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Vizio M Series M21d-H8R Soundbar Review

Tested using Methodology v1.0
Reviewed Feb 23, 2021 at 07:43 am
Latest change: Writing modified Sep 27, 2022 at 01:18 pm
Vizio M Series M21d-H8R Picture

The Vizio M-Series M21d-H8R is a 2.1 soundbar with two subwoofers integrated into the bar. Its neutral, though slightly boomy sound profile makes it suitable for listening to lots of different types of audio content, and it even has a few EQ presets to help you customize its sound. Unfortunately, it can't really reproduce low-bass, so you don't feel the deep thumps and rumbles in action-packed movies or bass-heavy music. Also, while it gets loud, there's a lot of compression when you play it at max volume, which is disappointing if you like to crank up the volume at parties.

Our Verdict

N/A Mixed Usage

The Vizio M Series 2.1 Soundbar is alright for mixed usage. It has a pretty neutral, though slightly boomy sound profile that makes it suitable for listening to a wide range of audio content. Unfortunately, it lacks low-bass, so you don't really feel the deep rumbles in action-packed movie scenes. It also has to downmix surround content into stereo, and it doesn't support Dolby Atmos content. However, there are a few sound enhancement features available, which is nice.

Pros
  • EQ presets.
  • Dialogue enhancement feature.
Cons
  • Downmixes surround content into stereo.
  • Lacks low-bass.
N/A Dialogue/TV Shows

The Vizio M Series 2.1 Soundbar is good for dialogue and TV shows. Even though it lacks a dedicated center channel, its balanced mid-range can still reproduce vocals clearly and accurately. It even has a dialogue enhancement feature that can make dialogue sound more clear and crisp. Since it's Bluetooth-compatible, you can also wirelessly stream podcasts and audiobooks from your phone to the bar. While it gets pretty loud, unfortunately, there's a lot of compression when you play it at max volume.

Pros
  • Gets loud.
  • Dialogue enhancement feature.
  • Bluetooth-compatible.
Cons
  • A lot of compression at max volume.
N/A Music

The Vizio Vizio M Series 2.1 Soundbar is decent for music. It has a pretty neutral, though slightly boomy sound profile suitable for most music genres. However, it struggles to reproduce thumpy low-bass, which can be disappointing if you like to feel the deep rumble in bass-heavy music like EDM. There are a few EQ presets as well as bass and treble adjustment features to help you customize its sound, but it lacks a full graphic EQ. Also, while it gets loud, there's a lot of compression at max volume.

Pros
  • Gets loud.
  • EQ presets.
Cons
  • A lot of compression at max volume.
  • Lacks low-bass.
N/A Movies

The Vizio M Series 2.1 Soundbar is mediocre for movies. Its balanced mid-range can reproduce clear and accurate dialogue, but it struggles to reproduce a thumpy low-bass for action-packed scenes. It gets loud, but there's a lot of compression when you play it at max volume. Also, it can play surround content, but it has to downmix it into stereo to play it. It also doesn't support Dolby Atmos content.

Pros
  • Gets loud.
  • EQ presets.
Cons
  • A lot of compression at max volume.
  • Downmixes surround content into stereo.
  • Lacks low-bass.
  • N/A Mixed Usage
  • N/A Dialogue/TV Shows
  • N/A Music
  • N/A Movies
  1. Updated Sep 27, 2022: Added market comparison for the Vizio M Series M213ad-K8 to the 'Height (Atmos)' box.
  2. Updated Sep 19, 2022: Identified an error in our original compression testing and updated the 'Stereo Dynamics' and 'Stereo THD' tests respectively. Updated the bar's wall-mount holes to 'Proprietary'. Added additional information to 'Voice Assistant' and 'Other Input Specifications' boxes.
  3. Updated Feb 23, 2021: Review published.
  4. Updated Feb 18, 2021: Early access published.

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Differences Between Sizes And Variants

The Vizio M21d-H8R comes in Black, and you can see the label for the model we tested here. You can also purchase another variant called the Vizio M21d-H8, which comes with a remote control but it lacks backlighting and a display screen.

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

Compared To Other Soundbars

The Vizio M Series 2.1 soundbar comes with two subwoofers integrated into the bar. It's an upgrade over the Vizio SB362An-F6, and it comes with a Full HDMI In port that supports 4k passthrough. It has a pretty neutral, though slightly boomy sound profile out-of-the-box, but it struggles to reproduce a thumpy low-bass. While it gets loud, there's a lot of compression present at max volume, so it may not be ideal to use at a crowded party.

See also our recommendations for the best soundbars under $200, the best Vizio soundbars, and the best soundbars for dialogue.

Vizio V Series V21x-J8

The Vizio V Series V21x-J8 is better than the Vizio M-Series M21d-H8R. The V Series comes with a dedicated sub that can reproduce a more extended low-bass. It also has a better soundstage performance, and far less compression when you play it at max volume. That said, the standalone M-Series is better suited if you don't have a lot of space in your room.

Vizio M Series M213ad-K8

The Vizio M Series M213ad-K8 is better than the Vizio M Series M21d-H8R. They're both 2.1 budget bars with a similar standalone design, but the M213ad-K8 adds support for Dolby Atmos. Of course, it has to downmix it into stereo to play it, which isn't very immersive-sounding. Still, it adds eARC support, and it has lower latency.

Vizio V Series V21-H8

The Vizio V Series V21-H8 is a better soundbar than the Vizio M-Series M21d-H8R. The V Series has a more neutral sound profile and a better soundstage performance. Also, it gets louder with much less compression at max volume. However, the M-Series is better-built, and it has a Full HDMI In port that supports 4k passthrough.

Sonos Arc

The Sonos Arc is better than the Vizio M-Series M21d-H8R. The Sonos is a better-built 5.0.2 setup with better soundstage, center, and surround performances. Unlike the Vizio, it supports Dolby Atmos content and built-in voice assistant capabilities. It also gets louder with less compression at max volume. However, only the 2.1 Vizio comes with a Full HDMI In port and EQ presets.

Vizio V Series V51-H6

The Vizio V Series V51-H6 is a better soundbar than the Vizio M-Series M21d-H8R. The V Series is a 5.1 setup that comes with a dedicated subwoofer and two surround speakers, and it has better center and surround channel performances. It also has a more neutral sound profile, and it gets louder with less compression at max volume. That said, the 2.1 M-Series is better-built, and it comes with a Full HDMI In port that supports 4k passthrough.

Vizio M Series M51a-H6

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 it supports Atmos content. It also gets louder with much less compression at max volume. However, the 2.1 M21d-H8R is better built.

Sony HT-X8500

The Sony HT-X8500 and the Vizio M-Series M21d-H8R are very similarly performing 2.1 soundbars, so depending on your listening habits, you may prefer one over the other. The Vizio is better built, and it has a more neutral sound profile out-of-the-box. However, the Sony has a lot less compression when you play it at max volume, and it can also support Dolby Atmos content, though it has to downmix it to play it.

Vizio M Series M51ax-J6

The Vizio M Series M51ax-J6 and the Vizio M-Series M21d-H8R are two very different soundbar setups. The M21d-H8R is a 2.1 standalone soundbar that's ideal for listening to vocal-centric content like TV shows. That said, the M51ax-J6 is better overall. It's a 5.1 bar with Dolby Atmos support that can reproduce a more extended low-bass thanks to its dedicated sub. Its satellites offer a better surround performance, too, and it has a better soundstage.

TCL Alto 8i

The TCL Alto 8i is a bit better than the Vizio M-Series M21d-H8R. The TCL has a lot less compression when you play it at max volume, and it also supports Dolby Atmos content. However, the Vizio is better built.

Sonos Beam

The Sonos Beam is a better soundbar than the Vizio M-Series M21d-H8R. The Sonos is better built, and it has a more balanced sound profile. It also has a better soundstage performance, and it gets louder with less compression when you play it at max volume. However, the Vizio comes with some EQ presets, unlike the Sonos, and it has a Full HDMI In port that supports 4k passthrough.

Vizio SB36512-F6

The Vizio SB36512-F6 is a better soundbar than the Vizio M-Series M21d-H8R. The 5.1.2 SB36512-F6 has a more neutral sound profile and a better soundstage performance. Also, thanks to its dedicated center channel and dedicated surround speakers, it offers better center and surround channel performances. It supports Atmos, too. However, the 2.1 M-Series comes with a dialogue enhancement feature, which is handy.

Vizio M Series M512a-H6

The Vizio M Series M512a-H6 is better than the Vizio M-Series M21d-H8R. The M512a-H6 is a 5.1.2 setup with a dedicated sub and satellites. It can reproduce a more extended low-bass and has better surround and soundstage performances. It even has Dolby Atmos support, unlike the standalone M21d-H8R.

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Test Results

perceptual testing image
Design
Design
Style - Bar

The Vizio M21d-H8R is a sleek soundbar with a unique, trapezoidal shape. It's mostly covered by a tight cloth material, and the sides and the bottom are made of plastic. The buttons are located on the right side of the bar.

Design
Style - Subwoofer

This setup doesn't come with a subwoofer. Instead, it has subwoofers integrated into the bar.

Design
Style - Satellites

This setup doesn't come with any satellite speakers.

Design
Dimensions - Bar
Width Lock" (Lock cm)
Height Lock" (Lock cm)
Depth Lock" (Lock cm)

The Vizio M21d-H8R is a bit long, and it may not 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 N/A
Height N/A
Depth N/A
Design
Dimensions - Satellites
Width N/A
Height N/A
Depth N/A
Design
Back - Bar
Bar Mounting
Locked

On the back of the bar, there's an opening for the power cable and the inputs. You can also wall-mount the bar using the included brackets.

Design
Back - Subwoofer
Enclosure
Locked
Design
Back - Satellites
Mounting
Locked
N/A
Design
Build Quality

The Vizio M21d-H8R has a good build quality. The sides and the bottom are made of plastic, which feels solid. The tight fabric material covering the bar doesn't seem like it could rip easily, though it may collect some dust over time.

Design
In The Box
HDMI Cable Length
Lock m (Lock ft)
Digital Optical Cable Length
Lock m (Lock ft)

  • Manuals
  • Optical cable
  • HDMI cable
  • 3.5mm to 3.5mm audio cable
  • Stereo RCA to 3.5mm cable
  • Remote with batteries (2xAAA)
  • 2x Wall-hang parts
  • Power cable
  • Mounting template

Sound
N/A
Sound
Stereo Frequency Response
Tested Preset
Locked
Slope
Lock
Std. Err.
Lock dB
Channels
2.1
Low-Frequency Extension
Lock Hz
High-Frequency Extension
Lock kHz

When set to its 'Music' preset, the Vizio M21d-H8R has a decent stereo frequency response. It has a pretty neutral sound profile suitable for listening to lots of different audio genres, and the extra boom in the bass range can please fans of bass-heavy music like EDM. However, it struggles to reproduce a thumpy low-bass, so you don't really feel the rumble in action-packed movie scenes. There are some EQ presets, as well as bass and treble adjustment features to help you customize its sound more to your liking.

N/A
Sound
Stereo Frequency Response With Preliminary Calibration
Suggested Preset
Locked
Suggested Bass Setting
Lock
Suggested Treble Setting
Lock
Slope
Lock
Std. Err.
Lock dB
Low-Frequency Extension
Lock Hz
High-Frequency Extension
Lock kHz

With calibration, the Vizio M21d-H8R has a decent stereo frequency response. It still has a pretty neutral, though slightly boomy sound profile that adds a little extra warmth to your mixes. However, because it lacks a dedicated subwoofer, it still struggles to reproduce the deep thumps and rumbles from the low-bass.

N/A
Sound
Stereo Soundstage
Crosstalk Error
Lock dB

This soundbar has a fair stereo soundstage performance. While the soundstage is barely as wide as the bar itself, it has decent focus, so objects like voices and instruments generally seem to come from an accurate location instead of a general area.

N/A
Sound
Stereo Dynamics
SPL @ Max Volume
Lock dB SPL
DRC @ Max Volume
Lock dB

The Vizio M21d-H8R has fair stereo dynamics. It gets loud, so it can easily fill up a larger living space with sound. That said, there's a bit of compression present when you crank it up to max volume, so your audio doesn't sound as clear or clean as it does at quieter volumes.

N/A
Sound
Stereo Total Harmonic Distortion
Weighted THD @ 80dB
Lock
Weighted THD @ Max Volume
Lock

This soundbar has an impressive THD performance. At normal listening volumes, distortion falls within good limits, meaning that audio remains clear and crisp. While there's a slight jump in distortion at max volume, this shouldn't be an issue for more casual listenersโ€”distortion is ultimately quite difficult to hear with real-world content.

N/A
Sound
Center
Localization
Locked
Slope
Lock
Std. Err.
Lock dB
SPL @ Max Volume
Lock dB SPL
Weighted THD @ 80dB
Lock
Weighted THD @ Max Volume
Lock

The Vizio M21d-H8R has an adequate central channel performance. This 2.1 setup uses its left and right speakers to simulate a sound in the center, which sounds more diffused and less clear than a dedicated center speaker. That said, it still reproduces a balanced mid-range, so dialogue in TV shows is still fairly clear and accurate.

N/A
Sound
Surround 5.1
Localization
Locked
Slope
Lock
Std. Err.
Lock dB
SPL @ Max Volume
Lock dB SPL
Weighted THD @ 80dB
Lock
Weighted THD @ Max Volume
Lock
7.1 Rears
Locked

This soundbar has poor surrounds performance. It's a 2.1 setup, so it has to downmix surround content into stereo to play it. However, this doesn't produce the most accurate or clear representation of surround objects, and sound seems like it's coming from in front of you rather than from speakers placed all around you.

N/A
Sound
Height (Atmos)
Localization
Locked
Slope
N/A
Std. Err.
N/A
SPL @ Max Volume
N/A
Weighted THD @ 80dB
N/A
Weighted THD @ Max Volume
N/A

If you want a bar with a similar design that adds Atmos support, check out the Vizio M Series M213ad-K8.

N/A
Sound
Sound Enhancement Features
Room Correction
Locked
Dialogue Enhancement
Locked
Auto-Volume/Night Mode
Locked
Subwoofer Level Adjustment
Locked
Bass Adjustment
Locked
Treble Adjustment
Locked
EQ
Locked
Surround Level Adjustment
Locked
Rear Level Adjustment
Locked
Height Level Adjustment
Locked
Virtual Surround
Locked

The Vizio M21d-H8R has a poor selection of sound enhancement features. It comes with four EQ presets: 'Movie', 'Music', 'Dialogue', and 'Game'. There's also a TruVolume feature that provides a consistent volume level across different programs, such as commercials and TV shows. However, it lacks a full graphic EQ, and it doesn't have a room correction feature, so it may sound a bit different depending on the room you use it in.

Connectivity
Connectivity
Physical Inputs - Bar
Optical Audio In
Locked
HDMI ARC
Locked
HDMI Out
Locked
Full HDMI In
Locked
Analog Audio In 3.5mm (Aux)
Locked
RCA In
Locked
USB for Files
Locked
Ethernet
Locked

The Vizio M21d-H8R has several inputs. There's a 3.5mm AUX port, which lets you wire older devices to the bar to listen to audio. There's also a Full HDMI In port, which lets you use the bar as a hub between different devices.

N/A
Connectivity
Audio Format Support - ARC
eARC
Locked
Dolby Atmos
Locked
Dolby Digital
Locked
Dolby Digital Plus
Locked
DTS
Locked
DTS:X (eARC only)
Locked
Dolby TrueHD (eARC only)
Locked
DTS-HD MA (eARC only)
Locked
5.1 PCM (eARC only)
Locked

The Vizio M Series 2.1 soundbar supports some of the most common formats for streaming platforms and Blu-ray discs, including Dolby Digital and DTS. However, it doesn't support higher-end formats like Dolby Atmos.

N/A
Connectivity
Audio Format Support - Full HDMI In
Dolby Atmos
Locked
DTS:X
Locked
Dolby Digital
Locked
Dolby Digital Plus
Locked
DTS
Locked
Dolby TrueHD
Locked
DTS-HD MA
Locked
5.1 PCM
Locked

This soundbar supports Dolby Digital content over its Full HDMI In port, but it lacks support for other higher-end formats like Dolby Atmos.

N/A
Connectivity
Audio Format Support - Optical
Dolby Digital
Locked
DTS
Locked

The Vizio M21d-H8R supports both Dolby Digital and DTS content via its Optical Audio In. These formats are typically found on Blu-ray discs and streaming platforms.

N/A
Connectivity
Latency
- SAMPLE -
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Vizio M Series M21d-H8R Latency Video Sample
ARC
Lock ms
Optical
Lock ms
Full HDMI In
Lock ms

The Vizio M Series 2.1 soundbar has a disappointing latency performance. Its latency via Full HDMI In is low enough to be suitable for watching videos, but there's a significant delay between the picture and the audio via ARC and Optical In. However, some apps and some TVs compensate for latency differently, so your real-world experience may vary.

N/A
Connectivity
Wireless Playback
Bluetooth
Locked
Wi-Fi
Locked
Chromecast built-in
Locked
Apple AirPlay
Locked

The Vizio M21d-H8R only supports Bluetooth connectivity, so you can stream audio from your phone to the bar wirelessly. However, you can't connect your devices to the bar using Wi-Fi, Chromecast, or Apple AirPlay.

Connectivity
Other Input Specifications
4k @ 60 Hz Passthrough
Locked
4k @ 60 Hz @ 10 bit Passthrough
Locked
4k @ 60 Hz @ 4:4:4 Passthrough
Locked
HDR10 Passthrough
Locked

The Vizio M21d-H8R can passthrough some of the highest bandwidth signals. For example, it supports Dolby Vision Passthrough. However, it can't passthrough 4k @ 120Hz.

Connectivity
Connectivity - Subwoofer
Sub Wireless
Locked
Connectivity
Connectivity - Satellites
Sat Wireless
Locked
Additional Features
Additional Features
Interface
Display
Locked

In the middle of the bar, there are lights that flash depending on your settings. There's also audio feedback when you select one of the four EQ presets and when you change the input.

Additional Features
Bar Controls

On the right side of the bar, there are buttons that let you power the bar on/off, change the input, activate Bluetooth pairing, and adjust the volume.

Additional Features
Remote
Universal Remote
Locked

The remote is quite simple, and it lets you control all of the bar's settings. Like the Vizio V Series V51-H6, it also has a display screen.

Additional Features
Voice Assistants Support
Amazon Alexa
Locked
Google Assistant
Locked
Apple Siri
Locked

While the bar doesn't have an integrated voice assistant, you can still control it with your voice if you pair it to a third-party device. For example, you can connect an Amazon Echo or a Google Home using the bar's AUX VA port.

Additional Features
App
App Name Locked
iOS Locked
Android Locked
Acts As A Remote
Locked
Controls Soundbar's Settings
Locked
Casts Device Files
Locked
Additional Features
Other Features
Power Saving
Locked
HDMI CEC (TV Remote Control)
Locked

This soundbar has an eco-power mode that powers down the bar after a period of inactivity. It also supports HDMI CEC, so you can use your TV remote to control the bar's basic functions.