line of Beats headphones, earphones and accessories.

Dre founded Beats Electronics with Interscope/Geffen/A&M chairman Jimmy Iovine in 2006, and the company produced the first set of Beats by Dr. Dre headphones in late 2008, and while the profits were certainly there, he really cashed in last August, when Taiwanese corporation HTC purchased 51 percent of Beats for a reported $300 million.

According to Forbes, that purchase netted Dre a cool $100 million, and, less than a year later, HTC decided to sell back half of its stake to Beats (though they still retain exclusive rights to use Beats Audio technology in their mobile devices).

Dre and Iovine have only continued to expand their Beats empire, creating a line of boomboxes to go along with their headphones, and Beats speakers can also be found in the Chrysler 300, the Dodge Charger and a line of HP laptops, too.

There are also reports that Beats is branching out into the smartphone market, with a line of devices manufactured by HTC, and making preliminary moves towards launching a custom Beats television, partnering with a manufacturer to create “an Apple-like experience that extends from a phone to a TV to a tablet to a laptop … much in the same way Apple does with Apple TV, AirPlay and iTunes.”

Beats also acquired online music service MOG this summer, for a something in the neighborhood of $10 to $16 million.

At the end of the year, Beats’ five-year deal with Monster Cable Products — which was the exclusive manufacturer of their headphones and speakers — will come to an end, meaning that the company will go forth on their own …certainly a risky move, notes , but, given they control a reported 53 percent of the $1-billion-headphone marketplace, one that could pay even bigger dividends for Dre.