Evans‚Ñ¢ EMAD‚Ñ¢ resonant series features an offset 4" microphone port in a single ply of 7.5mil film. Similar to the EMAD‚Ñ¢ batter a black, noise-free plastic sleeve holds a foam dampening ring around the edge of the micorphone port which controls overtones; enhancing pitch focus and attack.