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NEW YORK (AP) — They truly are marching to the beat of their own drum.

It's as though anything Jimmy Iovine and Dr. Dre touches turns to gold: The dynamic duo marked epic-level success when they introduced Eminem to the music world 15 years ago, and their lucrative Beats by Dre business reached blockbuster heights following reports that Apple plans to buy the headphones' parent company, Beats Electronics, for $3.2 billion.

But the music industry veterans have had a string of triumphs, and we take a look at why we never seem to never forget about Dre and Iovine.

Dre, too, started as a producer, but it was for N.W.A., the hip-hop group he was a member of alongside Eazy-E and Ice Cube. The West Coast-based rappers made their stance in hip-hop culture and music history in the late '80s with controversial lyrics and edge, and Dre followed that with his own solo work that topped the charts. Dre is also responsible for bringing forth rap king Snoop Dogg, rap king Eminem, rap king 50 Cent and rising rap prince Kendrick Lamar. Outside of those acts, beats by Dre — literally — include tracks like Tupac's classic "California Love," Eve and Gwen Stefani's Grammy-winning "Let Me Blow Ya Mind" and Mary J. Blige's only song to hit No. 1, the party jam "Family Affair."

Many celebrities and musicians have launched headphones lines, from 50 Cent to Quincy Jones to Jay Z, but no one has come close to Beats by Dre, even before Apple's billion-dollar acquisition. The brand, which debuted in 2008, brought new life to the headphone industry, reinvented the way people listen to music and revived how earphones could make a fashion statement. Dr. Dre is a doctor in the music industry, and Iovine is as needed as an IV.