These are the four-way speakers that provide the clearest three-dimensional soundstage performance available. Made in England by Bowers & Wilkins, regarded as the world's leading innovator of speaker technology, they deliver optimal sound quality by eliminating cabinet coloration-the unwanted sound that radiates from the back of a speaker driver. Mathematically precise, tapering wave-guiding tubes house each unit's 1" and 2" tweeters and 4" mid-range driver. Rear-traveling sound waves are channeled, absorbed, and dampened, resulting in pure sound coming from the front and none from the back-the pattern of vibration is verified to within 1/3000th of a millimeter using laser-doppler velocimetry. Each has a powerful 12" bass driver housed in a curved, spiral-shaped tube that allows sound waves to travel its length without reflection. The speakers' active crossover network frees each driver to operate purely in its own frequency band (unlike typical passive crossover designs) for sound that is crisper, clearer, and more vibrant. Requires four separate amplifiers per speaker (not included). Their enclosures are handmade from fiberglass-reinforced ABS for durability and finished with the same paint and lacquer system used for German luxury automobiles. Black, Blue, or Silver. Special conditions and guarantee limitations apply. 43 1/2" H x 17" W x 43 1/2" D. (192 lbs.)