Possible Clues:

• Eminem's mentor
• Doctor of music?
• Beats Electronics co-founder, familiarly
• Death Row Records co-founder, familiarly
• Titled rapper
• Dr. with six Grammys
• "The Chronic" Dr.
• Dr. who co-founded Death Row Records
• Beats by Dr. ___ (headphone line)
• 'Dr.' of hip-hop