In this review, we will be comparing S20 and Diamond 225, two Passive Bookshelf speakers from Polk Audio and Wharfedale.
Let's have a brief look at the main features
of Polk S20 and Wharfedale 225 first before getting into our more
detailed comparison.
| Key Specs | Polk S20 | Wharfedale 225 |
|---|
| Brand | Polk Audio
United States · founded 1972 | Wharfedale
United Kingdom · founded 1932 |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 1" Soft-Dome | 1" Dome |
|---|
| Woofer | 6.5" Mica-reinforced polypropylene | 6.5" Woven Kevlar |
|---|
| Frequency response | 39-40k Hz | 45-20k Hz |
|---|
| Sensitivity | 88 dB | 87 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 20-125 watts | 25-120 watts |
|---|
| Weight | 7.73kg / 17lbs | 6.55kg / 14.4lbs |
|---|
| Dimensions (H x W x D) | 14.8" x 8.5" x 13.7"
376.0 x 216.0 x 350.0mm | 13.9" x 7.7" x 11.4"
355.0 x 196.0 x 290.0mm |
|---|
What size room are the Polk S20 and Wharfedale 225 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 225 |
| 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
Both S20 and Diamond 225 are 2-way speakers.
Polk S20Wharfedale 225
TweeterWoofer
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 225 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
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 Diamond 225 features a 1" Dome Tweeter and 1 x 6.5" Woven Kevlar Woofer with a Crossover frequency at 2300Hz.
Frequency Response
S20 has a frequency range of 39-40k Hz whereas Diamond 225 has a frequency range of 45-20k Hz. With a minimum frequency of 39Hz, the S20 can go significantly deeper on the low side and provide stronger bass compared to the Diamond 225's min frequency of 45Hz.
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 Diamond 225 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. S20 sensitivity is rated at 88 dB and the Diamond 225's is at 87 dB. This 1 dB difference makes the Polk S20 a more sensitive speaker compared to Wharfedale 225, hence will play louder with the same amount of watts.
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 Diamond 225 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
Diamond 225 features Post posts which make bi-amping or bi-wiring possible. S20 has a 5-way post which doesn't feature bi-amping/bi-wiring.
Wharfedale 225's Post terminals allows Bi-amping or bi-wiring
Cabinet Type and Port Position
S20 has a rear firing port whereas Diamond 225 has a bottom firing ports. Wharfedale 225'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 225'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 225 has external dimensions of 355.0 x 196.0 x 290.0mm (13.9 x 7.7 x 11.4inch).
Polk S20 is clearly the larger of the two speakers. Its body is 20mm wider, 21mm taller and 60mm deeper than Wharfedale 225.
Below you can see the front view size comparison of Polk S20 and Wharfedale 225 in scale.
Comparison image of Polk S20 and Wharfedale 225 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 225 is approximately 568.4cm2 / 88.1inch2. The S20 requires 33% more surface area than the Diamond 225 which gives it a small disadvantage on placement in tight spaces.
Here is another comparison that shows both speakers on a BDI Octave Media Cabinet, next to a standard size amplifier and turntable in scale:
Size Comparison image of Polk S20 and Wharfedale 225 on a Media Console
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 225 weighs 6.55kg / 14.4lbs. This makes the S20 18% heavier than the Diamond 225.
Here is a comparison of how S20 and Diamond 225'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 225?
Here are the items that come with the Diamond 225:
- 2 Bookshelf loudspeakers
- 2 Grilles (pre-installed)
- 8 Self-adhesive rubber feet
- User's Manual
- Installation Guide
 Max Input Power |
125 watts
vs
120 watts
|
Handle more power from your amplifier |
 Sensitivity |
88 dB
vs
87 dB
|
Play louder with same amount of amplification power |
 Low Frequency Response |
39 Hz
vs
45 Hz
|
Generates deeper bass |
 High Frequency Response |
40k Hz
vs
20k Hz
|
Generates higher frequency |
 Price per pair* |
299USD
vs
349USD
|
costs less (*prices may change depending on the seller, location and time) |
 Bi-Amping and Bi-Wiring |
Yes
vs
No
|
Allows bi-amping and bi-wiring connections |
 Height |
355mm
vs
376mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
568cm2
vs
756cm2
|
Takes less floor space |
| General |
Polk Audio Signature S20 |
Wharfedale Diamond 225 |
| Brand |
Polk Audio |
Wharfedale |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
20-125 watts |
25-120 watts |
| Sensitivity |
88 dB |
87 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
n/a |
4.2 ohms |
| Frequency Response |
39-40k Hz |
45-20k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
6.5" |
6.5" |
| Woofer Composition |
Mica-reinforced polypropylene |
Woven Kevlar |
| Woofer Surround Material |
Butyl rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Soft-Dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2500Hz |
2300Hz |
| Firing Direction |
rear |
bottom |
Physical Specs |
|
|
| Height |
376.0mm (14.8") |
355.0mm (14") |
| Width |
216.0mm (8.5") |
196.0mm (7.7") |
| Depth |
350.0mm (13.8") |
290.0mm (11.4") |
| Weight |
7.73kg (17lbs) |
6.55kg (14.4lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
Meddite MDF |
MDF/Wood veneer |
| Available Colors |
Black, Walnut, Brown Walnut |
Black, White, Walnut |
| Mounting Bracket |
No |
No |
| Recommended Stand Height |
24-28" |
24" |
| 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 |
No single best speaker here - they are built to different priorities, and the right one depends on your room, your amplifier and what you listen to.
| Area | Better | Why |
|---|
| Bass | A | Polk S20 digs deeper - 39Hz against 45Hz. A subwoofer would even that out. |
| Amplifier needs | evenly matched | Similar sensitivity (88dB vs 87dB) - both want much the same power. |
| Headroom | evenly matched | Similar power handling (125W vs 120W). |
| Size | depends | Wharfedale 225 is easier to place; Polk S20 is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | depends | Wharfedale 225: bi-amping. Polk S20 sits in a wider range (6 models), so a matched surround system is easier later. |
| Price | A | Polk S20 is cheaper - $299 against $349, about 14% less. |
A Polk S20 B Wharfedale 225
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?
Polk S20 has the edge on paper, though the margin is not large. The rows marked "depends" may matter more to you than the score does. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 45Hz anyway, so judge these on the other rows instead. In a large or open-plan room, Polk S20 has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, Wharfedale 225 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.