Klipsch R-5650-S II In-Wall Speaker - White (Each) Dual 1 (2.54cm) Titanium diaphragm compression driver mated to pivoting 90 x 90 square Tractrix Horn 6.5 Cerametallic cone woofer Two vertically stacked Tractrix Horn-loaded tweeters maximize surround sound effects Horn-loaded technology increases acoustic output while significantly reducing distortion IR receiver knock out