Plus One (patent pending) woofer cones - The GTO507C’s mid-woofer has a cone with more surface area than competing models of the same size. The benefits of Plus One are greater efficiency and bass output.Computer-optimized voice matched passive crossover - The GTO507C, GTO607C and GTO8607C feature an outboard crossovers that has been voice-matched to ensure optimum transistion from the mid-woofer to the tweeter.My-Ti (Mylar/titanium composite) tweeters. Stiff and ligh…