Most sound bars are just that: long, bar-shaped speakers you can mount (or place) below your HDTV to get better audio output than what your television's speakers can pump out. Despite what the marketing material might say, though, many can't provide true surround sound, and they can't match the performance of a dedicated home theater system. Vizio's $389.99 (direct) VHT510 Surround Sound Home Theater stands out as an exception. Thanks to a clever addition to the standard sound bar formula, the VHT510 offers true 5.1-channel sound. The sound bar itself limits the peripheral imaging of the front channels, but the rear satellites give the system a sense of depth and space other sound bars can't match.

Vizio adds two rear-channel speakers and a wireless subwoofer to the sound bar mix, giving you a full 5.1-channel sound system. The rear satellites connect to the subwoofer, which itself communicates with the sound bar with 2.4GHz radio signals that offer a maximum range of 60 feet. It's a clever way to enable rear channels without running cables from the sound bar/receiver/home theater components across the length of the room.

Design
The main sound bar measures 4.5 by 40 by 4.3 inches (HWD) and weighs 7.8 pounds, making it ideal for HDTVs between 38 and 42 inches. It can work just fine with larger sets, but its length is matched with screens in the 40-inch range. The subwoofer measures 13 by 11.2 by 11.9 inches and weighs nearly twice as much as the sound bar at 14.6 pounds. The two satellites measure a modest 7.5 by 2.9 by 11.9 inches and weigh 1.6 pounds each. Multiple screw and hook mounting holes make the speakers easy to mount on the wall or stands, and the metal feet on the sound bar can be rotated around and turned into mounting hardware with a twist of two screws.

A soft black grille covers the front of the sound bar, hiding its two 3-inch and two 2.75-inch drivers. Its two 0.75-inch tweeters sit, uncovered by the cloth grill but protected by a circular metal grill, on either end of the bar, and a metal rectangle with the Vizio logo and a few indicator lights sit in the center of the bar. These lights aren't the most important lights on the sound bar, however; a row of blue LEDs hidden behind the grille, under the metal rectangle, serve as a main display, lighting up to show volume and balance levels and input modes. The satellites and subwoofer share a similar design with the sound bar: vertically standing semi-cylinders with soft black grilles and, in the case of the satellites, the same hard-grilled 0.75-inch tweeters.

The back of the sound bar features optical and stereo RCA audio inputs, plus the power plug connector, and a switch to set client/hub mode for using the sound bar with multiple subwoofers or other wireless audio devices. It lacks a 3.5-mm auxiliary input, meaning unless you specifically buy the iPod accessory dock, you can't simply plug your iPod or smartphone into the system. The Insignia NS-BAR-A Home Theater Soundbar ($199.99, 2.5 stars) costs slightly more than half as much as the VHT510 and it has a 3.5-mm input, though it lacks the wireless subwoofer and rear channel satellites. For a ton of input options at a premium price, the Samsung HT-D550 ($499.99, 4 stars) can accept two HDMI connections (through mini-HDMI), two optical audio connections, and a 3.5-mm analog audio connection, and it can serve as a video passthrough to your HDTV via HDMI, making it useful as a simple A/V receiver/switch. While the HT-D550 includes a wireless subwoofer, it doesn't come with the dedicated rear-channel satellites.

The bundled 4.4-inch-long, 2-inch-wide remote control is rounded and easy to grab, and includes Power, Mute, Volume, and Play/Reverse/Fast Forward Playback controls. But a hidden slide-down panel exposes more advanced controls, including input selection between stereo line-in, optical audio, and iPod, SRS TruVolume and SRS StudioSound toggles, and individual volume/equalizer controls for the subwoofer, bass, treble, center, and rear channels. It's a smart design, but it would be even more useful with the input selection buttons on the main panel of the remote and not hidden. Of course, the iPod input is effectively the same as the stereo line-in input with an optional dock, and for most home theater uses you're going to keep the system set to optical-in from the HDTV, so it's not a major issue.

Performance
While it doesn't deliver the kick of a home theater with large, dedicated left/right/center satellites, the VHT510 performed well in our lab tests. Thanks to the subwoofer and rear satellites, the system offered both satisfying bass response and genuine surround sound, features most sound bars lack. I loaded Robocop from the Robocop Trilogy Blu-ray box set and watched several violent scenes. Dialog sounded clear, music swelled adequately, and explosions got a good amount of boost from the subwoofer, giving them a feeling of depth and impact. During the gunfight in the drug factory, all of the action sounded satisfying, and the rear satellites projected fantastic pistol shots and ricochets, giving the entire scene an immersive feel usually only heard with true 5.1-channel sound systems.

To test low end, I played our test-suite standby, The Knife's bass-heavy "Silent Shout." The thumping bass popped thanks to the subwoofer, sending out the booming synth noise all the way across the lab, through the doors of our closed home theater test area. The sound bar itself didn't fare quite as well, distorting and sounding hollow; the crossover point between the sound bar and the subwoofer seemed to be set too low, so the bar tried to reach into the high end of the low frequencies for which the subwoofer was best suited. Still, putting out that much power is impressive, and when the melody kicked in, both the sound bar and satellites chimed in as well.

The sound system isn't perfect, though. Since the main component is a 40-inch sound bar that handles the left, center, and right channels, its front imaging is limited. While it's great for 40-inch HDTVs, if you have a very large home theater the sense of space produced by the sound bar will feel more narrow than the picture on your screen. Its satellites also feel a bit underpowered, handling the high frequencies great but lacking the mid-range punch the main sound bar produces.

Among the current crop of sound bar sound systems, Vizio's VHT510 stands as one of only a few that offers real surround sound and not merely acoustic reflection. At less than $400, that alone makes it a compelling choice, improved by the fact that it sounds great and is easy to set up, but if you're willing to sacrifice dedicated rear channels for a smaller, lighter, more attractive sound bar, you might want to consider the Samsung HT-D550. At $500, the Samsung system will cost you more, and doesn't have a true pair of rear channels, but it's a glossier, thinner device that still produces solid audio and can serve as a two-device A/V receiver/switch.