Let's get one thing straight from the get-go - most simulated surround sound "bars" (each manufacturer has a different name for this type of product) will not sound as good as a floorstanding surround sound 5.1 or 7.1 speaker system. Therefore, we will not judge them against the latter but against other competing sound bar products. All-in-one simulated surround sound solutions, such as the Yamaha YSP-4000, serve a very specific market: those who don't want to deal with the wires of a full 5.1 or 7.1 surround sound speakers or simply don't have the real estate in their media room to devote to the same, but who still want to enjoy compelling surround sound. These sound bars are a great match aesthetically to flat-panel sets, and offer a vast improvement over your TV's built-in speakers.

Yamaha's Digital Sound Projectors were the first to market in this product category. The YSP-4000 ($1,800) is the company's top-end model, and offers a surprising amount of features in what looks like just a simple, long, skinny speaker. For example, it has 1080p/720p HDMI switching--which means users that don't have a lot of HD sources can use the YSP-4000 in lieu of a receiver, if they so desire, which makes sense, as multiple speakers usually dictate the need for a receiver. (If you have more than three HD sources, consider getting a receiver and separate surround sound system or external video switcher.) The unit is XM-ready, includes an FM tuner, and upscales video to HDMI.

Audio performance from the YSP-4000 is really up there for this product category, offering believable simulated surround sound, thanks to 120 Watts of power to 40 different drivers and two 4.25-inch woofers. The technology works by reflecting sound off the room's walls, so irregular walls, excessive furnishings, and wall hangings can and will affect the quality of the sound from room to room. Yamaha helps account for these inconsistencies through the intuitive IntelliBeam auto setup calibration system. You just plug in the included microphone, call up the feature on the menu, and the YSP-4000 will tweak the sound to better suit your room.

The unit also offers seven DSP modes, including three for music, three for movies, and one for sports. You can even choose a "My Beam" surround mode to direct the sound toward a specific listening position, which is really cool when you are watching movies or listening to music by your lonesome. With a built-in iPod dock, you can listen to all your digital audio tunes, which sound very good due to the YSP-4000 Compressed Music Enhancer. The Enhancer adds more depth and detail to WMA and MP3 tracks and works very well. Surround effects on movies are spatially convincing and dialogue is intelligible and clear. If you want more bass--and you will probably want more bass--you can connect an outboard subwoofer to amp up the low-frequency energy. The YSP-4000 does not have built-in decoding for the latest high-resolution formats, including Dolby TrueHD or DTS-HD Master Audio, but as far as we know, no sound bars do, so the playing field is level.

High Points
• In the market today, its hard to find a better sounding, more flexible sound bar to match your sexy new 1080p flat HDTV.
• The YSP-4000 can take the place of an entry-level receiver with its video switching capabilities and well-rounded connection set that well exceeds the input flexibility of other sound bar units.
• The YSP-4000 offers a great feature set, including an iPod dock, XM capability, IntelliBeam auto setup, HDMI upscaling, and seven DSP modes
• The YSP-4000 is perfect for the design-conscious, with a gorgeous, space-saving design

Low Points
• The remote isn't backlit, so it can be hard to use in a dark room which will draw the Eyre of any AV reviewer and consumer alike. A Harmony remote might be a good, affordable solution to control your sound bar, Blu-ray player and HDTV.
• The YSP-4000 doesn't have decoding for the latest high-resolution audio formats, Dolby TrueHD and DTS-HD Master Audio.
• There are no included S-video connections--a minor quip, considering some sound bars have no video inputs at all.
• The bass isn't devastating by any margin. I would recommend the use of a subwoofer for most applications of the YSP-4000.

Conclusion
While the Yamaha YSP-4000 is not the ultimate solution for those looking to fill a big room with bone-rattling surround sound, it is a good product for homeowners with small to medium rooms who want competent, simulated surround sound in an elegant, space-saving, unobtrusive solution. It is also a great option if you have one or two HD sources and don't really need a separate AV receiver. This is one of the best-sounding and feature-rich sound bars on the market.