Vizio M21d-H8 vs Polk Audio Signa S3 review

Votes 1 1
Rating 5 5

Vizio M21d-H8 vs Polk Audio Signa S3 comparison chart

Vizio M21d-H8
Polk Audio Signa S3

Vizio M21d-H8 vs Polk Audio Signa S3 review

Vizio M21d-H8
Polk Audio Signa S3

The Vizio M21d-H8 vs Polk Audio Signa S3 comparison shows that these models have some important differences and common features. The Vizio M21d-H8 was rated 5, while the Polk Audio Signa S3 has a rating 6.4. The soundbars are equipped with a different number of buttons, power, volume down, volume up, source, Bluetooth for the M21d-H8 and power, source, demo, volume down, volume up for the Signa S3.

Audio features

Each of the models under consideration has active amplification type. By the number of channels, the devices do not differ. A built-in subwoofer is available only in the Vizio M21d-H8. Rate 5 out of 10 received the Vizio M21d-H8 for audio features and specs, but the Polk Audio Signa S3 received 4 out of 10.

Streaming services

The Signa S3 can play audio from Spotify.


Wireless Internet connection is realized only in the Signa S3. Soundbars from this comparison have Bluetooth support. There are 1/1 HDMI inputs/outputs in the Vizio M21d-H8 versus 1/0 HDMIs in the Polk Audio Signa S3. As in the M21d-H8, so in the Signa S3 there is the HDMI Audio Return Channel (ARC). Connecting devices via USB is possible in both models. We rated the connectivity of the M21d-H8 at 6 out of 10, while the Signa S3 was rated 5/10. The manufacturer of the Signa S3 provides a device control application. The soundbars in this review are equipped with a microphone. The models under consideration cannot become part of a multiroom system.

Multichannel surround

Dolby Atmos audio decoder support is not implemented in either the M21d-H8 or Signa S3. Devices from this comparison cannot process surround sound due to lack of DTS:X. The M21d-H8 was rated 5/10, while the Signa S3 received a mark of 4/10 for multichannel surround.

Advantages Vizio M21d-H8 over Polk Audio Signa S3

  • Built-in subwoofer

Advantages Polk Audio Signa S3 over Vizio M21d-H8

  • Separate subwoofer in package
  • Amazon Music compatible
  • Spotify support
  • WI-FI enabled
  • App control
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Vizio M21d-H8
Polk Audio Signa S3


Signa S3


Polk Audio