I used to own a 3 way floorstander with a tonegen ribbon tweeter (Heybrook sextets) and those ribbon tweeters were the sweetest treble I ever heard, and neither bulky nor inefficient.
Ring radiator tweeters - the future?
A technology developed by Scanspeak that hasn't penetrated the audiophile market, but Polk started using them - and their fans say it produces better high end within the same price range. A brief froogle reveals JBL offers them as components. Could this technology end the perpetual silk dome vs. titanium dome debate?