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Polk Audio S20 Review
Polk S20 - Image 1

Main Features

  • 1" Soft-Dome Tweeter
  • 6.5" Mica-reinforced polypropylene Woofer
  • 39-40k Hz Frequency Response
  • 88 dB Sensitivity
  • Impedance: 8ohms
  • Power Range: 20-125 watts
  • Weight: 17.01 lbs / 7.73 kg
  • Dimensions(HxWxD): 14.8"x8.5"x13.7" / 376.0 x 216.0 x 350.0mm
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Polk S20 Review
Polk S20 Polk S20
Check price atAmazon›

Polk Audio Signature S20 is a 2-way Passive Bass Reflex Bookshelf speaker by Polk Audio. It was released in September 2016. It features a 1" Soft-Dome Tweeter and 1 x 6.5" Mica-reinforced polypropylene Woofer. The speaker has a frequency range of 39-40k Hz and a sensitivity of 88 dB.

Room Size Suitability

The size of the room where you plan to use the Polk S20 is a crucial factor in your decision. We have assessed its suitability for various room sizes based on its dimensions and maximum power output:

Listening Environment* Suitability
Near-fieldPoor
Small RoomAverage
Mid-size RoomGood
Large RoomAverage
Very Large RoomPoor

(* Approximate Room sizes: Small < 100sq. ft / 9 m2, Mid-size: 100-220 sq. ft / 9-20 m2, Large 220-400 sq. ft / 20-36 m2, Very Large: > 400 sq. ft / 36 m2. Average Floor Height: 9" / 2.7m. Typical room sizes differ from country to country, and the actual listening experience changes depending on floor height, room shape, surface materials, listening position, speaker locations, etc.)

Polk Audio later replaced S20 with ES20. Follow the link to read our in-depth comparison of these speakers:
Compare Polk S20 vs Polk ES20

Polk Audio's Signature S Series of Loudspeakers

S20 is a member of Polk Audio's Signature S series of Passive speakers. The Signature S range was Polk Audio's affordable line of home-theatre and hi-fi speakers. Below you can see the main specs of these speakers.

See all 6 Polk Audio Signature S models compared »

Polk Audio Signature S Series Speakers
Model Frequency SensitivityImpedance Woofer
Polk S60
Compare
26-40k Hz 90 dB8Ω 3 x 6.5"
Polk S20
39-40k Hz 88 dB8Ω 1 x 6.5"
Polk S15
Compare
50-40k Hz 88 dB8Ω 1 x 5.25"
Polk S55
Compare
32-40k Hz 90 dB8Ω 2 x 6.5"
Polk S10
Compare
67-40k Hz 87 dB8Ω 1 x 4"
Polk S50
Compare
33-40k Hz 89 dB8Ω 2 x 5.25"
Polk Audio Signature S Series Speakers
Polk Audio Signature S Series Speakers


**This post contains affiliate links, and we will be compensated if you make a purchase after clicking through our links. As an Amazon Associate I earn from qualifying purchases.

Frequency Response of the Polk S20 Speaker

Polk S20 has a Frequency response range of 39-40k Hz and Power Range of 20-125 watts. With a minimum frequency of 39 Hz, S20 delivers deep bass that will likely satisfy most listeners, especially those who enjoy music. However, movie enthusiasts and music fans who prefer a full range of sound may still benefit from adding a subwoofer.

Here we have a comparison of how S20's Low frequency value compares with the average, max and min Low frequency values in its class.
Low Frequency
Bookshelf Speakers
Polk S20
Min
Average
Median
Thinking about a subwoofer for the Polk S20?
  • Work out the crossover setting — it follows from this speaker's 39 Hz low end
  • Every powered subwoofer we cover, whatever the budget

Crossover frequency of the Polk S20?

The crossover frequency of the S20 is set to 2500Hz. This is the threshold frequency where the higher frequency signals over this level are sent to the tweeter and the lower-frequency signals are sent to the woofer by the crossover component.

Polk S20 driver frequency bands39-2.5kWoofer 6.5"2.5k-40kTweeter 1"20501002005001k2k5k10k20k40kHz, log scale

Impedance and Sensitivity

Polk S20's nominal impedance level is 8 ohms and has a sensitivity of 88 dB.

Sensitivity
Bookshelf Speakers
Polk S20
Min
Average
Median

8 Ohms is pretty much the standard nominal impedance amongst stereo speakers and amplifiers so Polk Audio Signature S20 is not considered a difficult to drive speaker from nominal Impedance perspective.

Sensitivity

88dB of the Polk Audio Signature S20 is an average sensitivity for stereo speaker so it is neither easy nor difficult to drive Sensitivity wise. Work out how loud the Polk S20 plays in your room →

What amplifier does the Polk S20 need?

At normal listening levels in a medium room, about 12–125 W per channel into 8 ohms. Set your own conditions and we will rank every amplifier we cover.

We check power, impedance safety and current delivery — not just watts.

Prefer to browse? See every integrated amplifier we cover.

Input Type

S20 features 5-way post type connectors. Bi-amping and Bi-wiring are not possible.

Work out what gauge speaker cable this run needs →

Polk S20 External Dimensions and Weight

Polk S20 has external dimensions of (Height x Width x Depth) 14.8 x 8.5 x 13.7inch (376.0 x 216.0 x 350.0mm ).

Base Surface Area
Base surface area of a loudspeaker may become a determining factor when the space in your room or desk is limited. The base area of Polk S20 is approximately 756.0cm2 / 117.2inch2.

To get a better perspective on the real life size of Polk S20, let's compare it with a standard size Compact Disc which has a diameter of 4.7inch (120mm).

Polk S20 Real Life Body Size Comparison
Polk S20 Speaker Size Compared to a Compact Disc

Here we place the Polk S20 virtually next to a standard width amplifier and turntable on a BDI Octave Media Cabinet to get a better idea about the size.

Polk S20 placed next to an amplifier and turntable
Polk S20 Speaker next to an amplifier and turntable

Find speakers that fit your shelf or alcove →  ·  Work out where they should sit in the room →

Weight

The Polk S20 weighs 7.73kg / 17lbs per piece. Here is a comparison of how S20's weight compares with the average, max and min weights in its class.

Weight
All Bookshelf Speakers
Polk S20
Min
Average
Median

Cabinet type and Materials

Polk S20 has a Bass Reflex type cabinet and a Meddite MDF finish. Bass Reflex type loudspeakers (aka Ported, Vented or Reflex Port) have enclosures that uses a port, hole or vent cut into the cabinet. Ported designs are generally more efficient than the Sealed designs.

Speaker Feet

Polk S20 comes with 8 Self-adhesive rubber feet which you can use to secure your loudspeaker on the surface that you are putting on.

It is always recommended to use some kind of feet under all types of speakers. Besides limiting the movement of the speakers, it also compensates for non-flat surfaces and limits the contact surface area of the speaker. Rubber based feet also help isolating the vibrations within certain frequency ranges.

Port Position

Polk S20 is a rear-firing port speaker so you have to make sure you leave enough space between the back of the speaker and wall or bookshelf so that it has room to breathe.

Available colors

Polk S20 is available in Black, Walnut and Brown Walnut.

Wall Mounting

S20 doesn't sport any built-in mounting bracket, so you need an external structure to mount it on walls.

Does the Polk S20 come with a Grille?

S20 comes with grilles. The purpose of the grille is to protect the delicate driver elements from external impacts while still allowing the sound to pass as clearly as possible.

What's in the Box of Polk S20?

Here are the items that are included inside the box of S20:
  • 2 Bookshelf loudspeakers
  • 2 Grilles (attached)
  • 8 Self-adhesive rubber feet
  • Owners Manual
  • Online Product Registration

Recommended Accessories

Here is a list of accessories that we think you may need for the Polk Audio Signature S20.

  • Speaker Cable and Connectors
    • Speaker Cables with Banana Plugs: If you know the lenght of the cable you need, this is the easier option to connect your speakers with your amp.
    • Speaker Cables without Connectors: If you are not sure about the lenght or need longer than standard cables with plugs, choose this option.
    • Banana Connectors and Plugs: If you chose the cables without connectors option or already have some cable around, pick the banana plugs separately.
  • Vibration Isolators: IsoAcoustics isolators are our favorite isolators but you may find more affordable options too.
  • Acoustic Panels and Treatments: Your room is as important as your stereo equipment so acoustic treatments goes a long way in improving the overall performance.
  • Speaker Stands: Stands bring your bookshelf speakers to ideal height (rule of thumb is to have the tweeter level with your ear in your listening position), helps stability and acoustical isolation.

User's Manual

For more information about how to setup, use and maintain the Polk Audio Signature S20, use the direct link below to download the official manual document:
Download User Manual for Polk S20

Official Brochure

Here is a link to download the official brochure for the Polk Audio Signature S20 speaker:
Official Brochure for Polk S20

Official Product Page

Official manufacturer's product page for the Polk Audio Signature S20 speaker can be found below:
Official Product Page for Polk S20

Warranty

5 Years of parts warranty and 5 Years of labor warranty is generally provided by the manufacturer.

Polk Audio Signature S20 Alternatives in Passive Bookshelf Speakers
Model Type Sensitivity Impedance Frequency
Polk ES20
Compare
2-way 86 dB 8 ohms 41-40k Hz
ELAC Debut 2.0 B6.2
Compare
2-way 87 dB 6 ohms 44-35k Hz
Polk S15
Compare
2-way 88 dB 8 ohms 50-40k Hz
Q Acoustics 3030i
Compare
2-way 88 dB 6 ohms 46-30k Hz
Klipsch RP-600M
Compare
2-way 96 dB 8 ohms 45-25k Hz
Q Acoustics 3020i
Compare
2-way 88 dB 6 ohms 64-30k Hz
Polk RTi A3
Compare
2-way 89 dB 8 ohms 50-26k Hz
KEF Q150
Compare
2-way 86 dB 8 ohms 51-28k Hz
Frequently Asked Questions about Polk Audio Signature S20

What amplifier do you need for the Polk S20?

Polk Audio rates the Polk S20 for 20-125 watts of amplifier power. It is an 8-ohm speaker, the usual nominal load, so almost any amplifier or receiver can drive it.

Is the Polk S20 easy to drive?

The Polk S20 has a sensitivity of 88 dB. That is about average for a home speaker, so it is neither hard nor especially easy to drive.

Does the Polk S20 need a subwoofer?

The Polk S20 reaches down to 39Hz (full range 39-40k Hz). That is deep enough that many listeners will not feel the need for a subwoofer with music.

What drivers does the Polk S20 use?

The Polk S20 is a 2-way design using a 1" Soft-Dome tweeter and a 6.5" Mica-reinforced polypropylene woofer.

Is the Polk S20 sealed or ported?

The Polk S20 uses a Ported enclosure. A ported design uses a tuned vent to get more low-end output from the same driver, but it wants some breathing room behind it.

Can the Polk S20 be bi-wired or bi-amped?

No. The Polk S20 has a single pair of terminals, so bi-wiring and bi-amping are not possible. It uses 5-way post terminals.

Can the Polk S20 be wall mounted?

The Polk S20 does not include a wall-mount bracket or keyhole, so it is designed to sit on a stand, shelf or the floor.

Does the Polk S20 come with grilles?

Yes. The Polk S20 comes with removable grilles.

How big and heavy is the Polk S20?

The Polk S20 weighs 7.73kg / 17lbs each and measures 14.8 x 8.5 x 13.7inch (HxWxD).


Polk S20 Detailed Specifications

General
BrandPolk Audio
Full Model NamePolk Audio Signature S20
Speaker Type2-way Bookshelf
Power Range20-125 watts
Sensitivity88 dB
Impedance8 ohms
Frequency Response39-40k Hz
Release DateSeptember 2016
DRIVERS
Woofer Size6.5-inch
Woofer CompositionMica-reinforced polypropylene
Woofer SurroundButyl rubber
Tweeter Size1-inch
Tweeter TypeSoft-Dome
Crossover freq2500Hz
Port Positionrear

CONNECTIONS
Connector Type5-way post
Biamp InputsNo
Port Positionrear
PHYSICAL SPECS
Height376.0mm ( 14.8-inch)
Width216.0mm ( 8.5-inch)
Depth350.0mm ( 13.7-inch)
Height376.0mm ( 14.8-inch)
Weight7.73 kg (17 lbs)
EnclosureBass Reflex
FinishMeddite MDF
Available ColorsBlack, Walnut, Brown Walnut
Mounting BracketNo
Recommended Stand Height24-28
GrilleYes
Moisture ResistanceNo
OTHER
Handheld RemoteNo
Parts Warranty5 Years
Labor Warranty5 Years
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