Polk Audio Signa S4 Review: Top Sound Bars Performance Analysis

Polk Audio Signa S4 Technical Review: A Masterclass in Accessible Cinematic Immersion

Introduction: The Sonic Revolution Your Living Room Deserves

In the golden age of high-definition streaming and 4K visual fidelity, a glaring paradox has emerged in home entertainment: our televisions have become stunningly beautiful windows into other worlds, yet their built-in audio remains trapped in a flat, lifeless reality. The impossibly thin profiles of modern TVs, while aesthetically pleasing, defy the laws of physics required to produce rich, dynamic, and immersive sound. This sonic compromise shatters the very illusion the visuals work so hard to create, leaving explosions without impact, dialogue without clarity, and epic scores without grandeur. It is this fundamental problem that the Polk Audio Signa S4 TV Sound Bar with Subwoofer is engineered to solve, not just as an incremental upgrade, but as a complete and transformative audio overhaul for your home theater.

The Signa S4 is not merely a louder speaker for your TV; it is a sophisticated, multi-driver audio system designed to bring the three-dimensional, object-based sound of a modern cinema directly into your living room. Polk, a brand with a storied heritage in high-performance audio, has strategically integrated the revolutionary Dolby Atmos technology into an accessible, user-friendly package. This is not a virtualized or simulated effect; the S4 is a true 3.1.2-channel system with dedicated up-firing speakers that physically create the overhead dimension of sound, a hallmark of the Atmos experience. This core technology is supported by a suite of Polk’s proprietary innovations, like VoiceAdjust for crystal-clear dialogue and BassAdjust for customizable low-end impact, all anchored by a powerful wireless subwoofer. It is a system designed to excel not just in bombastic movie moments, but in every aspect of your daily viewing, from a quiet drama to the nightly news.

In this exhaustive, technical review, we will perform a deep dissection of the acoustic engineering and digital processing that define the Signa S4. We will deconstruct the science of its 7-driver array, explain the profound impact of its discrete height channels, analyze the functionality of its patented voice clarity technology, and demystify the critical role of HDMI eARC in delivering a pristine, high-resolution audio signal. This is a granular analysis for the discerning consumer who wants to understand not just the “what” but the “why” and “how” behind a truly immersive sound experience, and to discover why the Polk Signa S4 stands as a top-tier contender for the best value in cinematic home audio today.

A Deep Dive into the Key Features: A Technical Dissection of Acoustic and Digital Excellence

The Signa S4’s position as a market leader in its class is not due to a single feature, but rather the synergistic integration of advanced acoustic design and intelligent digital signal processing (DSP). Let’s analyze each core component from a technical perspective to understand its impact on the overall performance.

• True 3D Surround Sound: Deconstructing the 3.1.2 Dolby Atmos Driver Array

  The headline feature of the Signa S4 is its certification for and physical implementation of Dolby Atmos. This is not a virtual or simulated surround sound; it is a true 3.1.2-channel system. Let’s break down this nomenclature:

  • 3: Represents the three main forward-facing channels: Left, Center, and Right.
  • .1: Represents the Low-Frequency Effects (LFE) channel, handled by the dedicated wireless subwoofer.
  • .2: Represents the two dedicated height channels, which are the cornerstone of the Dolby Atmos experience.

  This is achieved through a sophisticated 7-driver array within the ultra-slim soundbar. The array consists of left and right channels, each composed of a 0.98″ tweeter for crisp high-frequencies and a 4.7″x1.57″ racetrack-shaped mid-range driver. The racetrack shape is an intelligent engineering choice, providing a larger surface area than a conventional round driver of a similar height, which allows it to move more air and produce a richer, fuller mid-range sound from a slim enclosure. Critically, there is also a dedicated 0.98″ full-range center channel driver. Its sole purpose is to reproduce dialogue, a crucial design choice for clarity. The final two drivers in the array are the left and right 2.59″ up-firing elevation speakers. These drivers are physically angled to bounce sound waves off your ceiling and back down to your listening position. When a Dolby Atmos signal is detected, the processor sends specific “audio objects”—like the sound of a helicopter, falling rain, or a soaring musical score—exclusively to these speakers. This creates a true “height elevation” effect, generating an immersive 3D sound bubble that extends over your head, a feat that traditional 5.1 or 7.1 channel-based surround sound cannot replicate. The powerful 5.9″ wireless subwoofer completes the system, providing the deep, impactful bass that creates a “wide soundstage” and lends weight and scale to the entire cinematic experience.

  

• Crystal-Clear Dialogue: The Science of Polk’s Exclusive VoiceAdjust Technology

  One of the most common complaints about home theater audio is that dialogue gets lost amidst loud background music and explosive sound effects. This forces viewers to constantly “ride the volume,” turning it up for conversations and then rushing to turn it down during action scenes. Polk’s patented VoiceAdjust technology is the definitive solution to this problem. This is far more than a simple equalizer. It is an intelligent form of digital signal processing that specifically targets and isolates the frequency range of the human voice. Critically, it works in concert with the Signa S4’s dedicated physical center channel driver.

  When you use the remote to increase the “Voice” level, the technology allows you to independently raise the volume of *only the center channel*, without affecting the volume of the left, right, or subwoofer channels. This allows you to “adjust voice levels to hear clear dialog without missing a word.” You can make speech cut through the mix with pristine clarity, even during the most chaotic action sequences. This level of granular control is a game-changer for viewing enjoyment, ensuring you are always connected to the narrative and characters. This is further complemented by the Bass Adjust Technology, which allows for independent control of the low-frequency output, giving you the power to dial in the perfect amount of rumble for maximum impact or to tone it down for late-night viewing without sacrificing overall sound quality.

  

• Pristine Signal Path: The Importance of HDMI eARC Connectivity

  The Signa S4’s ability to deliver a true, high-fidelity Dolby Atmos experience is made possible by its inclusion of an HDMI eARC port. eARC stands for Enhanced Audio Return Channel, and it is a critical feature for any modern soundbar. A standard ARC port has enough bandwidth to carry compressed audio signals, like standard Dolby Digital 5.1. However, the highest quality, lossless audio formats—such as Dolby TrueHD (the format used for Dolby Atmos on 4K Blu-rays) and DTS-HD Master Audio—require significantly more bandwidth. This is where eARC becomes essential.

  The eARC connection provides a high-speed, high-bandwidth pipeline that allows your TV to send these full, uncompressed audio signals to the soundbar. This ensures that you are hearing the audio exactly as the sound engineers created it, with no compression or data loss. The setup is elegantly simple: you connect all your devices (like a 4K Blu-ray player or gaming console) to your TV’s other HDMI inputs, and then run a single HDMI cable from your TV’s eARC port to the Signa S4’s eARC port. The TV then passes through the highest quality audio from any source. This makes the system fully compatible with “any TV including the latest 8K Ultra-HD sets.” This simple, “1-cable setup” not only simplifies your home theater wiring but also guarantees a pristine, high-resolution signal path, which is the foundation of high-fidelity audio.

  

• Unobtrusive and Elegant Design

  A soundbar should enhance the viewing experience, not detract from it. The Signa S4 is designed with a sleek, ultra-slim profile, standing at just 2.36 inches in height. This low profile is a critical ergonomic consideration. It allows the soundbar to be placed on a media console directly in front of most modern televisions without blocking the bottom edge of the screen or, more importantly, the TV’s infrared (IR) remote sensor. This eliminates the frustrating scenario of having to lift your TV remote up high to get a clear line of sight. The clean, minimalist design with its fabric grille and subtle branding allows it to blend seamlessly into any decor. It also includes integrated keyhole slots for easy wall-mounting, providing flexible placement options. This thoughtful, unobtrusive design ensures that the focus remains where it should be: on the stunning picture and the immersive sound.

  

Pros: The Undeniable Technical Strengths

• True Dolby Atmos Immersion: The 3.1.2-channel configuration with discrete, up-firing height speakers delivers a genuine, object-based 3D audio experience, not a virtualized one.
• Exceptional Dialogue Clarity: Polk’s patented VoiceAdjust technology, combined with a dedicated center channel, is a class-leading solution for ensuring speech is always crisp and intelligible.
• High-Fidelity Connectivity: The inclusion of HDMI eARC guarantees a high-bandwidth, uncompressed signal path for the best possible audio quality from all modern sources.
• Powerful, Flexible Bass: The dedicated wireless subwoofer provides deep, impactful low frequencies, and the BassAdjust technology allows for easy user customization.
• Superior Acoustic Design: The 7-driver array with specialized tweeter, racetrack mid-range, and full-range center drivers provides a rich, detailed, and well-balanced sound profile.
• User-Friendly and Unobtrusive: The ultra-slim design prevents screen/IR sensor blockage, and the simple 1-cable setup makes it incredibly easy to install and use.
• Excellent Value Proposition: Delivers a level of performance and a suite of premium technologies that are typically found in much more expensive soundbar systems.

Cons: Important Technical Considerations and Limitations

• No DTS:X or DTS Virtual:X Support: The soundbar is optimized for the Dolby ecosystem and does not include decoding for competing DTS immersive audio formats.
• Limited HDMI Inputs: The Signa S4 features a single HDMI eARC port and no additional HDMI inputs. This means all source devices must be connected to the TV, which then passes the audio to the soundbar. It cannot act as an HDMI switcher.
• No Wi-Fi Connectivity or Smart Features: The soundbar relies on Bluetooth for wireless music streaming. It does not have Wi-Fi, which would be required for features like Chromecast, AirPlay 2, or integration with voice assistants for music streaming.
• Basic Sound Mode Selection: While it offers presets for Movie, Music, and Night modes, it lacks more advanced EQ customization or room correction features found on high-end models.

Conclusion: The Definitive Choice for Accessible Cinematic Audio

The Polk Audio Signa S4 is a masterfully executed product that represents a watershed moment for accessible home theater audio. It succeeds by brilliantly focusing on the core technologies that deliver the most tangible and impactful improvements to the viewing experience. Polk has not diluted its efforts by chasing superfluous features; instead, it has delivered a technically superb and acoustically powerful system that excels at its primary mission: to create a truly immersive, three-dimensional, and dialogue-clear soundstage. The decision to implement a true 3.1.2-channel Dolby Atmos system with physical up-firing drivers is a testament to the brand’s commitment to authentic performance over marketing gimmicks. This is supported by genuinely useful, patented technologies like VoiceAdjust, which solves one of the most persistent problems in home audio, and future-proof connectivity with HDMI eARC.

While it forgoes some of the advanced connectivity and processing of flagship models, the Signa S4 makes no compromises on the core sonic experience. It delivers a level of immersion, clarity, and low-frequency impact that is simply stunning for its class. For the film lover, the streaming enthusiast, or the casual gamer who wants to elevate their TV’s audio from a flat, lifeless whisper to a powerful, cinematic roar, the Polk Signa S4 is not just a good choice—it is the definitive choice. It has rightfully earned its place as a top-tier contender by providing an unparalleled combination of performance, simplicity, and value.

Frequently Asked Questions (FAQs)

Q1: What is the technical difference between Dolby Atmos and traditional 5.1 surround sound?

A: Traditional 5.1 surround sound is “channel-based.” Sounds are assigned to one of six specific speaker channels (front left/right/center, surround left/right, and subwoofer). Dolby Atmos is “object-based.” Sounds are treated as individual objects that can be placed and moved anywhere in a 3D space, including overhead. The Signa S4’s up-firing speakers are what allow it to reproduce this overhead dimension, creating a much more immersive and realistic sound bubble.

Q2: Do I need a special TV with eARC to use this soundbar?

A: For the absolute best performance, a TV with an HDMI eARC port is recommended. This will allow you to pass uncompressed Dolby Atmos signals. However, the Signa S4 will also work with a TV that has a standard HDMI ARC port. With ARC, you can still get Dolby Atmos, but it will be a compressed version (Dolby Digital+), which is what streaming services like Netflix use. The soundbar also has an optical input for older TVs without ARC.

Q3: My ceiling is very high and vaulted. Will the up-firing speakers still work?

A: The effectiveness of the up-firing speakers is best with a flat, reflective ceiling at a standard height (typically 8 to 12 feet). With very high or angled (vaulted) ceilings, the reflection effect will be diminished, and the sense of overhead sound may be less pronounced. However, you will still benefit greatly from the excellent 3.1-channel forward-facing soundstage.

Q4: Is the wireless subwoofer difficult to set up?

A: No, it is designed to be incredibly simple. The subwoofer automatically and wirelessly pairs with the soundbar when both are powered on. You simply need to plug the soundbar and the subwoofer into their respective power outlets. Since it’s wireless, you have the flexibility to place the subwoofer anywhere in the room (within about 30 feet) to find the spot that provides the best bass response.

Q5: What is VoiceAdjust and how is it different from just turning up the center channel volume?

A: VoiceAdjust is Polk’s proprietary technology that allows you to do exactly that—independently control the volume of the dedicated center channel. On many simpler systems, you can only change the overall volume. VoiceAdjust lets you boost the dialogue levels by several steps, making voices cut through the mix without making the explosions and music louder, which is a much more precise and effective way to achieve clarity.

Q6: Can I connect my phone to the Signa S4 to play music?

A: Yes. The Signa S4 features built-in Bluetooth connectivity. You can easily pair your smartphone, tablet, or computer to the soundbar and wirelessly stream music, podcasts, or any other audio directly to the system.

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