In this review, we will be comparing S20 and EVO4.2, two Passive Bookshelf speakers from Polk Audio and Wharfedale.
Let's have a brief look at the main features
of Polk S20 and Wharfedale EVO4.2 first before getting into our more
detailed comparison.
| Key Specs | Polk S20 | Wharfedale EVO4.2 |
|---|
| Brand | Polk Audio
United States · founded 1972 | Wharfedale
United Kingdom · founded 1932 |
|---|
| Design | 2-way | 3-way |
|---|
| Tweeter | 1" Soft-Dome | 1.18x2.36" AMT (Ribbon) |
|---|
| Midrange | — | 2" |
|---|
| Woofer | 6.5" Mica-reinforced polypropylene | 6.5" Kevlar |
|---|
| Frequency response | 39-40k Hz | 54-22k Hz |
|---|
| Sensitivity | 88 dB | 88 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 20-125 watts | 25-120 watts |
|---|
| Weight | 7.73kg / 17lbs | 13.40kg / 29.5lbs |
|---|
| Dimensions (H x W x D) | 14.8" x 8.5" x 13.7"
376.0 x 216.0 x 350.0mm | 17.9" x 9.8" x 13.7"
455.0 x 250.0 x 350.0mm |
|---|
What size room are the Polk S20 and Wharfedale EVO4.2 speakers good for?
The size of the room in which you are planning to use these loudspeakers is an important decision
factor. Here we have compared their suitability to various sizes of environments considering their size
and max power parameters:
| Listening Environment* |
Polk S20 |
Wharfedale EVO4.2 |
| Near-field |
Poor |
Poor |
| Small Room |
Average |
Average |
| Mid-size Room |
Good |
Good |
| Large Room |
Average |
Average |
| Very Large Room |
Poor |
Poor |
(* 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.)
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
Drivers
One of the fundamental differences between these two speakers is that S20 is a 2-way design whereas the EVO4.2 is a 3-way speaker. 3-way designs utilize a midrange driver in addition to the tweeter and woofer on 2-way designs. Designing a crossover for a 3-way speaker is a complicated process and generally increases the overall cost of the speaker.
Polk S20Wharfedale EVO4.2
TweeterMidrangeWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
Polk S20 |
Wharfedale EVO4.2 |
|
Driver Setup
|
2-way
|
3-way
|
|
Tweeter
|
1-inch
|
1.18x2.36-inch
|
|
Midrange
|
- |
1 x 2-inch |
|
Woofer
|
1 x 6.5-inch
|
1 x 6.5-inch
|
S20 features a 1" Terylene Soft-Dome Tweeter and 1 x 6.5" Mica-reinforced polypropylene Woofer with a Crossover frequency at 2500Hz. On the other hand, the EVO4.2 features a 1.18x2.36" AMT (Ribbon) Tweeter, a 2" Midrange and 1 x 6.5" Kevlar Woofer.
Frequency Response
S20 has a frequency range of 39-40k Hz whereas EVO4.2 has a frequency range of 54-22k Hz. With a minimum frequency of 39Hz, the S20 can go significantly deeper on the low side and provide stronger bass compared to the EVO4.2's min frequency of 54Hz.
The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the Bookshelf class in our database.
Low Frequency
Bookshelf Speakers
Neither pair reaches down to 20Hz, the usual definition of full-range, which is normal for speakers of this size. If you want the bottom octave for movies or bass-heavy music, add a subwoofer to whichever you choose. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
S20 and EVO4.2 have the same Impedance of 8 ohms and their sensitivity is also same at 88 dB.
Sensitivity
Bookshelf Speakers
Power Range
Power
range is the range of input power in watts RMS that a loudspeaker is designed to handle. Staying
within that range gives nominal performance; driving the speaker beyond its maximum wattage can damage it.
S20 can handle a max power of 125 watts RMS, whereas EVO4.2 has a max power handling value of 120 watts RMS, 5 watts less than the S20.
Note that higher power handling does not make a speaker louder: that depends mainly on
sensitivity and impedance. The calculator below shows how loud each of these actually plays
on a real amplifier.
Which plays louder on your amplifier?
Starting with a popular amplifier - change it to the one you own, or any you are
considering, and watch both numbers move.
Input Type and Bi-Amping / Bi-Wiring
EVO4.2 features Binding post posts which make bi-amping or bi-wiring possible. S20 has a 5-way post which doesn't feature bi-amping/bi-wiring.
Cabinet Type and Port Position
S20 has a rear firing port whereas EVO4.2 has a bottom firing ports. Wharfedale EVO4.2's bottom-firing port gives more flexibility in placement in regards to proximity to walls compared to Polk S20 with its rear-firing port.
Physical Specs
The size of a speaker can sometimes be an important decision factor due to space constraints or in some cases purely for esthetic reasons. In this section, we are going to compare Polk S20's and Wharfedale EVO4.2's external dimensions. Polk S20 has external dimensions of 376.0 x 216.0 x 350.0mm (14.8 x 8.5 x 13.7inch) whereas Wharfedale EVO4.2 has external dimensions of 455.0 x 250.0 x 350.0mm (17.9 x 9.8 x 13.7inch).
Below you can see the front view size comparison of Polk S20 and Wharfedale EVO4.2 in scale.
Comparison image of Polk S20 and Wharfedale EVO4.2 Size and External Dimensions
Base Surface Area Comparison
Base surface area of a loudspeaker may become a determining factor when the space in your room or desk is limited.
The base surface area of the Polk S20 is approximately 756.0cm2 / 117.2inch2 and base area of the Wharfedale EVO4.2 is approximately 875.0cm2 / 135.6inch2. The S20 requires 14% less surface area than the EVO4.2 which gives it a small advantage on placement in tight spaces.
Weight Comparison The weight of a loudspeaker can become an important factor if you need to move and reposition the unit often. Weight of a speaker can also "sometimes" be an indicator of the rigidity of the enclosure and the quality of the internal components used. The Polk S20 weighs 7.73kg / 17lbs and the Wharfedale EVO4.2 weighs 13.40kg / 29.5lbs. This makes the EVO4.2 73% heavier than the S20.
Here is a comparison of how S20 and EVO4.2's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
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
What's in the Box of Wharfedale EVO4.2?
Here are the items that come with the EVO4.2:
- 2 Bookshelf loudspeakers
- 2 Grilles
- 4 Jumper-bars (pre-installed)
- 8 Self-adhesive rubber feet
- Pair of white cloth gloves
- User Manual
 Max Input Power |
125 watts
vs
120 watts
|
Handle more power from your amplifier |
 Low Frequency Response |
39 Hz
vs
54 Hz
|
Generates deeper bass |
 High Frequency Response |
40k Hz
vs
22k Hz
|
Generates higher frequency |
 Base Surface Area |
756cm2
vs
875cm2
|
Takes less floor space |
 Price per pair* |
299USD
vs
1199USD
|
costs less (*prices may change depending on the seller, location and time) |
 Driver Setup |
3-way
vs
2-way
|
Have a dedicated mid-range driver |
 Bi-Amping and Bi-Wiring |
Yes
vs
No
|
Allows bi-amping and bi-wiring connections |
| General |
Polk Audio Signature S20 |
Wharfedale EVO4.2 |
| Brand |
Polk Audio |
Wharfedale |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
20-125 watts |
25-120 watts |
| Sensitivity |
88 dB |
88 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
n/a |
4 ohms |
| Frequency Response |
39-40k Hz |
54-22k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
6.5" |
6.5" |
| Woofer Composition |
Mica-reinforced polypropylene |
Kevlar |
| Woofer Surround Material |
Butyl rubber |
Rubber |
| Tweeter Size |
1" |
1.18x2.36" |
| Tweeter Type |
Soft-Dome |
AMT (Ribbon) |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
2" |
| Crossover Frequency |
2500Hz |
n/a |
| Firing Direction |
rear |
bottom |
Physical Specs |
|
|
| Height |
455.0mm (17.9") |
455.0mm (17.9") |
| Width |
216.0mm (8.5") |
250.0mm (9.8") |
| Depth |
350.0mm (13.8") |
350.0mm (13.8") |
| Weight |
7.73kg (17lbs) |
13.40kg (29.5lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
Meddite MDF |
MDF/Wood-veneer |
| Available Colors |
Black, Walnut, Brown Walnut |
Walnut,Black,White |
| Mounting Bracket |
No |
No |
| Recommended Stand Height |
24-28" |
18-22" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
Yes |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |
These sit in different price classes - Wharfedale EVO4.2 costs roughly 4x what Polk S20 does. Expect it to lead on paper; the question is whether the gap is audible enough in your room to be worth it.
| Area | Better | Why |
|---|
| Bass | A | Polk S20 digs deeper - 39Hz against 54Hz. |
| Amplifier needs | evenly matched | Similar sensitivity (88dB vs 88dB) - both want much the same power. |
| Headroom | evenly matched | Similar power handling (125W vs 120W). |
| Size | depends | Polk S20 is easier to place; Wharfedale EVO4.2 is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | B | Wharfedale EVO4.2: bi-amping. |
| Price | A | Polk S20 is cheaper - $299 against $1,199, about 75% less; arguably a different class. |
A Polk S20 B Wharfedale EVO4.2
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both speakers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
Neither runs away with it - they trade advantages. Let the "depends" rows and your own room settle it. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 54Hz anyway, so judge these on the other rows instead. In a large or open-plan room, Wharfedale EVO4.2 has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, Polk S20 is the easier speaker to get right.
And remember what a spec sheet cannot show: how each looks in your room and whether the finish suits it, what dealer support and warranty are like where you live, and how they actually sound to you. If you can hear them first - ideally with your own music - that will tell you more than any number above.