People love home theater, but most dread installing it. Its multiple channels of surround sound will immerse you in the action, as appealing to the ears as high-definition TV is to the eyes. But surround sound usually means surround wiring, in the form of the wires needed to connect rear-channel speakers to a receiver.

To clean up that clutter, some manufacturers have opted for wireless connections to rear speakers, but many attempts have been marred by static and interference. Others have tried to simulate surround sound from three or fewer speakers; for example, boutique manufacturer Niro (www.niro1.com) makes a range of systems ($540 to $1,090) that create a wide, immersive sound field from a single speaker. But unlike even the cheapest five-speaker system, Niro's hardware can't make effects sound like they come from behind you.

Yamaha now says it can deliver that last trick with its new YSP-1 receiver ($1,500, www.yamaha.com/yec). This system packs 42 small speaker cones, plus a regular amplifier and surround-sound circuitry, into one 30-pound box, about 40 inches wide and 7 inches tall. Those 42 elements project "beams" of audio that reflect off the side and back walls. Surprisingly, it works.

You do, however, have to work for the YSP-1 first. We had to spend about 20 minutes tweaking its settings to get from flat to three-dimensional sound, with frequent references to the too-short, 60-page manual. This fine-tuning required us to set various menu options via the remote control, including the room's size and shape and the YSP-1's placement.

We could rely on a front-panel readout for basic settings but had to connect the YSP-1 to a TV to see sample room drawings and other controls. A self-calibrating system -- something available on some other home theater gear we've reviewed -- would be a big help in reducing setup time.

Once we had tutored the YSP-1 in the room's shape, we could then choose from stereo, three-beam or five-beam modes that change the way its speaker elements bounce sound off the walls.

The overall result was a large, lush sound field that immerses you in the action just like five speakers. Voice panned smoothly across the room as actors moved across the screen. Hoofbeats charged past us, rather than fading to the sides.

The effectiveness of this varied in three rooms, as did the size of the "sweet spot" where the surround effect was most complete. Obstacles such as large, stuffed furniture weakened the sound, as did curtains. Varying wall textures, gaps and irregular walls could make effects lopsided. Moving around within the area or even turning your head could also weaken the surround effect.

The one thing Yamaha's system could not compensate for was a non-rectangular living room, which weakened or neutralized the surround effect even after repeated returns to the setup menus. Yamaha recommends placing this system in a room whose interior is as close to a smooth, flat box as possible -- advice we could agree with after an audition in a standard-sized room, where the sense of immersion was strong and the listeners' sweet spot more than covered the couch.

We did notice some weak bass output, but that can be fixed -- at additional cost -- by attaching even a modest subwoofer. (Since subwoofers can be hidden, you'd still see only one speaker.)

Despite its heft, the YSP-1 fits nicely over or under most wide-screen TVs.

Unfortunately, it leaves out an FM tuner and can't switch video from one device to another, as most surround-sound receivers do. Its remote control can be programmed to manage a TV, VCR, DVD player and cable box, but not a TiVo digital video recorder.

The YSP-1 is a remarkable accomplishment, but -- like a lot of home-theater gear -- it's not for everybody. It's best for patient, settings-savvy enthusiasts who are not afraid of tweaking and have a sufficiently boxy room ready to fill with sound.

The Yamaha YSP-1 fits over or under most widescreen TVs. But it holds up best in rectangular rooms.