Polk Audio S20 Signature Series Review

Many people who are thinking of buying speakers for their home ask the same question, “should I get a floor-standing speaker or a bookshelf speaker?”

Typically, floor-standing speakers, also known as tower speakers, are larger in size and therefore take up more space. This can be a challenge for some folks who do not have space to spare for the bigger floor-standing speakers.

Bookshelf speakers provide a smart alternative. They’re compact and can be placed on the furniture, a bookshelf, or wall-mounted to save space. When talking about bookshelf speakers, this Polk Audio S20 Signature Series review, definitely prompts the S20 as a serious contender.

If you’ve already decided on the Polk Audio S20 Signature , check it out on Amazon here.

If you’re still not sure, this review will give you all the information you need to decide whether the Polk Audio S20 Signature is right for you. And if it doesn’t quite fit the bill I’ve added some alternatives you might consider.

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What to Consider Before Buying the Polk Audio S20 Signature Speaker?

Since the smaller form factor usually means that bookshelf speakers come with low-end bass, investing in a good quality bookshelf speaker can get you the right balance between excellent sound and a compact design

When you’re looking to purchase a bookshelf speaker, the first thing you need to know is the size of the listening area, as in, how large or small the room is where you’re going to place the speakers.

While large rooms will need a large size speaker, such as floor-standing options, to fill the room, smaller spaces do not require floor-standing speakers because their sheer size works against them when placed in tiny rooms.

However, small to medium-sized rooms are where bookshelf speakers shine. In fact, that’s the reason why the compact bookshelf speakers exist in the first place; as a viable alternative to the larger floor-standing speakers, otherwise known as tower speakers.

Some of the many benefits of investing in a good quality bookshelf speaker such as the Polk Audio S20 Signature speakers is that they boast:

  • Flexible placement
  • Smaller footprint
  • Integrates into a home theater system
  • Costs less (as compared to floor-standing speakers)

When it comes to sound quality, bookshelf speakers have come a long way from their predecessors.

Nowadays, many brands are using technologies that have been custom-made to fit in the portable bookshelf speaker to improve sound quality. This solves the problem for people who think that the bookshelf speaker isn’t up to scratch when compared to floor-standing speakers.

In fact, you will find, in many areas, compact bookshelf speakers such as the Polk Audio S20 Signature speakers outperform tower speakers when used in smaller spaces.

Another reason to consider getting bookshelf speakers is if you prefer that traditional stereo sound. Since bookshelf speakers have been designed to be a part of a more extensive sound system (if needed), these speakers have been equipped with technologies that enable exceptional mid-range and bi-directional sound.

This also happens to make bookshelf speakers an excellent choice for those who prefer stereo sound, or a stronger mid-range.

Presenting the Polk Audio S20 Signature Speaker

It’s no surprise that the Polk Audio S20 Signature speakers pack a punch on the bass and mid-range, even at higher frequencies. The company first opened a shop back in 1972 and has been engineering reliable speakers for decades.

The overall design philosophy of Polk Audio hearkens back to the company’s rich history of designing speakers that are an ode to form and function. The Polk Audio S20 Signature speakers are no different; in fact, it wouldn’t be wrong to say that the S20 Signature takes Polk Audio’s speaker design prowess to a whole new level.

The thought put into the design of these bookshelf speakers is apparent with its non-resonant MDF cabinet, which features five-way gold-plated binding posts and anti-diffraction magnetic grilles to minimize sonic interferences. Go beyond the sleek, sophisticated surface, and what you get is even more rewarding.

The Polk Audio S20 Signature speakers have quite a few surprises up their sleeve – surprises which enable these speakers to deliver superior sound quality with minimal effort, despite the compact shape.

Pros of the Polk Audio S20 Signature Series

  • Polk’s patented Power Port technology
  • 6.5-inch driver
  • One-inch Terylene tweeter dome
  • Dynamic balance designed acoustic array
  • Vinyl finish in two colors

Cons of the Polk Audio S20 Signature Series

  • Washed-wood MDF cabinet looks flimsy
  • Some might find the sound too thin

Let’s have a closer look at the Polk Audio S20 Signature speaker.

Out-of-the-Box, Cabinet is Designed to Exhibit Low Resonance

The Signature Series sports Polk’s top-shelf components, which is a major highlight of these bookshelf speakers. But, another reason to get the Polk Audio S20 Signature speaker is its well thought of design, which is evident right out of the box.

The Polk S20 sports a sleek, statuesque speaker cabinet, which easily towers above many other bookshelf speaker options available in the market today.

While Polk did go with a real wood veneer for the speaker cabinet this time around, its sleek, cardboard cabinet coupled with an attractive curvy frame does make for a dramatic presence wherever the S20 is placed.

The non-resonate Medite MDF construction coupled with extra bracing and thicker baffles makes these speakers look top-shelf right out of the box. The inclusion of the intense walnut vinyl veneer also gives it a premium quality look, which will pretty soon make you forget that the cabinet is not wood.

If you’re looking to make a style statement or spruce up things, just remove the magnetic screens to reveal the splash of golden-pearl finishing on no less than three woofers, which also gets major style points.

With the Polk Audio S20 Signature speaker, it’s easy to see that Polk focused just as much on the style of its new lineup of bookshelf speakers as it has on its innards, and that’s a good thing.

Large 6.5” Bass Driver Features Mica-Reinforced Polypropylene Cone Let’s in More Air for Better Efficiency

Moving away from the drama outside, makes you realize that the Polk Audio S20 Signature speakers offer stunning features that make these bookshelf speakers stand out from the crowd.

The S20 sports a sizeable 6.5-inch driver, which boasts a mica-reinforced polypropylene cone. This feature allows a considerable amount of air to enter into the driver, which, in turn, results in better efficiency.

With this small design tweak, it seems like Polk Audio is following the basic principles of speaker design, which states that drivers require more air to benefit from a better extension on the lows. All this improves its efficiency.

As a result, the S20 delivers an exceptional frequency response, which can reach down to 39Hz on the low side. Speaking of the S20’s ability to produce low frequencies, these speakers also have a Power Port vent, which is smartly placed behind the speakers. It is explicitly designed to ensure optimal direction while dealing with low frequencies.

One-Inch Polyester Dome Tweeter Provides Greater Dampening along with Soft Restitution for High Frequencies

Another smart feature in the Polk Audio S20 Signature speaker is its uniquely designed dome tweeter, which measures at 1-inch and is made from high-quality polyester.

The shape of this dome tweeter means it delivers far superior dampening as compared to many other bookshelf speakers, along with soft restitution when it comes to higher frequencies. This certainly gives the Polk Audio S20 Signature speakers an edge over many other bookshelf speakers at the same price point.

Not to forget, the S20 is certified for Hi-Res Audio, which means the frequency response can extend all the way to 40 kHz. The S20 sports a sensitivity rating of 88 DB at 1 kHz. This is excellent for a bookshelf speaker. That said, the response curve has not been provided by the company.

Advanced Atmos Configuration Ensures Dynamic Balance

Another standout feature in the S20 is the integration of the advanced Atmos configuration, which ensures dynamic balance when producing a full range of sound.

This patented technology is used to analyze the full mechanical and electro-acoustic system. By identifying efficiency issues in the various components in the speaker, it helps improve overall speaker performance.

Features Polk Audio’s Patented Power Port Deep Bass Technology

The Polk Audio S20 Signature speakers also sport the exclusive Power Port Deep Bass Technology, which is patented by Polk Audio and gives an edge to these bookshelf speakers.

The patented design allows a smooth transition in the airflow from the port to the listening area. This allows the speakers to extend the bass port with a greater surface area, which does away with any distortion or turbulence in the sound quality when playing low frequencies.

What sets Polk Audio’s Power Port Deep Bass Technology apart from the rest is that it provides 3dB of more bass output as compared to traditional bookshelf ports.

What Do Buyers Say?

The modern styling and stunning black walnut finish have been much appreciated by fans of Polk Audio.

But, what’s long been recognized with the Polk Audio S20 Signature speakers is the smart blend of components that enables the S20 to achieve seamless speaker-to-speaker blending effects when used with multi-channel systems.

Consumers have lauded the fact that the Polk Audio S20 Signature speaker shines when worked together with even the most modestly powered amplifiers or receivers, which is also another plus point of the S20.

Some buyers have said that calling the S20 as bookshelf speakers is a stretch because they are large, with a depth that could be a challenge fitting into a number of bookshelves. This might be the only reason you don’t buy the Polk Audio S20.

Any Alternatives to the Polk Audio S20 Signature Speaker?

Here are some other options to the Polk Audio S20 Signature Speaker you might take a shine to.

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  • 5.25-inch woofer
  • 1.1-inch dome tweeter
  • Remote control
  • Max Power Input: 120 watts

The Swans M200MKIII Powered 2.0 Bluetooth Bookshelf Speaker is worth considering as an alternative to the S20. These speakers have been exquisitely designed to fit nicely in any living space. 

These bookshelf speakers boast a powerful 5.25-inch mid-bass driver along with a 1-inch silk dome tweeter, which blends the sound well, resulting in rich quality high, mid, and low frequencies.

Check out the Swans M200MKIII Powered 2.0 Bluetooth Bookshelf Speaker on Amazon here.

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  • 5.25-inch fiberglass woofer
  • 1-inch soft-dome tweeter
  • Max Power Input: 50 watts

If you’re looking for stable build quality in a bookshelf speaker, but are ready to skimp on the power, then the Peachtree Audio M25 Powered Speakers are just what you need.

While these speakers do not provide the rich range of sound as the S20, they are attractive to look at and make a great style statement, while delivering a decent sound quality.

Check out the Peachtree Audio M25 Powered Speakers on Amazon here.

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  • 5.5-inch woofer
  • Nominal Impedance: 4, 6, and 8 ohms
  • Max Power Input: 150 watts

The Audioengine HDP6 Passive Bookshelf Speaker is another excellent alternative to the Polk Audio S20 Signature Series bookshelf speakers. These speakers pack a big sound that can quickly fill up a medium-sized room.

The speakers are constructed with custom Audioengine components such as the silk tweeters and Aramid fiber woofer that comes in a hand-crafted cabinet, offering a premium quality product.

Check out the Audioengine HDP6 Passive Bookshelf Speakers on Amazon here.


Like many other Polk Audio speakers, the S20 speakers are passive bookshelf speakers, which basically means they are going to need a receiver.

But, this is certainly not going to be a deal-breaker considering the amount of attention to detail that’s been put into the design and the components of the Polk Audio S20 Signature speakers.

One thing that’s evident right out of the box is the premium quality build of this speaker. The smart configuration of components, such as the large, 6 ½ inch woofer and Terylene dome tweeter, along with the Power Port bass vent, makes these speakers worth every penny.

To check out the Polk Audio S20 Signature Series on Amazon, click here.

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