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Vizio SB4551-D5 review: Sound bar with flat subwoofer makes sweet, discreet bombast

The Vizio SB4551 sound bar offers an enveloping experience with movies that competitors can't touch while also including some tasty streaming features.

Ty Pendlebury Editor
Ty Pendlebury has worked at CNET since 2006. He lives in New York City where he writes about streaming and home audio.
Expertise Ty has worked for radio, print, and online publications, and has been writing about home entertainment since 2004. He is an avid record collector and streaming music enthusiast. Credentials
  • Ty was nominated for Best New Journalist at the Australian IT Journalism awards, but he has only ever won one thing. As a youth, he was awarded a free session for the photography studio at a local supermarket.
Steve Guttenberg
Ex-movie theater projectionist Steve Guttenberg has also worked as a high-end audio salesman, and as a record producer. Steve currently reviews audio products for CNET and works as a freelance writer for Stereophile.
Ty Pendlebury
Steve Guttenberg
5 min read

Speakers are often designed to appeal more to the eye than to the ear. That's why many modern sound bars are incredibly small -- barely an inch tall. They still sound better than the speakers in your TV, however, and the best can pack a full-sounding punch thanks to separate subwoofers you can stash in a discreet location.


Vizio SB4551-D5

The Good

The Vizio SB4551 belts out top-notch home theater sound for the price. The unique, flat-as-a-pancake subwoofer easily slides under your sofa and the wired surround speakers add immersion. The sound bar offers a wealth of connectivity in addition to Google Cast multi-room functionality.

The Bad

The Vizio's display is a series of dots that are hard to decipher. Music replay isn't the equal of some rivals. Google Cast is still not as reliable or as fun as a Sonos or Play-Fi system if you're looking to do multi-room music.

The Bottom Line

The Vizio SB4551 sound bar offers an enveloping experience with movies that competitors can't touch, while also including some tasty streaming features.

At the high-end you have brands such as Definitive Technology and Bose, while at the more affordable end you have LG and Vizio. We were quite impressed with the features and sound of the $400 LG SH7B, but the Korean company's peaceful idyll is about to be disturbed by Chinese-American Vizio.

Despite a few usability quirks and an awkward name, the $500 Vizio SB4551-D5 is one of the best sound bars you can buy for home theater. It includes actual surround speakers -- yes they're wired and not wireless, but they still create an immersive soundstage that bar-only systems can't match -- and one of the most discreet subwoofers we've seen. These components help create superb sound for the money, and Google Cast is just icing on the flat cake.



The Vizio SB4551-D5 is one of the best sound bars you can buy for home theater.

Sarah Tew/CNET

The key to the sound bar's size lies in that awkward name. This is a 45-inch wide sound bar that measures 2-inches high and deep. Vizio has again taken design cues from Definitive Technology, aping the faux aluminum endcaps and black steel mesh.


Controls on the sound bar.

Sarah Tew/CNET

At the top of the main speaker lies a line of controls including input selection, Bluetooth pairing and volume. Unfortunately the front display is just an inscrutable series of small dots, and there is no on-screen display that can appear on your TV. The LG SH7B one-ups the Vizio with its large, easy-to-read alphanumeric readout. In its favor, Vizio's well-designed remote does display the input and other pertinent information.


The subwoofer is in this box.

Sarah Tew/CNET

That big flat box contains an 8-inch subwoofer. Just 3.5 inches tall, it's slim enough to be stashed underneath the couch, and comes with a pair of feet which enable it to stand on-end. As before the rear satellite speakers connect via really long cables to the subwoofer.


The remote for the sound bar.

Sarah Tew/CNET


For the Vizio's $500 asking price most companies will only sell you a 2.1-channel sound bar sans satellite speakers, and any "wide" mode it uses to fake surround sound will seldom be convincing. The SB4551's included rear speakers really kick up the immersion a notch.


The included rear speakers help bring out more sound from your movies.

Sarah Tew/CNET

The SB4551 offers plenty of inputs which include HDMI in and out, coaxial and optical digital, 3.5mm analog, USB, Bluetooth and 802.11n wireless. The sound bar also comes with an Ethernet port, but if you follow the setup routine the Vizio will blithely ignore it and urge you to use Wi-Fi anyway.

Sarah Tew/CNET

Unlike some sound bars the Vizio will decode DTS and Dolby Digital.


Sarah Tew/CNET

Vizio introduced its SmartCast system with the release of its 2016 TV range, and now the feature extends to the company's sound bars and smart speakers. SmartCast is essentially a supercharged version of Google Cast with some extra Vizio functionality thrown in.

Music apps like Pandora and Spotify that work with Chromecast will also "see" the Vizio sound bar when you tap the little Cast icon. Doing so allows you to control playback through the 'bar using your phone.

Vizio's SmartCast app for iOS and Android can control the bar's settings, and also enables you to set up a multi-room system using other Vizio components, a Chromecast Audio, or other Google Cast-compatible products from the likes of LG, Sony, Raumfeld and Polk.


The Vizio SB4551's setup is a bit more complicated than the average sound bar because you also have to hook up wired surround speakers to the SB4551's flat subwoofer. You can adjust the SB4551's bass, treble, subwoofer volume, along with surround speaker on/off and their balance levels by toggling through the LCD menu on the remote, or the SmartCast app. As soon as we started listening the SB4551 sounded balanced, we felt no further need to fuss with the setup.

While Google recommends using its Google Cast application to set up compatible components, it failed to recognize the Vizio sound bar. Instead, the SmartCast application was able to guide us through the process of setting up the unit and connecting it to our network (and to a Chromecast Audio).


The ultra skinny SB4551 sound bar and flat subwoofer together produced uninhibited home theater bombast with the "Master & Commander" Blu-ray's naval battle scenes. The fearsome cannon ball exchanges between mighty wooden ships have humbled many a sound bar system in the CNET listening room, rendering them weak or distorted, but the SB4551 never faltered. Even with the volume turned up the SB4551's home theater muscle stayed the course. The skinny sub defied our expectations, bass was deep and clearly defined, without a hint of muddiness or thickening.

The sound bar projected a wide stereo soundstage, and the surround speakers created an immersive room filling sound that even significantly more expensive stereo-only sound bars could never match. Dialog remained clear and articulate in the midst of heavy duty battle scenes.

During the gruesome scenes where a grizzly bear attacks Hugh Glass (Leonardo DiCaprio) in "The Revenant," the SB4551 provided a far more visceral experience than the LG SH7B sound bar. Right away we noted the SB4551 could play louder and with more low bass oomph than the SH7B. Not only that, the SB4551's front soundstage was broader and deeper than the SH7B's.

Positioned directly behind our listening chair Vizio's subwoofer blended well enough with the sound bar while watching movies, but the blend worsened with music. Moving the sub to a position right next to the sound bar produced a more seamless blend. Even so, music sounded fuller and more natural over the LG SH7B, its treble softer and more laid-back. The Vizio SB4551, while very clear, sounded a tad lean in comparison.

When it comes to multi-room music, if you set your expectations low the SB4551 will do most of the things you want. We were able to cast to the sound bar and a Chromecast Audio simultaneously from a single app on our phone, and the two kept in perfect sync. Apps such as Toaster Cast (for streaming from a network storage device) and Tidal worked very well.

On the other hand Vizio/Google's system isn't as robust as Sonos or even Play-Fi. The sound bar would sometimes disappear from the list of castable speakers, or the sound would cut out if we switched between apps. The Vizio wasn't able to decode any of the hi-res material that we use as reference, something that the Chromecast Audio can do. Based on these first tastes of multi-brand, multi-room Google Cast, we feel that more needs to be done before it can challenge the multi-room leaders.


Don't let the Vizio SB4551's sleek design fool you, this system has the guts to rattle your living room. We especially appreciated what the surround speakers can bring to the experience: they create a far more enveloping sound than stereo bar/subwoofer systems can muster. True, the surround speakers have wires, which might be a deal breaker for some prospective buyers, but the sound benefits of surround speakers should not be ignored.

The only negative point, apart from some usability headaches, was that the SB4551's talents fell short with music. As usual, if music is your priority, buy a receiver and dedicated speakers instead of a sound bar.


Vizio SB4551-D5

Score Breakdown

Design 8Features 10Sound 8Value 8