The small footprint and point-source radiation of a concentric driver setup (tweeter mounted on the dust cap of a mid/woofer) make a lot of sense for installed use, so it's no surprise to see Tannoy
-- a longtime proponent of its Dual Concentric drivers -- would use the technology for its CVS4 Micro in-ceiling speaker. The 0.75-inch tweeter is paired up with a 4-inch bass unit in a can-type enclosure for easy in-ceiling installation, even in low clearance installs. Better still, these you can feed these either 70V or 110V and everything will be ok thanks to the built in transformer. Bad news for the bassheads, though -- the low end only reaches to 90Hz.