The Klipsch RB-81 is the highest-end model of the RB series of speakers (designed to serve as a bookshelf alternative to larger, floorstanding Klipsch products). The RB-81 is notable in that it features a bass reflex front-firing port which lowers turbulent noise and allows the speaker to be set into a cabinet instead of creating the space necessary for the RB rear-firing models. It features an 8-inch Cerametallic cone woofer and a Tractrix high frequency horn with a 1-inch titanium tweeter. The RB-81 has a frequency response of 46Hz-23,000kHz and 1,800Hz high frequency crossover.