The 683 S2 features a Decoupled Double Dome tweeter - technology evolved from Bowers & Wilkins CM10 speaker. The double dome design uses an extremely thin aluminum dome for lightness, surrounded by a thicker aluminum ring for rigidity. The result is a far more precise treble performance. And while the tweeter looks like it's part of the main speaker, it's physically separated in its own gel-filled cavity, so performance isn't hit by unwanted resonances or vibrations, for a more natural, spacious sound. Serious and accurate bass performance is equally vital to such a room-filling speaker. That's why the 683 S2 features a developed bass driver construction method, using a similar method of bracing to the tweeter with twin layers of aluminum. The richer, distortion-free bass response is sumptuous. As well as advanced bass driver construction techniques and an improved tweeter, the 683 S2 also boasts an FST Kevlar midrange driver. Serious technology, serious performance, but seriously affordable for a speaker of this caliber.