The IC-630 is Russound's flagship in-ceiling speaker.designed for intelligent highs and deep rich lows. Using advanced marterials from the 1" pivoting titanium tweeter to the 6.5" injection-molded polypropylene cone with vapor-deposited titanium, the IC-630's performance will blow you away and will continue to impress you during years of enjoyment. It includes a +/- 3dB tweeter adjustment switch to allow you to adjust for the room's acousitc characteristics. In bright, reflective rooms with lots of hard surfaces, set the switch to -3dB to tone down the highs a bit. In a room filled with large, absorptive items like bulky furniture, thick carpet and curtains, set the switch to +3dB to compensate and reinforce the high frequencies as needed. The patented SwiftLock by Swarm technology allows for quick and easy tool-less installation with the simple press of a button at each of the three mounting dogs.