The versatile S1.8SIW is a 3-Way in-wall surround speaker. The S1.8SIW is engineered for exceptionally smooth off-axis performance and an 8" woofer provides high power handling and exceptionally smooth midbass. The S1.8SIW incorporates exclusive, patented S4X crossover and driver-control technology, which makes possible virtually perfect integration of drivers which are ideal for their intended frequencies. S4X also provides greatly increased control over frequency response, phase, and impedance, resulting in superior performance and imaging. Because of S4X technology, any of Induction Dynamics' speakers can be used to build a custom home theater system. Your S1.8SIW can be combined with any of our center and surround speakers, be they in-wall, on-wall, or free-standing.