The S4251w-B4 also has built-in Bluetooth, which is pretty much a must-have feature for sound bars this year. Bluetooth is the easiest way to wirelessly stream music from the vast majority of smartphones and tablets. There is compression with Bluetooth audio, so there is some sound quality lost, but it's less noticeable from a sound bar than a system with separate speakers.
There's also onboard Dolby Digital and DTS decoding, which isn't essential on a sound bar, but can come in handy in some situations. Unfortunately most TVs "dumb down" incoming Dolby Digital and DTS (more on this later), so if you're using your TV as a switcher, you'll rarely take advantage of the built-in surround-sound decoders.
Speaker setup: Strictly DIY
Since the S4251w-B4 is technically a 5.1-channel speaker system, you might think it would include some type of automatic speaker calibration, but you're on your own in terms of adjusting levels.
It's easy enough to do by ear if you have some experience with how surround should sound, but some guidance would have been nice for home-audio neophytes. We adjusted the surround speakers' volume by ear to create a natural front-to-rear blend, and continued to fine-tune the surround speakers' volume as we watched a few movies. The S4251w-B4's tonal balance also sounded a little "thin," so we boosted the bass to +3 and lowered the treble to -1. Those settings worked well in our room, but they'll be different for everyone depending on space and preferences.
Sound quality: Real home theater sonics from a sound bar
We started our S4251w-B4 auditions with just the sound bar and subwoofer -- no surround speakers -- to get an apples-to-apples comparison with the Sony HT-CT260. The Vizio's sound was brighter and clearer than the Sony's, while also projecting a wider, better-focused, and more detailed sound stage with movies and music. The S4251w-B4's subwoofer's bass definition was also better, but the Sony's sub packed more of a wallop, with superior bass weight and oomph. We were concerned that placing the S4251w-B4's subwoofer in the back of the room would adversely affect sound quality or the blend between sub and sound bar, but it did not.
The S4251w-B4 was an adept home theater performer, handling demanding action movies with ease, although it was only average with CDs. The S4251w-B4's TruVolume mode effectively limited soft-to-loud volume changes for late-night listening sessions. Even without the surround speakers, the S4251w-B4 was mighty impressive with movies, although the 54.5-inch ultrawidesound bar was an even bigger-sounding system. The HT-SB60's richer and fuller tonal balance outclassed the S4251w-B4's sound in stereo, and the HT-SB60 could play louder without strain.
Adding the S4251w-B4's surround speakers to the system upped our estimation of its sound quality. Many sound bar speakers use processing to simulate surround effects, but even the best and most expensive ones can't match the room-filling sound of actual surround speakers. Our collection of music concert DVDs and Blu-rays sounded great over the S4251w-B4 with the surround speakers, coming closer to the sound of an AV receiver and a 5.1-channel speaker system than any other sound bar we've tested. If you're looking to simplify with a sound bar, but still preserve the surround-sound experience, the Vizio S4251w-B4 is the way to go.
But can you get true surround?
So the S4251w-B4 can create the most immersive, convincing home theater sound we've heard from a budget sound bar -- the only problem is, it's harder than you'd think to get the full effect.
If you connect all your devices directly to your TV first -- as Vizio instructs you to do -- the S4251w-B4 will likely only receive a two-channel PCM signal. That's because the vast majority of TVs "dumb down" incoming surround signals to two-channel PCM, rather than passing a true surround-sound signal. We tested several TVs in the CNET lab and only one of them (Sony's high-end XBR-55HX950) passed bona fide true Dolby Digital signal via its optical audio output.
That doesn't mean you won't hear anything in the rear speakers with the dumbed-down signal. The S4251w-B4 includes DTS Circle Surround processing, which is capable of creating a faux surround-sound mix from stereo sources. Switching between full Dolby Digital and DTS Circle-created faux surround on "Ratatouille" made it clear that there's a definite difference, with the Dolby mix sounding livelier, with a more defined surround-sound stage. But the DTS Circle mix wasn't bad, either, still creating a rainy ambiance in the opening scene with pitter-patter in the surround channels. Most listeners will likely appreciate the 360-degree sound without being too picky about the difference.
The other workaround is directly connecting devices to the sound bar using their audio outputs, rather than using your TV as as switcher. It's ultimately less convenient and you'll be limited to four devices overall. Only two of the inputs support true surround sound (optical and coaxial), and one of your devices will need a coaxial audio output, which is less common. It can work for some setups, but it's less than ideal. (Consider a universal remote to ease the pain of all the input switching.)
What are the alternatives?
The most compelling alternative to the S4251w-B4 is Sony's HT-CT260. If you don't want the extra speakers and wires of Vizio's 5.1 sound bar, the HT-CT260 is our current top choice for a traditional stereo sound bar, with solid sound quality and built-in Bluetooth for around $300. It also has a feature that passes remote signals from the front of the sound bar to the back, which helps avoid the problem of the sound bar blocking the TV's remote sensor.
Sharp's HT-SB60 is also an attractive option with even bigger sound quality from a stereo sound bar, although its extra-long sound bar won't make it a great fit for many setups. Vizio is also planning on releasing a 2.1 version of the S4251w-B4 later this year, although the release date isn't final yet.
Our other favorite sound bar is the pedestal-style, which is a much sleeker-looking option that sits under your TV, avoiding the "sound bar blocks my TV's remote sensor" issue. It also sounds great without a separate subwoofer, but its $600 price tag pushes it out of consideration for budget shoppers.
Conclusion: Unbeatable surround, if it works for you
The S4251w-B4 isn't necessarily the most accessible sound bar, as it won't work well in every living room, depending on your TV's remote sensor and whether you'll tolerate the extra speakers. But if it works for your space and you want a much more immersive sound bar experience, the Vizio S4251w-B4 sounds excellent and is a solid value at $330.