The black dots initially were developed to help lengthen drumhead life. Up until black dots all you had was diplomats, ambassadors, and emperors. So the dot was basically another piece of Mylar to go through to strengthen the head and then they became their own sound. They were the hippest head development at the dawn of the 70s. If you want to hear black dots recorded really well, listen to any Tony Williams when he started using his big yellow Gretsch kit. You’ll hear a sound that’s hard to replicate with other heads.