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Polk Audio Signa S4 Soundbar Review

Tested using Methodology v1.0
Reviewed Mar 25, 2022 at 10:00 am
Polk Audio Signa S4 Picture
6.9
Mixed Usage
7.4
Dialogue/TV Shows
6.9
Music
6.6
Movies
Channels
3.1.2

The Polk Audio Signa S4 is a 3.1.2 setup released in 2021. It's the higher-end bar in Polk's Signa Series, and unlike the Polk Audio SIGNA S2, it supports Dolby Atmos content. Its slightly V-shaped sound adds extra punch in the bass and brightness in the treble to your favorite music. Dialogue still reproduces very clearly, and there's even an adjustable dialogue enhancement feature that lets you control how loud voices sound in the mix. However, it lacks a thumpy low-bass, so you don't feel the excitement in action movies and bass-heavy music.

Our Verdict

6.9 Mixed Usage

The Polk Audio Signa S4 is fair for mixed usage. Its slightly V-shaped sound adds extra punch in the bass and brightness in the treble to your favorite music. Dialogue reproduces quite clearly and accurately, too, and its adjustable dialogue enhancement feature is handy for listening to TV shows and podcasts. Also, it supports Dolby Atmos content. However, the lack of low-bass takes away from the immersive feeling in action movies, and its surround sound performance isn't the most impressive.

Pros
  • Bass adjustment feature.
  • Adjustable dialogue enhancement feature.
Cons
  • Lacks low-bass.
  • Downmixes surround sound into stereo.
7.4 Dialogue/TV Shows

The Polk Audio Signa S4 is satisfactory for dialogue-centric content like TV shows and documentaries. It's a 3.1.2 setup with a discrete center channel that helps anchor voices to a pinpoint location in the soundstage. You can even make voices more clear and crisp using its adjustable dialogue enhancement feature - which Polk calls VoiceAdjust. The Night Mode tool is handy, too, since it reduces the bass and increases the volume of the voices to help you hear dialogue clearly at night.

Pros
  • Adjustable dialogue enhancement feature.
Cons
  • No Wi-Fi, Chromecast, or AirPlay support.
6.9 Music

The Polk Audio Signa S4 is fair for music. Out-of-the-box, it has a slightly V-shaped sound profile that adds a little extra punch in the bass and some brightness in the treble range. Vocals and lead instruments are clearly and accurately reproduced, and higher-pitched instruments sparkle with brightness. You can customize its sound a bit with its bass adjustment feature. However, it can't reproduce the deep thump and rumble in the low-bass found in bass-heavy genres like hip-hop and EDM.

Pros
  • Bass adjustment feature.
  • Bluetooth-compatible.
Cons
  • Lacks low-bass.
  • No treble adjustment.
6.6 Movies

The Polk Audio Signa S4 is okay for movies. It supports Dolby Atmos content with two up-firing drivers built into the bar itself. The performance is pretty good given its price point, but you notice the lack of low-bass in action-heavy scenes. It can also playback surround sound content like Dolby Digital, but the performance isn't the best. Without dedicated surround channels, it has to downmix this content into stereo to play it.

Pros
  • Bass adjustment feature.
  • Adjustable dialogue enhancement feature.
Cons
  • Lacks low-bass.
  • Downmixes surround sound into stereo.
  • 6.9 Mixed Usage
  • 7.4 Dialogue/TV Shows
  • 6.9 Music
  • 6.6 Movies
  1. Updated Mar 25, 2022: Review published.
  2. Updated Mar 18, 2022: Early access published.

Test Results

perceptual testing image
Design
Design
Style - Bar

The Polk Audio Signa S4 has a pretty similar design to the Polk Audio SIGNA S2. Both bars are mostly plastic, with fabric covering the front of the bar. On the S4, fabric covers the entire top of the bar, too.

Design
Style - Subwoofer

The sub looks a bit different than the one that comes with the Polk Audio SIGNA S2. It's mostly melamine, and unlike the S2, there's no fabric on the sub. It also sits on four pegs, and the port is underneath.

Design
Style - Satellites
Design
Dimensions - Bar
Width 41.1" (104.5 cm)
Height 2.4" (6.0 cm)
Depth 3.7" (9.5 cm)

The Polk S4 is quite long, so it doesn't fit between the legs of a 55" TV stand. That said, it's not very tall, so it doesn't obscure your TV screen.

Design
Dimensions - Subwoofer
Width 7.9" (20.0 cm)
Height 12.9" (32.7 cm)
Depth 11.0" (28.0 cm)

The subwoofer is roughly the same size as a desktop computer. It connects to the soundbar wirelessly, handy for placing it wherever you want in your room.

Design
Dimensions - Satellites
Width N/A
Height N/A
Depth N/A
Design
Back - Bar
Bar Mounting
Universal (holes on back)

The back of the bar has some openings for the inputs and the power cables. You'll also find the universal wall mount holes there, which let you mount the bar on your wall.

Design
Back - Subwoofer
Enclosure
Ported

The back of the sub is very plain. There's a pairing button and an input for the power cable.

Design
Back - Satellites
Mounting
No
7.0
Design
Build Quality

The Polk Audio Signa S4 has a satisfactory build quality. The bar itself is mostly plastic, which doesn't feel very premium. However, the fabric on the front and the top of the bar is tight and thick, so it doesn't seem like it rips easily. The subwoofer's melamine build feels more solid than the Polk Audio SIGNA S2, too.

Design
In The Box
HDMI Cable Length
1.5 m (4.9 ft)
Digital Optical Cable Length
1.8 m (5.9 ft)

  • User Guides
  • Remote with 2x AAA batteries
  • 2x wall-mount spacers
  • 2x power cables
  • Optical cable
  • HDMI cable

Sound
7.3
Sound
Stereo Frequency Response
Tested Preset
Music
Slope
-0.83
Std. Err.
3.32 dB
Low-Frequency Extension
47.6 Hz
High-Frequency Extension
16.7 kHz

The Polk Audio Signa S4 has a satisfactory stereo frequency response. Its sound profile is V-shaped, meaning that there's a touch of extra boom in the bass and some extra brightness in the treble that makes vocals and lead instruments sparkle. Dialogue in movies and TV shows is clear and accurate, thanks to the balanced mids. If you like to listen to bass-heavy genres, you'll notice the lack of low-bass since you don't feel the deep thump and rumble on these tracks.

7.3
Sound
Stereo Frequency Response With Preliminary Calibration
Suggested Preset
Music
Suggested Bass Setting
-3
Suggested Treble Setting
N/A
Slope
-0.15
Std. Err.
2.69 dB
Low-Frequency Extension
49.7 Hz
High-Frequency Extension
17.0 kHz

The Polk Audio Signa S4 has a bass adjustment feature to help you customize its sound. When you set it to '-3', the sound profile is more neutral and balanced. Vocals and lead instruments are clear and detailed in the mix. There's still a little extra punch in the mid-to-high bass range; it's less noticeable than with its default sound. That said, bass adjustment features can't make up for the lack of low-bass, so you're still missing the deep rumble in bass-heavy music genres.

7.0
Sound
Stereo Soundstage
Crosstalk Error
1.83 dB

The Polk Audio Signa S4 has a decent soundstage. It's perceived to be about as wide as the bar itself, but it doesn't have any tricks to make it seem wider than that. On the upside, it gives a good sense of height, even with music, so the soundstage seems to reach up over your TV screen. The focus is good, too. For example, if you're listening to an orchestra, each instrument seems to come from an accurate, pinpoint location in the soundstage.

7.1
Sound
Stereo Dynamics
SPL @ Max Volume
87.1 dB SPL
DRC @ Max Volume
1.43 dB

The Polk Audio Signa S4 has decent stereo dynamics. It can get loud enough to fill up an average-sized living room with sound. If you have a larger space, or if you want to crank up the volume for parties, it doesn't get loud enough for these uses.

6.7
Sound
Stereo Total Harmonic Distortion
Weighted THD @ 80dB
1.05
Weighted THD @ Max Volume
2.69

The Polk Audio Signa S4 has an okay stereo THD performance. A normal listening volume of 80 dB is considered loud enough to fill up an average-sized living room with sound. When you listen to audio at this volume, there's a bit of distortion, especially in the bass range. Distortion increases when you push the bar to its max volume. That said, distortion is hard to hear with real-life content, especially at normal listening volumes. However, if you crank up the volume with bass-heavy music, you'll notice that audio reproduction isn't as clean or as pure.

7.5
Sound
Center
Localization
Discrete
Slope
-0.92
Std. Err.
4.35 dB
SPL @ Max Volume
84.0 dB SPL
Weighted THD @ 80dB
0.97
Weighted THD @ Max Volume
2.25

The Polk Audio Signa S4 has a good center channel performance. It's a 3.1.2 setup, meaning that it comes with a discrete center channel. This helps anchor voices to a pinpoint location in the soundstage, so dialogue is clearly and accurately reproduced.

3.4
Sound
Surround 5.1
Localization
Stereo (Downmix)
Slope
-1.69
Std. Err.
4.58 dB
SPL @ Max Volume
86.2 dB SPL
Weighted THD @ 80dB
0.95
Weighted THD @ Max Volume
2.59
7.1 Rears
No

The Polk Audio Signa S4's surround performance is poor, but that's normal for 3.1 soundbars. The bar doesn't come with dedicated surround speakers. Instead, it has to downmix surround sound into stereo to play it. Unfortunately, this doesn't sound as immersive. Audio seems like it's coming from speakers placed in front of you rather than from speakers placed all around you.

5.8
Sound
Height (Atmos)
Localization
Phantom (Up Firing, Bar)
Slope
-1.33
Std. Err.
4.72 dB
SPL @ Max Volume
83.6 dB SPL
Weighted THD @ 80dB
0.70
Weighted THD @ Max Volume
0.95

The Polk Audio Signa S4 has a middling Atmos performance. There are two up-firing drivers built into the bar itself, which ricochet sound off the ceiling to create the illusion of height. The bar does a good job simulating height, meaning drones seem to fly overhead from clear and accurate locations around you. The lack of low-bass is noticeable, especially with action-packed scenes and high-intensity explosions. It doesn't provide the same immersive feeling as more premium setups like the Bose Smart Soundbar 900 or the Sony HT-A9. But, ultimately, it offers a comparable performance to other Atmos bars in this price range, like the Sonos Beam (Gen 2) and the Vizio M Series M512a-H6.

3.9
Sound
Sound Enhancement Features
Room Correction
No
Dialogue Enhancement
Yes
Auto-Volume/Night Mode
Yes
Subwoofer Level Adjustment
No
Bass Adjustment
Yes
Treble Adjustment
No
EQ
Presets
Surround Level Adjustment
No
Rear Level Adjustment
No
Height Level Adjustment
No
Virtual Surround
No

The selection of sound enhancement features for the Polk Audio Signa S4 is pretty limited. As expected with bars in its price range, you don't find premium sound enhancement features like room correction. There's a dialogue enhancement feature - which Polk calls VoiceAdjust - and it lets you choose between three different volume levels for the voices in your audio. The Night Mode feature is ideal for watching TV at night since it lowers the bass and increases the dialogue's volume to help you hear every word without bothering anyone around you. However, if you want to customize its sound, there aren't many options besides its bass adjustment feature and its two EQ presets: Music and Movie.

Connectivity
Connectivity
Physical Inputs - Bar
Optical Audio In
1
HDMI ARC
1
HDMI Out
No
Full HDMI In
No
Analog Audio In 3.5mm (Aux)
1
RCA In
No
USB for Files
1
Ethernet
No

There's a pretty limited selection of inputs on the Polk S4. You can connect the bar to your TV with its optical or HDMI ARC inputs. You can also play music on the bar from other sources using its 3.5mm AUX input or its USB input for flash drives. However, you won't find an HDMI In port for video passthrough.

8.8
Connectivity
Audio Format Support - ARC
eARC
Yes
Dolby Atmos
Yes
Dolby Digital
Yes
Dolby Digital Plus
Yes
DTS
No
DTS:X (eARC only)
No
Dolby TrueHD (eARC only)
Yes
DTS-HD MA (eARC only)
No
5.1 PCM (eARC only)
Yes

The Polk Audio Signa S4 has excellent audio format support via ARC. It supports some of the most common surround sound formats, including Dolby Digital, and lossless and object-based formats like Dolby Atmos. Unfortunately, there's no support for DTS content.

0
Connectivity
Audio Format Support - Full HDMI In
Dolby Atmos
No
DTS:X
No
Dolby Digital
No
Dolby Digital Plus
No
DTS
No
Dolby TrueHD
No
DTS-HD MA
No
5.1 PCM
No
6.0
Connectivity
Audio Format Support - Optical
Dolby Digital
Yes
DTS
No

Over Optical, the Polk Audio Signa S4 supports Dolby Digital, the most common surround sound format used on Blu-rays and streaming platforms. There's no DTS support, though.

7.0
Connectivity
Latency
ARC
84 ms
Optical
100 ms
Full HDMI In
N/A

The Polk Audio Signa S4 has a decent latency performance. Over ARC, its latency falls just outside of the ideal range, but the audio you hear and the video you see still appears to be in sync. However, its performance isn't as good over an Optical connection. Keep in mind that latency measurements can vary based on several factors, including the TV and the app used, so your experience can vary.

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

The Polk Audio Signa S4 only supports Bluetooth connectivity. You can wirelessly stream audio from your phone or tablet to the bar over Bluetooth.

Connectivity
Other Input Specifications
4k @ 60 Hz Passthrough
No
4k @ 60 Hz @ 10 bit Passthrough
No
4k @ 60 Hz @ 4:4:4 Passthrough
No
HDR10 Passthrough
No
Connectivity
Connectivity - Subwoofer
Sub Wireless
Yes

The sub connects to the bar wirelessly. You just need to plug it into a power outlet to get it to work.

Connectivity
Connectivity - Satellites
Sat Wireless
No
Additional Features
Additional Features
Interface
Display
No

There's no display, but you can find a couple of small lights on the front of the bar that change colors, depending on the settings you use. It's green when playing Dolby Digital content and teal with Dolby Atmos. Also, it turns red when an audio format isn't supported.

Additional Features
Bar Controls

There are a couple of physical controls on top of the Polk S4. You can use them to power it on/off, change the input, activate Bluetooth, and adjust the volume.

Additional Features
Remote
Universal Remote
No

The remote is small and straightforward, providing easy access to all the bar's features. You can adjust the volume, change the input, and add or subtract the amount of bass. The three numbered buttons at the bottom of the remote let you choose between the three levels of dialogue enhancement. Above that, you find the buttons for the Music and Movie EQs as well as the Night Mode feature.

Additional Features
Voice Assistants Support
Amazon Alexa
No
Google Assistant
No
Apple Siri
No
Additional Features
App
App Name No App
iOS No
Android No
Acts As A Remote
No
Controls Soundbar's Settings
No
Casts Device Files
No
Additional Features
Other Features
Power Saving
Standby
HDMI CEC (TV Remote Control)
Yes

The Polk Audio Signa S4 goes into standby mode after 20 minutes of inactivity. You can also use your TV remote to control some of its basic functions since it supports HDMI CEC.

Differences Between Sizes And Variants

The Polk S4 is available in 'Black'. You can see the label for the bar here.

If you come across another version of this soundbar, let us know in the discussions, and we'll update the review.

Compared To Other Soundbars

The Polk Audio Signa S4 is a 3.1.2 setup that offers a more affordable alternative to other Atmos bars on the market. Its Atmos performance is comparable to similarly-priced bars like the Sonos Beam (Gen 2), but it doesn't offer the same immersive sound as more premium setups. There's also a lack of low-bass that takes away from the thump and rumble in movie scores and action-filled scenes, which is a bit unfortunate. If you're on a budget, it's still a fairly versatile bar.

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

Sonos Arc

The Sonos Arc is better than the Polk Audio Signa S4. The Sonos is a 5.0.2 setup with a standalone design, ideal if you don't have a lot of space. Also, it has better soundstage, Atmos, and surround performances than the Polk. It even comes with additional features, like room correction and built-in voice assistant support. You can upgrade it with a sub and satellites down the line if you want.

JBL Bar 5.1 Surround

The JBL Bar 5.1 Surround is a bit better for mixed usage than the Polk Audio Signa S4. The JBL is a 5.1 setup with a better surrounds performance. It can reproduce a more extended low-bass, and it also comes with more sound enhancement features, including room correction. That said, the Polk is still a pretty versatile 3.1.2 setup. It has a better soundstage than the JBL, and it even supports Dolby Atmos content.

Sonos Beam (Gen 2)

The Sonos Beam (Gen 2) is better than the Polk Audio Signa S4. The Sonos is a 5.0 setup with a small, compact design, ideal if you don't have a lot of space. Despite its small size, it has better soundstage and surround performances than the Polk. It also comes with additional features, like room correction and built-in voice assistant support.

Samsung HW-Q600A

The Samsung HW-Q600A is better than the Polk Audio Signa S4. They're both 3.1.2 setups, but the Samsung soundbar can reproduce a more extended low-bass. It also gets louder and has some more sound enhancement features, like a graphic EQ. There's even a Full HDMI In port for video passthrough, unlike the Polk.

Samsung HW-Q800A

The Samsung HW-Q800A is better than the Polk Audio Signa S4. They're both 3.1.2 setups, but the Samsung can reproduce a much more extended low-bass. It also has a better soundstage and more sound enhancement features, like a graphic EQ. There's even a Full HDMI In port for video passthrough, unlike the Polk.

Sony HT-G700

The Sony HT-G700 and the Polk Audio Signa S4 are both 3.1 setups that are ideal for listening to vocal-heavy content like TV shows. The Sony scores better overall, as its surround performance is better. Unlike the Polk, it also supports DTS content. That said, the Polk has a better soundstage.

Samsung HW-Q700A

The Samsung HW-Q700A is better than the Polk Audio Signa S4. The Samsung has better soundstage and surround performances, and unlike the Polk, it supports DTS content. There are also more sound enhancement features available, including a graphic EQ.

Polk Audio MagniFi MAX SR

Depending on your listening habits, you may prefer either the Polk Audio MagniFi MAX SR or the Polk Audio Signa S4. The MAX SR is a 5.1 setup that comes with dedicated satellites, and it has a better surround sound performance. However, it doesn't support Dolby Atmos content like the Signa S4. Also, the MAX SR reproduces a lot of compression and distortion, especially in the bass range, that affects the sound of your audio.

Yamaha YAS-209

Depending on your listening habits, you may prefer either the Polk Audio Signa S4 or the Yamaha YAS-209. The Polk is a 3.1.2 setup that supports Dolby Atmos content, unlike the Yamaha. It also has a better center channel performance. However, the Yamaha reproduces a more extended low bass. It also supports DTS content and has a Full HDMI In port, unlike the Polk.

Vizio M Series M512a-H6

The Vizio M Series M512a-H6 is better than the Polk Audio Signa S4. The Vizio is a 5.1.2 setup with discrete satellites that offers better soundstage and surround performances. It can reproduce a more extended low-bass than the Polk, too. Unlike the Polk, it has DTS support and a Full HDMI In port for video passthrough. If you don't have space for satellites in your room, the Polk is still a fair option with Dolby Atmos support.

Vizio SB36512-F6

The Vizio SB36512-F6 is better than the Polk Audio Signa S4. The Vizio is a 5.1.2 setup with discrete satellites. It has a better surround performance and can reproduce a more extended low-bass than the Polk. Unlike the Polk, it even has a Full HDMI In port for video passthrough. If you don't have space for satellites, the Polk is still a decent choice.

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