Polk Audio Polk Reserve Series R400 Large Center Channel Loudspeaker, New 1" Pinnacle Ring Tweeter & Dual 6.5" Turbine Cone Woofers Black Reserve R400 - Best Buy
ScanSpeak Discovery R2604/8330 Tweeter Dual Ring Radiator
The Advantages of a Ring Radiator vs. Conventional Domes? (Concave/Convex) | diyAudio