Mixing vocals over mastered beat.

Hey whats up, I like the videos Ive been seeing from you guys, so here I am on the forum hoping I can get some guidance along the way. A friend and I started recording alot of hip hop recently, we have our first quarrel haha. He insists on mastering the already mastered beat with the new vocals together. I personally think it kills the already mastered beat, BUT I havent really found the best way to fit the new vocals into the mastered beat. I came across a video of a guy using a sidechain comp to comp the beat in spots where the vocals were louder, I havent tried it yet but Im wondering what your input would be. Thanks!

hey, good question... no, you do not want to remaster an already mastered track... simply set up a new session to record in 48K ... record vocals regularly, mix them (volume, pan, eq, comp.. FX.. etc...) once u are finished.. bounce the track as a wav WITH DITHER at 16bits... then... go online, find a program such as ITUNES and convert the WAV to an MP3 ... that's all you can do with a mastered beat... Good Luck !