We were thrilled by Vizio’s $349.99 M51a-H6 soundbar, which provided a high-quality 5.1-channel surround sound experience in a budget-friendly chassis. Its successor, the $329.99 M-Series M51ax-J6, costs a little less and hasn’t changed much—it still has a subwoofer and dedicated rear satellites, as well as support for Dolby Atmos and DTS:X. Although we wish it had a better visual control panel, this soundbar delivers outstanding cinematic audio for the price, earning it our Editors’ Choice award for inexpensive surround sound systems.
PROS
- For a system with a subwoofer and back satellites, it’s a good value.
- With Dolby Atmos and DTS:X support, the surround imaging is excellent.
- Bass that packs a punch
CONS
- The treble isn’t as sharp as it could be.
- On the remote, there is a little visual control panel.
VIZIO M-SERIES 5.1 SOUND BAR (M51AX-J6) SPECS
Channels | 5.1 |
Bluetooth | Yes |
Wi-Fi | No |
Multi-Room | No |
Physical Connections | 3.5mm, HDMI, Optical |
Portable | No |
Water-Resistant | No |
Speakerphone | No |
Voice Assistant | None |
Simple, but useful
The main soundbar is a 36.0 by 2.2 by 3.5-inch slim, rectangular black speaker with rounded corners (HWD). Matte black plastic covers the top, back, and bottom, with square rubber pads on the bottom for support. Three front-firing 1.6-by-3.5-inch full-range drivers and three 0.8-inch tweeters are hidden under black grille fabric on the front and sides. The soundbar includes five buttons on the top panel: power, input, Bluetooth pairing, and volume up and down.
Two connecting recesses are located on the back of the soundbar. A power cable connector, as well as 3.5mm aux and aux VA ports, are located in the left recess (the latter of which is a 3.5mm input specifically for voice assistant devices with a matching output). An HDMI input, an HDMI output for eARC and visual pass-through from the input to the TV, an optical audio input, and a USB port are all located in the right recess.

The back satellites, which measure 5.7 by 2.2 by 3.5 inches apiece, resemble miniature replicas of the main soundbar. The top, bottom, and rear are all made of the same black plastic, while the front and sides have the same black grille cloth coverings. Each satellite features a square recess on the rear with an RCA port for connecting to the wireless subwoofer and a screw mount for mounting it on a stand. Although there are no clear labels on the satellites to indicate which is the left or right, the colors of the RCA ports (white or blue) match those of the subwoofer’s similar connectors (blue for left and white for right).
The subwoofer has a 5-inch downward-firing driver and an open, rear-facing bass port and measures 9.9 by 8.3 by 8.3 inches. A power cable connection, RCA ports for the satellites, and a power button are also located on the back.
In the box, Vizio includes a thin black controller. The circular navigation pad is flanked by power, input, and Bluetooth buttons, with a volume rocker, mute button, and settings buttons below. Near the top of the remote is a monochrome alphanumeric LCD that allows you to view the active input and traverse through soundbar settings one line at a time.
Unfortunately, despite its ability to connect to a TV through HDMI with eARC, the soundbar lacks an on-screen or other visual interface, so you’ll have to rely on the single-line text display on the remote to make any modifications. On the plus side, the soundbar offers speech cues to go along with your remote button presses, so you’ll know when it’s registered your requests.
Audio Performance in Music and Film
The Vizio M51ax-J6 supports Dolby Atmos and DTS:X, as previously stated. The M51ax-J6 delivers a lot of bass, which you’d expect from a speaker system with a separate subwoofer. It handled our bass test track, The Knife’s “Silent Shout,” without distortion at maximum, ear-ringing volumes, and the subwoofer produced a solid sensation of thump. The soundbar produces a surprising amount of bass response, leaving the subwoofer to produce the audible vibrations.
In its Music EQ setting, music with less deep bass, such as Yes’ “Roundabout,” displays the M51ax-overall J6’s audio balance. With a slight drop-off in treble sensitivity, it primarily favors bass and mids. The lower-frequency resonance in the opening acoustic guitar plucks is abundant, but there isn’t nearly enough high-end refinement to bring out all of the texture in the strings. The bassline shines out with the guitar strums and hi-hat piercing through the mix when the music properly kicks in, leaving the vocals to rest in the background. You may certainly get a more balanced sound by adjusting the soundbar’s bass and treble levels, but it leans low out of the box.

Through the M51ax-J6, Captain America: The Winter Soldier sounds rich and detailed, and the film’s Dolby Atmos audio is effectively reproduced. The soundbar and satellites have accurate directional imaging. However, because the three forward-facing drivers are spread across only 36 inches, the soundbar’s imaging from the front is limited. Soundbars featuring slanted drivers, such as the Sonos Arc, display a substantially larger soundstage with wider left-right panning. The Arc, on the other hand, is twice as expensive and lacks rear satellites, so it can’t deliver the same surround experience.
Regardless of the surround effect, the explosions of crashing airships have plenty of low-end response, both to the subwoofer’s rumble and the soundbar’s significantly higher, punchier bass. Against the backdrop of action and a soaring soundtrack, Captain America and Bucky’s dialogue is crystal apparent.

Zack Snyder’s Justice League is likewise powerful and theatrical, with a terrific surround sound field that surrounds the listener. The slash of swords and shrill buzzing noises abruptly punctuate the mix, while punches feel solid and impactful. Rose Betts’ wonderful voice and the modest piano backdrop in her interpretation of “Song of the Siren” come over with balance and depth in The Flash’s initial scene. The soundbar isn’t quite capable of eliciting the most subtle high-frequency characteristics in her voice, but it’s still a pleasing sound.
On a Budget: 5.1 Channels
The Vizio M51ax-J6 soundbar is a good value for money 5.1-channel home theater sound with Dolby Atmos capability. It doesn’t have the same high-frequency refinement as more expensive competitors, but it’s perfect for viewing movies and TV shows because to its rumbling bass and strong vocal performance. If you don’t need a subwoofer and want to save even more money, the Roku Streambar Pro ($179.99) provides good sound and all of the media streaming features of a Roku media center. If you really want to go all out, the JBL Bar 9.1 ($999.95) has upward-firing speakers for better directionality. The M51ax-J6, on the other hand, is hard to beat for an economical 5.1 system, earning it our Editors’ Choice award.