Let's face it, home theater is more fun when you can share it with others. There's nothing quite like inviting other movie fans over, settling into sofas or comfy armchairs, and letting the experience take over.

But home theater aficionados have long agonized over the problem of the "sweet spot," the single seat in a home theater where everything sounds best. Do they give up the hallowed seat to a guest, or keep it to themselves? Does everyone trade, after the mid-movie break for popcorn? All too often, you end up with three people crammed onto a small loveseat, trying to get the best possible sound.

A company named Audyssey, founded by a handful audio experts at the University of Southern California (including THX inventor Tom Holman), took aim at this problem. They came up with something called MultEQ XT. It's a technology designed to provide the largest possible audio sweet spot, so multiple listeners can enjoy the sonic advantages of the best seat in the house. And it may seem like the kind of thing engineers only use in state-of-the-art theaters, but it's turning up in home theater receivers from Denon.

The Denon AVR-3806 receiver is one of several with built-in Audyssey MultEQ XT technology.

Now, at Crutchfield, we've seen various auto-calibration and room EQ technologies come and go, and when we first heard about Audyssey it sounded like more of the same. But it's actually quite a bit different. Most other systems we've seen can achieve noticeable improvements at a single listening spot, although that may actually reduce audio quality for other seats in the room (Bose®'s ADAPTiQ™ is an exception, taking readings at five different locations). Usually, those systems rely on boosting certain frequencies so they are more audible at that position, and delaying certain speakers.

Audyssey, on the other hand, says they have come up with a recipe for making an entire listening area sound superb. To do so, they concentrate on reducing or eliminating unwanted peaks or troughs in the frequency response that are caused by the room itself. They also tweak delay times so the sound from each speaker arrives at your ears at the exact right moment. Finally, and most unusually, Audyssey lets you identify between six and eight primary listening positions — a detail that is surely of interest for anyone who recently watched a blockbuster DVD while smashed into a single sofa with the entire family.

Naturally, we had to try it out. So in the training room at Crutchfield, a handful of interested listeners went and sat down amidst seven speakers and a subwoofer, all powered by the Denon AVR-3806. Before we started listening, however, we got our Denon rep to walk us through setup.

Setting up Audyssey

The setup process didn't seem too complicated, although I wouldn't have wanted to try to puzzle through the menu choices without a manual. You place the microphone (all the Denon receivers with Audyssey include one) at your first listening position, and start the setup process. A loud, somewhat unearthly noise begins repeating itself at one speaker, until the microphone has transmitted the data the receiver needs. Then it switches the signal to the next speaker, until it works through all of them. When it's done with that listening position, you move your microphone to the next seat, and Audyssey starts over for that spot. Once it's tested for every listening position, it tabulates the results and sets an EQ curve and delay times for your system.

Interestingly, the whooping noise generated when the system is analyzing the environment runs the full range of human hearing, from 20 to 20,000 Hz. Apparently, not all systems that do microphone-based auto EQ calibration use such a complete signal to test the environment. (The problem with using a limited signal is that the system can't correct for what it hasn't heard: for example, a problematic dip in low frequencies or an ugly peak in high frequencies.) Another useful tidbit: along with measuring your room, the setup process also makes sure your speakers are in phase, just in case they've been connected improperly. Very handy.