Polk Audio Signa S4 review: One of the best bang-for-buck soundbars you can get

While $400 is a pretty chunky amount of money, many of the best soundbars go for double that, if not double again. Enter the Polk Audio Signa S4 soundbar, which offers full 3.1.2 channel Dolby Atmos surround audio, three listening modes, and a patented ‘Voice adjust’ setting.

The three listening modes include cinema mode, which does what it says on the tin, night mode, which reduces bass for late-night listening, and music mode, which can be used for music playback or musical movies.

The Signa S4 has a wireless subwoofer, which only needs to be plugged into a power socket to connect to the soundbar. The external subwoofer makes way for almost ‘true’ Dolby sound, with layered, cocooning bass, and the soundbar’s upfiring speakers do the rest of the legwork. All things considered, $399 is a very reasonable sum for this soundbar + subwoofer combination. So what else can the Signa S4 do? Find out in this full Polk Audio Signa S4 review.

Polk Audio Signa S4 review: Çheat sheet

• What is it? A soundbar + subwoofer combo
• Who is it for? Movie lovers, TV bingers, newbies to the home cinema world
• What does it cost? Seems like a lot but it’s not — $399 / £329. Other hi-fi setupts start from upwards of $1k for a subwoofer + soundbar combo
• What do we like? The excellent sound quality for the price
• What don’t we like? There’s no smart home integration

Polk Audio Signa S4 review: Specs

Polk Audio Signa S4 review: Price & availability

The Polk Audio Signa S4 is just $399 from Amazon U.S. and £329 from Amazon U.K.. This is a fantastic price for a three-channel soundbar with a wireless subwoofer. Polk’s flagship hi-fi system, the Magnifi Max AX SR, with 7.2.1 channel audio, is $899, which would be a good option for a serious home-cinema fanatic.

The Bose Smart Soundbar (2024) is $499 for just the soundbar — the Bose Bass 700 subwoofer will set you back an additional $849. The Sonos Arc Ultra ($999) is one of the best soundbars on the market, with 9.1.4 channel audio. It’ll cost you, though — in that case, the Polk Audio Signa S4 is a great place to start on a budget.

Polk Audio Signa S4 review: Design & controls

At 42 inches long, the Signa S4 isn’t exactly a compact soundbar. The length means you’ll need a big enough TV stand or enough wall space to mount the soundbar — it’s much bigger than the Bose Smart Soundbar 2024’s 27 inches. It couldn’t fit on my small TV stand at home, so I did all my testing in the office testing labs.

Despite the length, though, the Signa S4 is slim, at just 2 inches high. This means the soundbar won’t interrupt the TV remote signal, and should slot nicely underneath large or wall-mounted TVs.

The Signa S4 has three primary speakers (left, center, and right), two upfiring speakers (which bounce sound off the ceiling to create the effect of surround sound), and a subwoofer. The main soundbar contains the three main speakers and two up-firing speakers. Although the pliable fabric mesh casing does not spark joy, the soundbar actually looks really nice. There’s no reason why this soundbar wouldn’t look the part in a home cinema system, despite not being as objectively beautiful as the Sonos Arc Ultra.

The subwoofer’s woofer is on the bottom, so it doesn’t need to be put anywhere specific to be effective. However, Polk advises users to place the subwoofer on the same wall as the soundbar, and no more than 30 feet away.

On top of the soundbar are five buttons: power on, exit, Bluetooth, volume up, and volume down. These buttons are satisfyingly tactile, but I found myself using the remote more. While the Bose Smart Soundbar (2024) remote felt flimsy, the Polk remote is extremely sturdy. As I was hooked up to our Panasonic testing TV via eARC, I could use the TV’s remote for control, and this worked well to change the volume of the soundbar with no latency. When I was testing the Majority Elias soundbar a few weeks ago, it irritated me that the soundbar remote and TV remote did not work in tandem: I could increase the volume with the TV remote and it wouldn’t increase the soundbar volume. This was not an issue with the Polk S4 Signa.

Polk Audio Signa S4 review: Features & setup

Setting up the Polk Audio Signa S4 was super easy. No fiddling with janky Wi-Fi connections or floundering with Bluetooth settings. I simply plugged in the subwoofer, plugged in the soundbar, and connected the eARC HDMI cable to our Panasonic MZ1500 4K OLED testing TV. As discussed earlier, the Signa S4 comes with an optical cable too, but it doesn’t support Dolby Atmos — only way to get the full surround effect is with an HDMI cable.

The Signa S4 is wall-mountable, but I just placed it on a TV stand. The subwoofer connects wirelessly with a toggle at its rear, which reduces the need for more wires and the dreaded cable management.

Once the soundbar was set up, I was able to get stuck into its range of attractive features. As briefly mentioned, the soundbar has a variety of modes: voice adjust (1, 2, and 3), night mode, music mode, movie mode, and a bass/treble volume control.

I tested all of these modes, which I’ll discuss fully in ‘Sound quality’ below. However, it’s worth noting briefly that ‘night mode’ reduces bass, ‘voice adjust’ isolates dialogue and increases its volume to varying degrees, and ‘movie mode’ increases bass for that ground-shaking, cinematic experience.

If you want to listen to music through the soundbar, you can easily connect your device to the Signa S4 using Bluetooth and play from your favorite streaming app.

There are no smart home features on the Polk S4 Signa. Of course you can play music via Bluetooth or hypothetically link up the S4 Signa to a turntable or broader hi-fi setup, but I only tested it as a TV soundbar.

Polk Audio Signa S4 review: Sound quality

To thoroughly test the Signa S4, I watched a variety of movies. I’ll discuss ‘Top Gun: Maverick’ and ‘The Wild Robot’ here. I watched the opening scene of ‘Top Gun: Maverick’ four times using the various different playback modes.

As ‘Top Gun: Maverick’ is our benchmark for testing soundbars, I knew this had to be the first thing I watched. Previously, I’ve watched this movie with the Samsung Q990D soundbar ($1,997) and was blown away by the delicate metallic sound effects and overbearing jet engine notes. So, I was intrigued to hear if the $400 Polk Audio Signa S4 could live up to the Q990D.

Well, short answer: no. But the Signa S4 is still really good for its price. For a sub-$400 soundbar + subwoofer setup, the Signa S4 impressed me beyond belief.

Movie test — Top Gun: Maverick

In the opening scene of ‘Top Gun: Maverick’, I could hear all the low-frequency sounds like the clinking of metal-on-metal and the whipping ropes. The roar of the jet engines was sonorous and all-encompassing, but didn’t overpower the low-frequency sound effects. Yes, the rope sounds could have been clearer — the swooshing was drowned a tiny bit by the jets — but in general, this scene impressed me.

The music — ‘Danger Zone’ by Kenny Loggins, naturally — is a classic track with the ‘80s idiosyncratic gated drums and melodramatic synths. None of this retro bombasticness was lost in the scene, and the Signa S4 performed the dramatics admirably.

Voice adjustment mode

After watching the opening scene of ‘Top Gun: Maverick’ no less than four times, I moved onto the rest of the movie with the aim of testing the ‘Voice adjust settings’. ‘Voice adjust: 1’ didn’t appear to change the sound much, with all of the ambient noises and sound effects still very audible. As promised, the dialogue was clearer and more instantly intelligible. Perhaps there was a little less bass, but I think ‘Voice adjust: 1’ changed the sound the least.

‘Voice adjust: 2’ altered the bass performance massively. When this mode was active, there was very little bass, and the dialogue was certainly clearer thanks to the increased treble. I would recommend this for movies with little action so as not to negatively affect the action scenes.

Finally, I tested ‘Voice adjust: 3’. This vocal mode muffled the bass performance and increased intelligibility of dialogue. Even though this mode made voices easier to discern, the bass performance suffered. Again, I would only recommend this setting for movies without heavy action scenes.

Overall, ‘Voice adjust: 1’ was the best performance, and I would stick to this setting over the over two options.

Movie & Night modes

After testing out the ‘Voice adjust’ settings, I dove into the ‘Movie’ mode. This mode increases bass for that quintessential bombastic cinematic experience. ‘Movie’ mode transformed ‘Top Gun: Maverick’ from just something I was watching in the office into a movie.

The bass vibrated the floor and irritated my coworkers trying to work in the office below (sorry). I will mention, however, that some of the softer ambient sounds were lost in the melee, such as the over-headset speech. I had to really listen to understand some of the softer tones communicated via headset. However, the beeps of controls and jet engines were very loud — actually, sometimes too loud. It all depends on what genre you’re watching or what you’re personally into. Some people will love this all-encompassing bass performance, some won’t. If you want a truly earth-shaking soundbar for relatively little money, then the Polk Audio Signa S4 will not disappoint.

‘Night mode’ reduces bass and also warmth in human voices: it does what it sets out to (be quiet at night time), but it sacrifices audio quality to do it. I would only use this in a pinch, but that’s what it’s there for.

Move test — The Wild Robot

After ‘Top Gun: Maverick’, I watched the DreamWorks movie ‘The Wild Robot’. In a scene which sees a gosling character disappear behind the shot and walking around the main character. This was the first time I noticed the proficiency of the Signa S4’s Dolby Atmos. The gosling’s speech sounded as if it was coming from behind me and really immersed me in the scene.

Later on in the same scene, the gosling swims in a lake. The underwater sound effects were clear and immersive, and again, I really felt like I was in the water with the scene. When the gosling is encircled by goose bullies (it’s a good film, I promise), the jibing dialogue sounded truly 360°, however unpleasant that experience may be.
Overall, the Polk Audio Signa S4 really impressed me. Considering this soundbar + subwoofer combination is under $400, this is a stellar performance, certainly worthy of its 4-star rating. Holding it back is a little audio separation issue,

Polk Audio Signa S4 review: Verdict

While this soundbar doesn’t have the audio finesse of a full hi-fi setup, it’s a heckin’ good start. The $400 soundbar + subwoofer combination makes way for indomitable bass (in movie mode), highly intelligible speech (in ‘Voice adjust: 1’), and immersive Dolby Atmos. You’d be surprised that a 3.1.2 channel setup could be this immersive, but I love to be surprised.

The range of listening modes means any member of the family will be impressed with the sound, whether they’re an action movie fanatic or a documentary lover. On top of that, you can easily use the soundbar for music playback using ‘Music’ mode. While there’s no smart home integration, this wouldn’t be an issue for people like me who don’t have an Alexa or Google Assistant setup anyway. For just $400, the Polk Audio Signa S4 is an excellent choice. Snag this while you can.