While Vizio televisions have enjoyed a few years of slim, modern designs it's taken a lot longer for its A/V components to catch up. The 2015 range looks refreshingly slick however, with their black grilles and aluminum accents.
The Good
The Bad
The Bottom Line
The Vizio SB4051-C0 is the company's new penultimate sound bar and at $349 is the "cheapest" model to feature HDMI ports. The older 54-inch S5451w-C2 remains at the top of the line.
While the SB4051 offers great performance with home cinema dialogue, its sound suffers from an overly prominent subwoofer, even at the lowest volume level. Rule of thumb: if you can hear a subwoofer, it's too loud.
On the other hand, Vizio's greatest asset is its true surround-sound capability; at this price nothing else can touch it. Paired with its good looks and a stacked feature set, the SB4051 is a fine option. If only the company can fix that sub.
Design

Compared with 2013's equivalent speaker, the S4251w-B4, the SB4051-C0 is a much more aesthetically pleasing sound bar/subwoofer combo. With its aluminum caps, the Vizio has more than a passing resemblance to Definitive Technology's W Studio which is good for potential buyers but probably bad for DefTech.
While the less-expensive models in the line feature cloth grilles, the SB4051 features a fully metal design with a black powder coating.
As the name suggests, this is a 40-inch-wide 5.1 system which features discrete rear-channel speakers and a 10-inch-square subwoofer. Compared to previous 4-inch tall models, the new bar is quite squat at 3 inches and is specifically designed to fit under Vizio TVs without blocking the IR port. However, if it does happen to block your TV's remote sensor, unfortunately there's no IR blaster to pass on your instructions.
The SB4051 doesn't have a LCD display -- it's all on the remote control -- but the left side of the sound bar has a vertical row of tiny white LEDs that light up sequentially as you adjust the overall volume, center speaker, and subwoofer, or tweak the bass and treble, and so on. These indicate how high or low the settings are.
The remote control is actually quite useful. It looks like most other remotes made by the company, but the addition of that screen makes all the difference and elevates it above the competition. Changing settings is so much easier when you can actually see what parameter you're adjusting.
Features
Vizio has introduced five new sound bars this year, and most are variations on a theme: add a subwoofer here, a pair of surround speakers there. Most are based on a 38-inch sound bar, but the 40-inch version reviewed here is available only with the surround speakers and subwoofer.
Apart from an additional two inches in length over the SB3851, the 40-inch SB4051-C0 adds HDMI connectivity -- one input and one ARC-compatible output -- plus slightly better output levels.
Like any sound bar worth its salt, the Vizio offers Bluetooth with aptX compatibility for streaming from tablets and phones.
Other inputs include coaxial and optical digital, plus stereo RCA, USB and a 3.5mm auxiliary .
Unlike many competitive sound bars the Vizio features both Dolby and DTS compatibility which makes it better suited to budget home theater duties.
Setup
To start, we ran HDMI cables between our Oppo BDP-105 Blu-ray player, the SB4051 sound bar and our TV, but we had stereo sound only; the center and surround channels were missing. We spoke to Vizio and couldn't determine the cause of the problem but when we hooked an optical cable between the Oppo and the SB4051 we heard sound from all the speakers. This is how we conducted our testing.
The little wireless subwoofer linked automatically with the sound bar, but the surround speakers are wired, and they connect to the sub with RCA plugs. With this arrangement you'll probably have to put the subwoofer in the rear of the room. That's exactly what we did, with the sub to the left of the couch and the surround speakers on shelves about four feet up, on the side walls of the room.
We were a little concerned that with the sub so far away from the sound bar its bass wouldn't gel with the bar, but the blend was perfectly fine. The sub's rear room placement isn't mandatory, but that orientation keeps the surround speakers' wires in the back of the room. Alternatively, you could buy longer RCA cables and put the sub in the front of the room, and run the cables to the rear for the satellite speakers.
Once all the wires are connected, there are no setup or speaker-level calibration requirements. Using the remote you can manually adjust the subwoofer volume and that of the two surround speakers relative to the surround bar's, or simply turn the surround speakers off.
Sound quality
Wow -- the SB4051's tiny subwoofer makes a lot of bass, so much so that once we started listening with a few "Interstellar" action scenes we kept turning the sub volume level down. Even turned down all the way however, the bass could become overpowering. The sound was impressively full for such a tiny subwoofer though, and if you crave a warmly balanced, yet still crisply detailed sound, the SB4051 system could sound just right.
Most sound bars and 'bases are 2.1-channel systems, and many feature processing to simulate some semblance of surround sound. That gambit at best just produces a wider and deeper stereo soundstage. The SB4051 is a true 5.1-channel system. You don't have to be an audiophile to hear the difference the surround speakers make.
Every other 2.1-channel system -- even the most expensive Definitive Technology, Focal or Paradigm sound bars -- can't put sound behind you. Some higher-end Yamaha Sound
'bars push the sound further into the room, but they're nowhere as effective as the SB4051 in creating a total surround experience. Dialogue was clear and clean sounding.That was definitely apparent with Peter Gabriel's "New Blood, Live in London" concert Blu-ray, where the SB4051's sound leaped ahead of the pack of 2.1-channel sound bars and bases. The blend between the sound bar and surround speakers was seamless, so the concert hall ambiance sounded natural.
Surprisingly, the sub's bass didn't intrude, possibly because the bass in that concert wasn't as deep or sustained as we heard from movies. For whatever reason, the big drum and basses that start the tune "Biko" were remarkably clear and concise; Gabriel's impressively dynamic vocals weren't reined-in at all; we had to remind ourselves that this sound was coming from an affordable sound bar system.
We tried using the DTS TruVolume sound-leveling feature, which is supposed to reduce abrupt soft-to-loud volume changes, but we didn't hear much difference with it on or off.
Moving to CDs, we didn't like the sound coming from all five channels -- it was overblown and too reverberant. The fix was easy enough: we turned off the surround channels via the remote, and in stereo the SB4051 regained its composure. Recordings that didn't have a lot of bass seemed fairly well-balanced overall. Rocking out to the Black Keys "Brothers" album brought the overly bass-heavy sound roaring back. With stereo the 40-inch wide sound bar's narrow soundstage width was evident, something that's not unusual with small sound bars.
When we compared the SB4051 with last year's Vizio S5451w-C2 five-channel sound bar/separate surround speaker system, the bigger bar produced a larger sound. The S5451w-C2 has bigger speakers and a much larger wireless sub, so the bass was more powerful but better controlled; it produced tighter definition than the SB4051. That said, the older system had a softer, mellower midrange and treble balance than the SB4051.
Conclusion
The Vizio SB4051 does a lot of things right -- we loved the room-filling surround, and clear midrange and treble -- but the bass was too big and fat with some music and movies. Still, no other sound bars offer as many features for the money, so the SB4051 could be a great choice for bass lovers.