This Series Of Speaker Is Optimized For Loud Front-End Clarity And Performance. AB has developed a new type of highly efficient driver aimed at delivering high levels of clean output from stock speaker locations. The SQ midrange speakers feature performance refinements like vented backplate motors, long fiber cone stock, and Kevlar cone bodies resulting in a smooth extended frequency range. The low moving mass design coupled with tight motor tolerance produces ultra-fast transients and high output to keep up with any subwoofer system.