Mastered the rap then fucked up the monitors
Kendrick uses a very clever double entendre here.
1.) The first plays off audio production. “Mastered the rap” (after laying down the verse he also helped master the track in production) “then fucked up the monitors” (the verse was so hot that it messed up the computer monitors they were editing on
2.)“Mastered the rap” (he has mastered the art of rapping) “then fucked up the monitors” (in this case he means people that are “monitoring” his rap career, in that his rap is so good and unique that it fucks up critics cause they weren’t ready for it
Also could be a reference to these, which are a popular speaker among producers, known as KRK Monitors
To help improve the meaning of these lyrics, visit "6'7" by Kendrick Lamar (Ft. ScHoolboy Q) Lyrics and leave a comment on the lyrics box