In this review, we will be comparing S20 and Alpha P3, two Passive Bookshelf speakers from Polk Audio and PSB.
Let's have a brief look at the main features
of Polk S20 and PSB P3 first before getting into our more
detailed comparison.
Polk S20 Key Specs
- 2-way Design
- 1" Soft-Dome Tweeter
- 6.5" Mica-reinforced polypropylene Woofer
- 39-40k Hz Frequency Response
- 88 dB Sensitivity
- Impedance: 8ohms
- Power Range:20-125watts
- Weight:7.73kg
- Dimensions (H x W x D): 376.0" x 8.5" x 13.7"( 376.0 x 216.0 x 350.0mm )
PSB P3 Key Specs
- 2-way Design
- 0.75" Hard-Dome Tweeter
- 4.5" Polypropylene Woofer
- 57-21k Hz Frequency Response
- 87 dB Sensitivity
- Impedance: 8ohms
- Power Range:10-80watts
- Weight:2.23kg
- Dimensions (H x W x D): 223.0" x 5-3/16" x 7-5/16"( 223.0 x 132.0 x 186.0mm )
What size room are the Polk S20 and PSB P3 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 |
PSB P3 |
| Near-field |
Poor |
Average |
| Small Room |
Average |
Good |
| Mid-size Room |
Good |
Average |
| Large Room |
Average |
Poor |
| Very Large Room |
Poor |
Bad |
(* 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.)
In the following sections, we will get into more detail in order to better understand how the Polk S20 and PSB P3 compare and hopefully end up with enough arguments to decide which one of these loudspeakers is the better choice for you.
**This post contains affiliate links, and I will be compensated if you make a purchase after clicking
through my links. As an Amazon Associate I earn from qualifying purchases.
Drivers
Both S20 and Alpha P3 are 2-way speakers.
| Driver |
Polk S20 |
PSB P3 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
0.75-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 6.5-inch
|
1 x 4.5-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 Alpha P3 features a 0.75" anodized aluminum Hard-Dome Tweeter and 1 x 4.5" Polypropylene Woofer with a Crossover frequency at 3000Hz.
Frequency Response
S20 has a frequency range of 39-40k Hz whereas Alpha P3 has a frequency range of 57-21k Hz. With a minimum frequency of 39Hz, the S20 can go significantly deeper on the low side and provide stronger bass compared to the Alpha P3's min frequency of 57Hz.
Below graphs depict how these two speakers compare with the max, min and average values of the Min and Max Frequencies of other speakers in the Bookshelf class in our database.
Low Frequency
Bookshelf Speakers
High Frequency
Bookshelf Speakers
None of these speakers achieves full range experience which is commonly agreed as 20Hz-20kHz. In order to achieve lower lows / deeper bass, we recommend you pair these with a subwoofer. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
S20 and Alpha P3 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. S20 sensitivity is rated at 88 dB and the Alpha P3's is at 87 dB. This 1 dB difference makes the Polk S20 a more sensitive speaker compared to PSB P3, 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. While using
an amplifier within this range ensures the nominal performance , inputting a power that is higher than the
max wattage can result in a damaged speaker.
S20 can handle a max power of 125 watts RMS from the amp the whereas Alpha P3 has a max power handling value of 80 watts RMS, 45 watts less than the S20.
Keep in mind that a higher max power handling value doesn't necessarily make that a louder speaker
compared to a lower max handling speaker. Loudness or the sound level is also impacted by parameters
such as Impedance, sensitivity and system efficiencies.
Input Type and Bi-Amping / Bi-Wiring
S20 features 5-way post type posts and Alpha P3 has a 5-way post type posts. None of these speakers feature bi-amping/bi-wiring.
PSB P3's 5-way post terminals
Cabinet Type and Port Position
Both S20 and Alpha P3 have rear firing ports. Rear ported speakers generally need more room between the backside of the speaker and the wall compared to sealed and front/bottom ported speakers. Placing the speakers too close to the walls may cause the bass to sound boomy.
If you are limited in space and can't get the speakers away from the backwall, check our Speakers with Front Firing Ports page.
Physical Specs
Size of a speaker can sometimes become 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 PSB P3'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 PSB P3 has external dimensions of 223.0 x 132.0 x 186.0mm ( 8-3/4 x 5-3/16 x 7-5/16inch) .
Polk S20 is clearly the larger of the two speakers. Its body is 84mm wider, 153mm taller and 164mm deeper than PSB P3.
Below you can see the front view size comparison of Polk S20 and PSB P3 in scale.
Comparison image of Polk S20 and PSB P3 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 PSB P3 is approximately 245.5cm2 / 38.1inch2. The S20 requires 208% more surface area than the Alpha P3 which gives it a small disadvantage on placement in tight spaces.
Here is an 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 PSB P3 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 PSB P3 weighs 2.23kg / 4.9lbs. This makes the S20 247% heavier than the Alpha P3.
Here is a comparison of how S20 and Alpha P3'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 loudspeakers2 Grilles (attached)8 Self-adhesive rubber feetOwners ManualOnline Product Registration
What's in the Box of PSB P3?
Here are the items that come with the Alpha P3:
2 Bookshelf loudspeakers 2 Grilles 8 Self-adhesive rubber feet Quick Start Guide Warranty Card
 Max Input Power |
125 watts
vs
80 watts
|
Handle more power from your amplifier |
 Sensitivity |
88 dB
vs
87 dB
|
Play louder with same amount of amplification power |
 Woofer Size |
6.5 inches
vs
4.5 inches
|
Larger woofer |
|
Low Frequency Response |
39 Hz
vs
57 Hz
|
Generates deeper bass |
 High Frequency Response |
40k Hz
vs
21k Hz
|
Generates higher frequency |
 Height |
223mm
vs
376mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
245cm2
vs
756cm2
|
Takes less floor space |
| General |
Polk Audio Signature S20 |
PSB Alpha P3 |
| Brand |
Polk Audio |
PSB |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
20-125 watts |
10-80 watts |
| Sensitivity |
88 dB |
87 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
n/a |
4 ohms |
| Frequency Response |
39-40k Hz |
57-21k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
6.5" |
4.5" |
| Woofer Composition |
Mica-reinforced polypropylene |
Polypropylene |
| Woofer Surround Material |
Butyl rubber |
Rubber |
| Tweeter Size |
1" |
0.75" |
| Tweeter Type |
Soft-Dome |
Hard-Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2500Hz |
3000Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
376.0mm (14.8") |
223.0mm (8.8") |
| Width |
216.0mm (8.5") |
132.0mm (5.2") |
| Depth |
350.0mm (13.8") |
186.0mm (7.3") |
| Weight |
7.73kg (17lbs) |
2.23kg (4.9lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
Meddite MDF |
MDF, Wood-grain vinyl |
| Available Colors |
Black, Walnut, Brown Walnut |
Walnut,Black Ash |
| Mounting Bracket |
No |
No |
| Recommended Stand Height |
24-28" |
28-30" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
No |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |