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Vizio SB3621 VS SB3821

These soundbars may look very similar on the outside, but their specs tell us that they share very little beyond that. When choosing between the two, you wouldn’t want to waste your time researching only to return a product because it’s not a good fit—we’ve done the legwork so you can avoid this very problem.

Vizio SB3621 or SB3821?

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Features of Both Vizio SB3621 and SB3821

Let’s take a closer look at the features of the Vizio SB3821 VS SB3621.


The SB3621 is a winner if you want a more compact-sized soundbar. It has a slimmer design and profile that would suit smaller TVs. It is also ideal for small to medium-sized rooms because it can utilize the acoustics to permeate the space with high-quality audio.

The Vizio SB3821 has a larger footprint, making it less suitable for smaller spaces but perfect for larger TVs. Its size also contributes to it being heavier. Both soundbars are wall mountable, but the SB3821 would need stronger brackets.

Both soundbars also feature a sleek and polished design with silver accents, which is a Vizio classic. The brushed black with brushed silver look makes both devices blend in well with any interior.

On both soundbars, you can find a control panel with a power button, volume controls, input and Bluetooth. Having a control panel gives users the luxury of inputting basic settings in the absence of a remote control.

Power Output on the Vizio SB3621 and SB3821

Interestingly, the Vizio SB3621 actually provides a higher power output of 100 watts compared to the SB3821 which has an output of 60 watts despite the former being the smaller soundbar. This gives the SB3621 a clear advantage over the alternative in terms of powerful sound.

Still, even with a lesser 60 watts, the SB3821 soundbar packs a punch for any content played on screen. With the help of the subwoofers, the difference in wattage when both soundbar subwoofer systems are operating at full capacity is barely noticeable.

Read more about wattage and soundbars here.


Both the Vizio SB3621 and the SB3821 are 2.1 channel soundbars. This means that they both feature left and right channels, and one subwoofer. Even with just two channels, both soundbars are professionally tuned to provide high-quality sound for any content.

We found that the Vizio SB3621 soundbar is capable of matching any highs and lows with minimal distortion, similar to previously reviewed soundbars that come highly recommended. Meanwhile, the quality of the SB3821 that really stands out is the ability to fill large rooms with expansive audio.


Both soundbars come with their own external wireless subwoofers. The wireless setup allows for more flexibility and maximization of the space to find the right placement for the subwoofers

It’s difficult to choose a winner in terms of the subwoofer as the Vizio SB3621 VS 3821 are neck and neck in this department. They both deliver breathtaking audio that takes you by surprise considering the compact size of the subwoofers.

No matter at what volume you enjoy your content, both subwoofers offer minimal distortion and touch every frequency gracefully.

Dont have the space? Consider these popular soundbars without subwoofers.

Sound Technology on the Vizio SB3621 and SB3821

In terms of sound quality and technology, both soundbars offer the same advanced decoding of Dolby Digital and increase the clarity of the audio with DTS Studio Sound, DTS TruSurround, and DTS TruVolume.

With the help of these state-of-the-art technologies for reaching a complete theater experience, both soundbars allow users to be completely immersed in multi-dimensional sound with just two channels.

Sound Settings

A soundbar isn’t complete if it doesn’t provide you autonomy over certain settings. The SB3621 offers both music and movie equalizer settings to help enhance the speech and sound effects when enjoying your content.

The SB3821 soundbar is a little less high-tech as it only offers bass and treble control. This leaves you with a trial and error approach on the soundbar’s settings without the help of preset sound modes. The equalizer sound settings can be accessed via remote control.

Control on the Vizio SB3621 and SB3821

Speaking of the remote control, both soundbars come with their own in the box. However, it’s not the only way to input your desired settings into the soundbar. Other than its built-in control panels, the SB3621 also has a compatible app that can be used to configure the soundbar as desired.

Unfortunately, this feature is absent in the SB3821 soundbar, which can only be controlled with the included remote and embedded control panel.


Bluetooth is a common useful feature we would suggest looking for in a soundbar. Both Vizio soundbars possess wireless Bluetooth connectivity for streaming content right from your mobile devices.

Connections on the Vizio SB3621 and SB3821

For wired connections, the winning spot goes to the Vizio SB3821. It offers more methods of connection than the SB3621 which include stereo RCA, 3.5mm stereo mini jack and a USB port for audio playback.

One drawback both soundbars suffer from is the lack of HDMI inputs [1]. It is the recommended connection since it is able to relay both audio and visual signals.


Setup is a breeze for both Vizio soundbars as the package comes with all the components you need. Inside the box, you will find the necessary cables, wall mount kit, remote control and user manual.

These soundbars both have plug-and-play designs, thanks to connection options that allow users to go from unboxing to enjoying their new soundbar in a matter of minutes.

Overall Winner: Vizio SB3621

Smaller and more affordable isn’t necessarily lesser, as our experts have proven with the Vizio SB3621.

Even with its compact size that’s best suited for smaller spaces, it, together with its external subwoofer, can fill the room with great quality sound regardless of the content. For movie lovers, it comes with a plus: the Vizio SB3621 is similar to more expensive options in that it has DTS and Dolby decoding abilities.

Distortion is not a problem for this budget option as well. Bluetooth not only provides this pick with the chance to play content from your mobile devices, but it also affords flexibility in soundbar and subwoofer placement.

Need more from your Vizio soundbar? This one has six full-range speakers for a more immersive viewing experience.

Willie Greer

Willie Greer is the founder of The Product Analyst. A cinephile, he has made it a personal quest to achieve the awesomest home theater possible. He now shares what he has learned through the years on the site, and has enlisted the help of tech-savvy colleagues in providing more insight about today’s most sought-after gadgets.
Willie Greer

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