The audiophile-grade tweeters used in Infinity's new Reference speakers deliver smooth, non-fatiguing sound even at high output levels. The larger Reference multielement and component systems offer a tweeter output level control to optimize system linearity to suit installation location or the listener's preference Harman’s patented (US patent #7,548,631) Plus One cones provide more overall speaker-cone area than other cones in its class - the result is higher sensitivity, increased low-frequency output and accurate music reproduction. Reference speakers are available in a range of standard sizes, and feature a compact design that allows them to fit just about any vehicle on the road today.