Acapella Sphäron Excalibur Speaker

Audiophiles who want to impress their friends—and I seriously doubt there are any who don't—would be hard pressed to do better than a pair of Sphäron Excalibur speakers from German horn specialist Acapella. But you'd better have a pretty big room to comfortably house these beautiful beasts, which stand over seven feet tall and weigh 1364 pounds each.

The first thing most folks notice is the two large circular horns that measure 41 and 23 inches in diameter and reproduce the low-mid and midrange frequencies, respectively. At the throat of each horn is a modified but otherwise conventional speaker driver, not a compression driver as in other horn-loaded speakers.

The highs are handled by Acapella's so-called ion tweeter, mounted between the two larger horns. There's no diaphragm at the throat of its 6-inch horn—instead, the current in a high-voltage arc is modulated by the audio signal, causing the nearby air molecules to vibrate in response. With virtually zero mass, the ion tweeter can reproduce frequencies as high as 100kHz, though in this case, it's limited to 30kHz.

A rectangular, sealed bass cabinet houses four 15-inch woofers that cover the low end of the spectrum, giving the entire speaker an overall frequency response from 20Hz to 30kHz (±7dB). That's a fairly wide tolerance, which makes me a bit suspicious, but I haven't heard these behemoths, so I can't say how it ultimately affects the perceived sound.

What would you pay to wow your friends when they see the Sphäron Excaliburs in your listening room? Get out the Titanium card—a pair will add $455,000 to your balance. Can't afford that much? Too bad—you'll just have to settle for something less impressive.