Speaker system with two or more individual drivers covering two frequency sections or bands. Each frequency band may have more than one driver dedicated to it (many THX certified speakers for instance use multiple tweeters even though the tweeters cover the same area of the audible frequency spectrum). A two-way speaker system usually consists of a woofer/midrange section and a tweeter or high frequency section. Two-way and three way systems are the most common, and two-way systems are particularly common in bookshelf systems.