Reviews

Polk Audio Signa S4 Soundbar: Review

The $399 Polk Audio Signa S4 Soundbar offers Dolby Atmos and a subwoofer. How does it measure up?

Updated

February 26, 2022

Late in 2021, Polk Audio released its first soundbar to include Dolby Atmos, the Signa S4. For all the feature and specification details, refer to our initial report.

Since that report, Polk Audio sent us a review sample to check out and this article discusses our actual hands-on experience with the Signa S4.

Polk Audio Signa S4 Feature Recap

The Polk Audio Signa S4 has a 3.1.2 channel configuration grouped with five horizontal facing speakers (the left and right channels have a tweeter and midrange) and two vertically firing full-range speakers. The .1 refers to the subwoofer channel.

The Signa S4’s two vertically firing speakers are used to support Dolby Atmos height channels as well as the S4’s built-in up-mixer that provides an immersive height-channel effect from non-Dolby Atmos content.

The Signa S4 includes a VoiceAdjust™ feature to improve the sound presence of voice and dialog. Voice Adjust is paired with the S4’s center channel speaker.

In addition to the soundbar, a ported downward firing wireless subwoofer with a 6-inch driver is included. The Signa S4 includes a Bass Adjust control for the subwoofer on the remote.

The Signa S4 also provides Sound Mode/EQ presets for Movie, Music, and Night Listening (Night Mode).

The Signa S4 comes with a wireless remote control and also has onboard control buttons for power, input selection, Bluetooth pairing, and volume.

Connections

Here are the connection options available on the Signa S4

(1) HDMI (ARC/eARC) input.
(1) Digital optical input
(1) Analog 3.5mm input (Aux)
(1) USB-A (for firmware updates and service only)

Tip: Bluetooth is also included for streaming music from compatible devices, such as smartphones.

What The Signa S4 Package Includes

In addition to the soundbar and subwoofer, here is what else is included in the Signa S4 package:

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Quick Start Guide and other documents
Remote control (batteries included)
Soundar and Subwoofer Power Cables
HDMI cable
Digital Optical cable
Wall-mount template
Wall-mount spacers

Hands-On With the Polk Audio Signa S4 Soundbar

Now that you are familiar with the features of the Signa S4 and what it comes with, here is how to get it up and running and what to expect in terms of performance.

Set-Up

Step 1: Place the soundbar and subwoofer where you want them but prepare to move the subwoofer to find the best bass response after you hear the initial results. The 41-inch width of the soundbar complements TVs of various screen sizes well in both appearance and soundstage width. With its thin profile, the S4 easily fits below TV screens.

Tip: If you are wall mounting the soundbar, Polk Audio provides a wall-mounting template and wall mount spacers. Additional wall mounting hardware is not provided. I did not use the wall mounting option.

Step 2: Connect the provided HDMI cable from the soundbar to the HDMI-ARC/eARC port on your TV.

(Optional) Connect the provided digital optical cable from the TV to the soundbar.

(Optional) Connect an analog audio cable (RCA to 3.5mm or 3.5mm to 3.5mm – not provided) from the TV to the soundbar.

Step 3: Plug the soundbar and subwoofer to power using the provided power cords.

Step 4: Turn the soundbar and subwoofer on and they should pair.

Step 5: Put batteries in the remote and start using your system.

Connecting HDMI-ARC/eARC

HDMI ARC and eARC transfer audio from your TV (including the audio from devices connected to your TV) to the soundbar. ARC typically passes stereo and Dolby Digital audio; eARC additionally passes Dolby Atmos.

If your TV doesn’t have eARC you can also use HDMI ARC, digital optical, or 3.5 mm analog audio connections from your TV to the soundbar, but you will not be able to access Dolby Atmos.

HDMI ARC/eARC can sometimes be a little tricky to get working, but in my case, the TV and soundbar “locked in” through the connection easily.

Using The Signa S4: Dolby Atmos and More

When connected to an HDMI eARC equipped TV, Dolby Atmos height effects from compatible content were provided, via the S4’s vertically firing speakers. You won’t get the same experience as you would with Dolby Atmos surround systems that include ceiling-mounted speakers, but that is to be expected within a soundbar platform. However, as executed on the Signa S4, Dolby Atmos definitely broadens the front soundstage and provides overhead sound perception that goes beyond the physical dimensions of the soundbar.

The Signa S4 has a master volume control and separate bass level control for the subwoofer, but it would have been nice to also include an additional height channel control so that those channels could be more adaptable to ceiling height and perhaps improve the intended immersive effect where needed.

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One connection limitation is that the S4 doesn’t have an extra HDMI input to accommodate an external device, such as a Blu-ray/UHD Blu-ray Disc player or media streamer if it can’t be connected, or shouldn’t be connected to the TV.

The reason that it would have been good to include an extra HDMI input is that although you can access native Dolby Atmos from TVs with an HDMI eARC connection – most TVs only have HDMI ARC which can only pass Dolby Atmos if it is encoded within a Dolby Digital Plus signal – However, not all TVs with HDMI ARC are Dolby Digital Plus compatible.

Tip: An extra HDMI input would not only provide more flexible access to Dolby Atmos but also provide video pass-through to the TV from devices connected to the soundbar, which is handy if your TV doesn’t have enough HDMI inputs.

If Dolby Atmos content is not accessible via your TV/soundbar setup, the S4 does have an upmixing function that provides a Dolby Atmos-like listening experience for non-Dolby Atmos content. Although the upmixing effect is more subtle than true Dolby Atmos, it brings added dimension to movies when true Dolby Atmos isn’t available.

The compact subwoofer provides a good bass complement to the Signa S4. Using both disc-based and online frequency tests, I found that I could hear an audible low-frequency response down to 40Hz, dropping off abruptly below that point. The low-frequency response is satisfactory for this modest system.

Final Thoughts

Despite some connectivity shortcomings, the Signa S4 definitely delivers a good soundbar listening experience for both movies and music. In addition to Dolby Atmos, the inclusion of Voice Adjust also makes the S4 a good option for those that have trouble hearing voices on TV shows and movies, as well as providing better voice clarity on content that just isn’t mixed well.

The big add-on feature in soundbars these days is Dolby Atmos and the way it is executed varies between brands. The Polk Audio Signa S4 does a good job of both providing Dolby Atmos and height-channel upmixing at a reasonable price.

Time to spice up your TV viewing experience!