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Vizio M Series M51a-H6 Soundbar Review

Tested using Methodology v1.3
Reviewed Mar 11, 2021 at 08:33 am
Latest change: Writing modified Sep 04, 2024 at 04:43 pm
Vizio M Series M51a-H6 Picture
8.0
Mixed Usage
8.3
Dialogue/TV Shows
7.7
Music
7.9
Movies
This soundbar was replaced by the Vizio M Series M51ax-J6

The Vizio M Series M51a-H6 is a 5.1 setup from 2020. It's currently available from Costco and the manufacturer's website. This soundbar has a really neutral, balanced sound profile out-of-the-box, and its dedicated subwoofer helps to add a little extra kick in the bass range. There are even a few EQ presets to help you customize its sound to your liking. It also offers a great surround performance thanks to its dedicated satellites. While it supports Dolby Atmos content, its performance isn't the most impressive.

Our Verdict

8.0 Mixed Usage

The Vizio M51a-H6 is impressive for mixed usage. Out-of-the-box, it has a very neutral sound profile that's suitable for listening to lots of different types of audio content. Its dedicated subwoofer adds a little extra kick in the bass range that's ideal for watching action-packed movies or listening to bass-heavy music. It comes with dedicated surround speakers, and while it supports Atmos content, it doesn't provide the most immersive listening experience.

Pros
  • Supports Atmos content.
  • Gets loud.
  • EQ presets.
Cons
  • Middling height performance.
  • No graphic EQ.
8.3 Dialogue/TV Shows

The Vizio M51a-H6 is impressive for dialogue-centric content like TV shows. Thanks to its dedicated center channel and balanced mid-range, voices are reproduced clearly and accurately. There's even a dialogue enhancement feature to make voices sound more crisp, and it gets pretty loud, too. You can also wirelessly stream podcasts from your phone to the bar via Bluetooth, but unfortunately, it doesn't support Wi-Fi.

Pros
  • Gets loud.
  • Dialogue enhancement feature.
  • EQ presets.
Cons
  • Only supports Bluetooth wireless.
7.7 Music

The Vizio M51a-H6 is good for music. Its neutral sound profile is suitable for listening to many different genres, and there's even a little extra kick in the bass that can please fans of bass-heavy music like EDM. A few EQ presets and bass and treble adjustments are there to help you customize its sound, too. Unfortunately, it lacks a more comprehensive graphic EQ.

Pros
  • Gets loud.
  • EQ presets.
Cons
  • No graphic EQ.
7.9 Movies

The Vizio M51a-H6 is very good for movies. It has a balanced, neutral sound profile with a little extra kick in the bass that's ideal for watching action-packed scenes. It comes with dedicated surround speakers, and it gets pretty loud, which is handy. While it can play Atmos content thanks to its front-firing speakers, it doesn't have a very impressive performance.

Pros
  • Supports Atmos content.
  • Gets loud.
  • Dialogue enhancement feature.
Cons
  • Middling height performance.
  • 8.0 Mixed Usage
  • 8.3 Dialogue/TV Shows
  • 7.7 Music
  • 7.9 Movies
  1. Updated Sep 04, 2024: Updated the Stereo Dynamics, Stereo Frequency Response With Preliminary Calibrations, and Surround 5.1 results with new methodology from Test Bench 1.3 and accompanying text. Added text to Audio Latency: ARC, Audio Latency: HDMI In, and Audio Latency: Optical boxes.
  2. Updated Aug 28, 2024: We've converted this review to Test Bench Update 1.3. If applicable, we've retested stereo sound based on the manufacturer's recommendations. Additionally, we've expanded our audio latency tests to the following boxes: Audio Latency: ARC, Audio Latency: HDMI In, and Audio Latency: Optical. You can see the full changelog here.
  3. Updated May 05, 2023: Converted to Test Bench 1.2. Updated the results for audio format support via ARC/eARC, HDMI In, and Optical. Added Video Passthrough to TV results as well.
  4. Updated Mar 20, 2023: Added cable lengths to In The Box.
  5. Updated Mar 16, 2023: Converted to Test Bench 1.1. With this update, we've added a Mounting test and added information aboutSubwoofer Output, Spotify Connect, and Microphone Mute.
  6. Updated Nov 24, 2022: Added the Samsung HW-Q67CB as a market comparison to theHeight (Atmos) box.
  7. Updated Sep 27, 2022: Added market comparison for the Vizio M Series M213ad-K8 to the 'Style - Satellites' box.
  8. Updated Sep 22, 2022: After reviewing the Vizio M Series M215a-J6, added a market comparison to 'Style - Satellites' box.
  9. Updated Mar 11, 2021: Review published.
  10. Updated Mar 08, 2021: Early access published.
  11. Updated Mar 01, 2021: Our testers have started testing this product.
  12. Updated Feb 26, 2021: The product has arrived in our lab, and our testers will start evaluating it soon.
  13. Updated Feb 21, 2021: We've purchased the product and are waiting for it to arrive in our lab.

Differences Between Sizes And Variants

The Vizio M51a-H6 is available in 'Black', and you can see the label for the model we tested here.

If you come across another version, let us know in the discussions so we can update our review.

Compared To Other Soundbars

The Vizio M51a-H6 is a 5.1 setup from 2020 that offers very versatile performance for a budget-level price. It has a balanced sound profile out-of-the-box with an extended low-bass, and its dedicated satellites offer a good surrounds performance. While it supports Dolby Atmos content, it doesn't offer a very immersive listening experience.

See also our recommendations for the best soundbars, the best soundbars under $500, and the best Vizio soundbars.

Vizio M Series M51ax-J6

The Vizio M Series M51a-H6 is a better soundbar for mixed usage than the Vizio M Series M51ax-J6. The M51a-H6 offers a better latency performance over its ARC port, though HDMI In has higher latency. It also reproduces a more extended low bass to help you feel thump and rumble.

Vizio V Series V51-H6

The Vizio M Series M51a-H6 is a better soundbar than the Vizio V Series V51-H6. The M Series has a more neutral sound profile out of the box and a better surround performance. It also supports Dolby Atmos content, and because it has a Full HDMI In port, it can support 4k passthrough.

Vizio M Series M512a-H6

The Vizio M Series M51a-H6 is better than the Vizio M Series M512a-H6, though it depends on the kinds of audio you listen to. The M51a-H6 has a better surround sound and lower latency. However, the M512a-H6 is better built and has a better soundstage performance with slightly better passthrough capabilities. It also comes with two up-firing speakers.

Sonos Arc

The Vizio M Series M51a-H6 is a better soundbar than the standalone Sonos Arc. The Vizio gets louder with less compression at max volume, and it has a more extended low bass thanks to its dedicated subwoofer. Its satellites help create a more immersive surround experience. It also offers some EQ presets and a Full HDMI In port. However, the Sonos is better built with a better soundstage performance and a room correction feature. You may also want to compare this bar with the Sonos Arc with Sub + One SL Speakers.

JBL Bar 9.1

Depending on your uses, the Vizio M Series M51a-H6 is better than the JBL Bar 9.1. The Vizio reproduces a more extended low bass, so you feel more thump and rumble in your audio. It gets louder, and it has a dialogue enhancement feature. However, the JBL is better-built and has more wireless playback options. It has a better soundstage, slightly better Dolby Atmos and surround sound performance, and a room correction feature, but it has worse passthrough compatibility.

Vizio M Series M215a-J6

The Vizio M Series M51a-H6 is a 5.1 soundbar that offers better overall performance than the 2.1 Vizio M Series M215a-J6. The 5.1 option has two rear satellites, dramatically improving its performance with Atmos and surround sound. Its discrete center channel means that it has greater vocal clarity, too. The 2.1 is a fair option if you just listen to stereo content, like most music, as it's a more affordable choice. That said, the 5.1 Vizio performs better overall.

Vizio V Series V51x-J6

The Vizio M Series M51a-H6 is a better soundbar than the Vizio V Series V51x-J6. The M Series supports Dolby Atmos content and offers better surround performance. It also reproduces a more even midrange. Unlike the V Series, it has a Full HDMI In port supporting high-quality passthrough. However, only the V Series has an AUX In port for voice assistant-enabled devices.

Vizio Elevate

The Vizio Elevate and the Vizio M Series M51a-H6 are both very versatile soundbars; depending on your listening habits, you may prefer one over the other. The Elevate has a unique design with sides that rotate upwards to create a more immersive listening experience. It's better built, has a better stereo soundstage performance, and supports Wi-Fi and Chromecast built-in. However, the M Series has better surround performance, center channel accuracy, and lower latency.

Vizio SB46514-F6

Depending on your usage, the Vizio M Series M51a-H6 might be better than the Vizio SB46514-F6. The M51a-H6 has more sound enhancement features, including dialogue enhancement. It also has more extended low bass and a better center performance. However, the SB46514-F6 has a better Atmos performance and similar surround sound performance. It's also better built and has more wireless playback options.

Sonos Beam (Gen 2)

The Vizio M Series M51a-H6 is better than the Sonos Beam (Gen 2). The Vizio is a 5.1 setup with a dedicated sub and satellites. It can get louder and has better surround performance. Unlike the Sonos, it even has a Full HDMI In port for high-quality passthrough. However, the standalone 5.0 Sonos is still a solid choice for users who want a more compact bar. It's better built, has a better soundstage, and has built-in voice assistant capabilities.

Samsung HW-Q67CB

The Vizio M Series M51a-H6 is better than the Samsung HW-Q67CB. They're both 5.1 soundbars with Dolby Atmos support. However, the Vizio can reproduce a more extended low bass, so you can feel more thump and rumble in the mix. The Vizio also offers less compression at max volume, letting you enjoy a clearer sound at louder volumes. It doesn't have a graphic EQ like the Samsung, but its bass and treble adjustments will be enough for most uses.

Samsung HW-Q65T

The Vizio M Series M51a-H6 is a better soundbar than the Samsung HW-Q65T. The Vizio has a more extended low bass and a more neutral sound profile out of the box. It also supports Dolby Atmos content. However, the Samsung is better built and has a graphic EQ for sound customization.

Vizio SB36512-F6

The Vizio M Series M51a-H6 is a better soundbar than the Vizio SB36512-F6. The M Series has a more neutral sound profile out of the box and can get louder. It has a better surround performance and more sound enhancement features and supports DTS:X. However, the SB36512-F6 is Wi-Fi compatible and has Chromecast built-in.

Sonos Beam

The Vizio M Series M51a-H6 is better than the Sonos Beam. The Vizio is a 5.1 setup with a dedicated sub that helps reproduce a more extended low bass. Thanks to its satellites, it also has a better surround performance. Unlike the Sonos, it supports Atmos content and comes with EQ presets and a Full HDMI In port. However, some listeners may prefer the Sonos' better-built, more compact design. Unlike the Vizio, the Sonos has room correction and built-in voice assistant support. Its stereo soundstage performance is better, too.

JBL Bar 5.1 Surround

The Vizio M Series M51a-H6 is better than the JBL Bar 5.1 Surround. The Vizio comes with dedicated satellites and supports Dolby Atmos content. It gets louder with less compression at max volume and has better soundstage and surround performances. That said, the JBL is better built and has more wireless playback options.

Vizio SB36312-G6

The Vizio M Series M51a-H6 is better than the Vizio SB36312-G6. The M Series is a 5.1 setup that comes with dedicated satellite speakers. It offers better surround and Atmos performances, and it can get louder. Also, some users may prefer its more neutral sound profile out-of-the-box. That said, the SB36312-G6 does support more wireless playback options.

Vizio SB2020n-J6

The Vizio M Series M51a-H6 is better than the Vizio SB2020n-J6. They're two very different setups, and the M51a-H6 comes with a dedicated subwoofer and satellites. It can reproduce a more extended low bass. While the SB2020n-J6 only supports PCM content, the M51a-H6 supports surround sound like Dolby Digital and DTS, as well as Dolby Atmos content. However, if you want a budget-friendly model for dialogue-centric content like TV shows, the SB2020n-J6 is an okay choice.

Klipsch Cinema 600

The Vizio M Series M51a-H6 is better than the Klipsch Cinema 600. The Vizio is a better-built 5.1 setup with discrete satellites. It has better soundstage, center, and surround performances. Unlike the Klipsch, it also supports Dolby Atmos content. There are also more sound enhancement features available, including EQ presets.

Klipsch Cinema 800

The Vizio M Series M51a-H6 is better for mixed usage than the Klipsch Cinema 800. The Vizio is a better-built 5.1 setup with discrete satellites. It has better surround and Atmos performances. Unlike the Klipsch, it supports DTS content. However, the 3.1 Klipsch has a better soundstage. It can also reproduce a more extended low bass.

Samsung HW-Q59CT

The Vizio M Series M51a-H6 is better than the Samsung HW-Q59CT. The Vizio comes with discrete satellite speakers, and unlike the Samsung soundbar, it supports Dolby Atmos content. It also offers a better surround performance and can reproduce a more extended low bass. That said, the Samsung is better built, and some listeners may prefer its graphic EQ for sound customization over the Vizio's bass and treble adjustments.

Samsung HW-Q700A

The Vizio M Series M51a-H6 is better than the Samsung HW-Q700A. The Vizio is a 5.1 setup with discrete satellite speakers. It offers better surround performance and can reproduce a more extended low bass. It also gets louder with less compression at max volume. That said, the 3.1.2 Samsung is better built. It also has a better soundstage and a graphic EQ.

Samsung HW-Q950A

The Samsung HW-Q950A is better than the Vizio M Series M51a-H6. The Samsung is an 11.1.4 setup that's better built and gets louder. It has better soundstage, surround, and Atmos performances, too. There are also more sound enhancement features, like room correction and a graphic EQ. It supports more wireless playback options than the Vizio and has built-in voice assistant support.

Samsung HW-Q850A

The Samsung HW-Q850A and the Vizio M Series M51a-H6 are both versatile 5.1 setups, but the Vizio scores better overall. The Vizio gets louder with less compression at max volume and has a better center channel performance. It can reproduce a more extended low bass; some users may prefer its more neutral sound out-of-the-box. That said, the better-built Samsung has better soundstage and surround performances. Unlike the Vizio, it also has built-in voice assistant capabilities.

Samsung HW-A650

The Vizio M Series M51a-H6 is better than the Samsung HW-A650. The Vizio is a 5.1 setup that supports Dolby Atmos content and comes with discrete satellites, unlike the Samsung soundbar. It also reproduces a more extended low bass and has a better surround performance. However, the 3.1 Samsung is better built, and some users may prefer its graphic EQ for sound customization.

Samsung HW-Q600A

The Vizio M Series M51a-H6 is better than the Samsung HW-Q600A. The Vizio is a 5.1 setup that comes with discrete satellite speakers and offers better surround and Atmos performances. It also reproduces a more extended low bass, so you feel more thump and rumble in your audio. That said, the Samsung is better built. Unlike the Vizio, it has a graphic EQ to help you customize its sound.

Samsung HW-A550

The Vizio M Series M51a-H6 is better than the Samsung HW-A550. The Vizio is a 5.1 setup with discrete satellites that offers better center and surround performances. Unlike the Samsung, it supports Dolby Atmos content, too. It can even reproduce a more extended low bass. That said, the 2.1 Samsung is better built.

Samsung HW-Q800A

Depending on your listening habits, you may prefer either the Vizio M Series M51a-H6 or the Samsung HW-Q800A. The Samsung is a better-built 3.1.2 setup with more wireless playback options and a more neutral stereo sound. It also comes with a graphic EQ to help you customize its sound. However, the 5.1 Vizio has discrete satellites and offers better surround and Dolby Atmos performance.

Samsung HW-Q60T

The Vizio M Series M51a-H6 is a better 5.1 setup than the Samsung HW-Q60T. The Vizio comes with discrete satellites, and unlike the Samsung, it supports Dolby Atmos content. It has better surround performance and can even reproduce a more extended low bass. That said, the Samsung is better built.

Sonos Arc with Sub + One SL Speakers

The Sonos Arc with Sub + One SL Speakers is better than the Vizio M Series M51a-H6 for most uses. The Sonos is better built, with better soundstage, surround, and Atmos performances. Unlike the Vizio, it has room correction and built-in voice assistant support. Some listeners may prefer the Vizio's more neutral sound profile out-of-the-box. The Vizio also has a Full HDMI In port that supports high-quality passthrough, unlike the Sonos.

Samsung HW-T650

The Vizio M Series M51a-H6 is a better soundbar than the Samsung HW-T650. The Vizio is a 5.1 setup with a better surround performance that also supports Atmos and DTS:X content. It has a more extended low bass, and it can support 4k passthrough. However, the Samsung is better built and offers a better stereo soundstage performance.

Samsung HW-Q70T

The Vizio M Series M51a-H6 is better than the Samsung HW-Q70T. The Vizio is a 5.1 setup with discrete satellites. It has better surround and Atmos performances. Also, it can reproduce a more extended low bass. That said, the 3.1.2 Samsung is better built and has more wireless playback options.

Vizio M Series M21d-H8R

The Vizio M Series M51a-H6 is better than the Vizio M-Series M21d-H8R. The M51a-H6 is a 5.1 setup with a dedicated sub and two satellite speakers. It has better soundstage, center, and surround performances and supports Atmos content. It also gets louder with much less compression at max volume. However, the 2.1 M21d-H8R is better built.

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Test Results

perceptual testing image
Design
Design
Style - Bar

The Vizio M51a-H6 is a simple, all-black soundbar. It's mostly made of plastic with a thin fabric covering the front and the sides.

Design
Style - Subwoofer
Sub Wireless
Yes
Enclosure
Ported

The sub sits on four plastic pegs that have rubber grips. It's mostly made of plastic. The port is located on the back of the sub, and the speaker is located underneath.

Design
Style - Satellites
Satellite Wireless
Partial, wired to wireless sub

This soundbar comes with two satellite speakers that have a similar design to the bar. They're mostly made of plastic with fabric covering the front and the sides. If you don't have room for satellites, but want a similar bar with Atmos capabilities, check out the Vizio M Series M215a-J6 or the Vizio M Series M213ad-K8.

Design
Dimensions - Bar
Width 36.0" (91.5 cm)
Height 2.3" (5.8 cm)
Depth 3.5" (9.0 cm)

The Vizio M51a-H6 isn't very wide, but it likely won't fit between the legs of a 55" TV. However, it isn't very tall, so it shouldn't block your TV screen unless your TV sits flush on the table.

Design
Dimensions - Subwoofer
Width 8.3" (21.2 cm)
Height 9.9" (25.2 cm)
Depth 11.7" (29.7 cm)

The subwoofer is roughly the same size as the subwoofer for the Vizio V Series V51-H6, though it's deeper. It's a bit shorter than the average desktop PC.

Design
Dimensions - Satellites
Width 5.7" (14.6 cm)
Height 2.3" (5.8 cm)
Depth 3.5" (9.0 cm)

The satellites are fairly small. They don't need a power cable to operate, but you need to wire them to the subwoofer to get them to work.

Design
Mounting
Mountable Bar
Yes
Bar Brackets Included
Yes
Mountable Satellites
Yes
Satellite Brackets Included
Yes
7.0
Design
Build Quality

The Vizio M51a-H6 has a decent build quality. The bar and the satellites are mostly made of matte plastic, which feels quite solid. However, the fabric covering the front and the sides seems like it could rip or get dirty easily. The subwoofer is also made of plastic. For a better-built soundbar, check out the Samsung HW-Q65T or the Vizio M Series M512a-H6.

Design
In The Box

  • 2x power cables (8.5 ft / 2.6m and 4.9 ft / 1.5m)
  • 3.5mm to 3.5mm audio cable (4.9 ft / 1.5m)
  • Stereo RCA to 3.5mm audio cable (4.9 ft / 1.5m)
  • 2x Surround Speaker audio cables (26 ft / 8.0m)
  • Optical cable (4.9 ft / 1.5m)
  • HDMI cable (6.2 ft / 1.9m)
  • 4x Cable ties
  • Remote with batteries (2x AAA)
  • Wall Mount template
  • 4x Wall Mount brackets
  • 4x Wall Mount screws
  • User Manual

Sound
8.0
Sound
Stereo Frequency Response
Channels
5.1
Tested Preset
Direct
Slope
-0.46
Standard Error
3.35 dB
Low-Frequency Extension
31.3 Hz
High-Frequency Extension
19.9 kHz

Out-of-the-box, the Vizio M51a-H6 has an excellent stereo frequency response. It has a very neutral sound profile, suitable for listening to lots of different types of audio content. There's a little extra boom in the bass range that can please fans of bass-heavy music like EDM and hip-hop, too.

8.0
Sound
Stereo Frequency Response With Preliminary Calibration
Suggested Preset
Direct
Suggested Bass Setting
-5
Suggested Treble Setting
1
Slope
-0.20
Standard Error
3.29 dB
Low-Frequency Extension
30.8 Hz
High-Frequency Extension
19.9 kHz

The Vizio M51a-H6 comes with bass and treble adjustments, as well as EQ presets to help you customize its sound profile. While we tested the bar in several different configurations, we found that adjusting bass to '-5' and increasing treble to '1' offers the most neutral response.

7.0
Sound
Stereo Soundstage
Crosstalk Error
2.47 dB

The Vizio M Series 5.1 Soundbar has a decent stereo soundstage performance. The soundstage is perceived to be a little wider than the bar itself, but it doesn't have any tricks to make it sound wider than that. It has good focus, though, so objects in the soundstage seem to come from an accurate location rather than a general area.

8.4
Sound
Stereo Dynamics
SPL @ Max Volume
96.0 dB SPL
DRC @ 90dB
0.23 dB
DRC @ Max Volume
1.94 dB

The Vizio M51a-H6 has impressive stereo dynamics. It gets pretty loud, and there isn't a lot of compression at max volume, so it's a solid choice for listening to music at crowded parties or in large rooms.

8.4
Sound
Center
Localization
Discrete
Slope
-0.17
Std. Err.
2.85 dB
SPL @ Max Volume
93.5 dB SPL
Weighted THD @ 80dB
0.74
Weighted THD @ Max Volume
1.68

The Vizio M51a-H6 is a 5.1 setup with great center channel performance. Due to its configuration, it has a dedicated center speaker that reproduces dialogue more clearly and accurately. It can also get pretty loud.

7.5
Sound
Surround 5.1
Localization
Discrete
Slope
-0.10
Std. Err.
4.15 dB
SPL @ Max Volume
94.7 dB SPL
Weighted THD @ 80dB
0.32
Weighted THD @ Max Volume
1.06
7.1 Rears
No

The Vizio M51a-H6 has a good surround performance. Its discrete surround speakers help to clearly and accurately represent objects like voices and footsteps in the surround stage. Its sound profile is also pretty neutral, though slightly bass-heavy, so audio content packs a little extra thump and punch, while the top end has veiled detail.

5.9
Sound
Height (Atmos)
Localization
Phantom (Front Firing, Satellites)
Slope
-0.03
Std. Err.
4.06 dB
SPL @ Max Volume
86.9 dB SPL
Weighted THD @ 80dB
2.29
Weighted THD @ Max Volume
0.33

The Vizio M51a-H6 has a middling Atmos performance. Unlike the Vizio V Series V51x-J6, it uses front-firing speakers on its satellites to ricochet sound off the ceiling and back down to you to help create the illusion of height. It brings more rumble in the low bass than similar 5.1 Atmos setups like the Samsung HW-Q67CB, which is great for bringing action-packed scenes to life. However, it doesn't sound as real as dedicated down-firing speakers in a home theater setup.

7.1
Sound
Sound Enhancement Features
Room Correction
No
Dialogue Enhancement
Yes
Auto-Volume/Night Mode
Yes
Subwoofer Level Adjustment
Yes
Bass Adjustment
Yes
Treble Adjustment
Yes
EQ
Presets
Surround Level Adjustment
Yes
Rear Level Adjustment
No
Height Level Adjustment
No
Virtual Surround
Yes

The Vizio M51a-H6 has a decent selection of sound enhancement features. There are four EQ presets to help you customize its sound, including 'Movie', 'Music', 'Direct', and 'Game'. There's also a dialogue enhancement feature to help make voices sound more clear and crisp, as well as a TruVolume feature that balances out the volume level across different programs.

Connectivity
Connectivity
Inputs/Outputs - Bar
Optical Audio In
1
HDMI Out
eARC
HDMI 2.1 Class Bandwidth
No
Full HDMI In
1
Analog Audio In 3.5mm (Aux)
1
RCA In
No
USB for Files
1
Ethernet
No
Subwoofer Output
No

The Vizio M51a-H6 has several inputs, including a 3.5mm AUX port that lets you connect older devices to the bar over a wired connection. There's also a Full HDMI In port, so you can use the bar as a hub between your different devices.

9.9
Connectivity
Audio Format Support: ARC/eARC
Dolby Atmos
Supported
Dolby Digital
Supported
Dolby Digital Plus
Supported
Dolby TrueHD
Supported
DTS
Supported
DTS:X
Supported
DTS-HD MA
Supported
PCM Channels
Up To 5.1

Over its HDMI ARC port, this soundbar supports lots of different audio formats. It supports Dolby Digital and DTS, which are two of the most common formats found on streaming platforms and Blu-ray discs. It even supports higher-end formats like Dolby Atmos.

9.9
Connectivity
Audio Format Support: HDMI In
Dolby Atmos
Supported
Dolby Digital
Supported
Dolby Digital Plus
Supported
Dolby TrueHD
Supported
DTS
Supported
DTS:X
Supported
DTS-HD MA
Supported
PCM Channels
Up To 5.1

The Vizio M51a-H6 also has incredible sound format support via Full HDMI In. You can playback surround sound formats commonly found on streaming platforms like Netflix and Hulu like Dolby Digital and DTS.

10
Connectivity
Audio Format Support: Optical
Dolby Digital
Supported
DTS
Supported
PCM Channels
2.0

The Vizio M51a-H6 also supports Dolby Digital and DTS content through its Optical In port. These formats are commonly found on streaming platforms as well as Blu-ray discs.

7.3
Connectivity
Audio Latency: ARC
PCM-2.0 ch
98 ms
PCM-5.1 ch
105 ms
Dolby MAT (PCM) Atmos
103 ms
Dolby Digital
99 ms
Dolby Digital Plus
105 ms
Dolby Digital Plus Atmos
121 ms

The latency over the ARC connection is decent. While Dolby Digital formats have noticeable latency, it's worse with Dolby Digital Plus Atmos. You'll likely notice a lip-sync mismatch between your audio and video, but some apps and TVs can compensate for the latency.

9.0
Connectivity
Audio Latency: HDMI In
PCM-2.0 ch
105 ms
PCM-5.1 ch
82 ms
Dolby MAT (PCM) Atmos
95 ms
Dolby Digital
93 ms
Dolby Digital Plus
82 ms
Dolby Digital Plus Atmos
90 ms

The Vizio M51a-H6 has fantastic HDMI In latency performance. Latency is fairly low with most formats, so it's a solid choice for watching videos and movies. However, some apps and TVs compensate for latency differently, so your real-world experience may vary.

5.6
Connectivity
Audio Latency: Optical
PCM-2.0 ch
240 ms
Dolby Digital
156 ms

The Optical connection's latency is sub-par. Standard two-channel PCM has quite high latency, leading to audio mismatch with video. Dolby Digital's latency is better but still high enough that you will likely want to compensate for the lag in an app or TV settings.

8.7
Connectivity
Video Passthrough To TV
1080p Max Refresh Rate
120Hz
1080p @ 4:4:4 Max Refresh Rate
120Hz
4k Max Refresh Rate
60Hz
4k @ 120Hz @ 10-Bit
Not Supported
4k @ 4:4:4 Max Refresh Rate
60Hz
8k Max Refresh Rate
30Hz
HDR10 Passthrough
Yes
HDR10+ Passthrough
Yes
Dolby Vision Passthrough
Yes
HDMI Forum VRR Passthrough
Yes
FreeSync Passthrough
Yes
G-SYNC Passthrough
No
ALLM Passthrough
Yes

This soundbar can passthrough 4k at 60Hz, but only supports 120Hz passthrough at 1080p resolution. When connected between your PC and your TV, text looks clear and crisp on your TV.

6.0
Connectivity
Wireless Playback
Bluetooth
Yes
Wi-Fi Playback
No
Chromecast built-in
No
Apple AirPlay
No
Spotify Connect
No

You can stream audio wirelessly from your phone or your tablet to the soundbar via Bluetooth.

Additional Features
Additional Features
Interface
Display
No

There is a set of vertical lights on the left side of the bar that flashes depending on the settings you control and adjust. It also displays the volume level. There's audio feedback when you change between the different EQ presets and change the input.

Additional Features
Bar Controls

The Vizio M51a-H6 has several physical buttons on top of the bar. You can power the bar on/off, change the input, activate Bluetooth pairing mode, and adjust the volume.

Additional Features
Remote

The remote is fairly simple and lets you control all of the bar's settings. It also has a display screen.

Additional Features
Voice Assistants Support
Amazon Alexa
No
Google Assistant
No
Apple Siri
No
Microphone Mute
No

The Vizio M Series M51a-H6 doesn't have built-in voice assistant support. That said, the manufacturer says that you can use its AUX In port to connect third-party voice assistant enabled devices.