As the "Cautious" video I posted shows, at times different rappers rap in different booths, which is one explanation for the different sound qualities. When Tupac rapped, he would have a habit of waving his arms around, thus not touching the mic. Me, on the other hand, have a tendency of gripping the microphone at the head, which alters the sounds hitting the induction coil located in the magnetic field of the permanent magnet, which is fastened to the diaphragm.