In this review, we will be comparing Alpha T20 and S50, two Passive Floor-standing speakers from PSB and Polk Audio.
Let's have a brief look at the main features
of PSB Alpha T20 and Polk S50 first before getting into our more
detailed comparison.
| Key Specs | PSB Alpha T20 | Polk S50 |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 0.75" Dome | 1" Dome |
|---|
| Woofer | 2 x 5.25" Polypropylene | 2 x 5.25" Mica-reinforced polypropylene |
|---|
| Frequency response | 36-21k Hz | 33-40k Hz |
|---|
| Sensitivity | 90 dB | 89 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 15-120 watts | 20-150 watts |
|---|
| Weight | 11.89kg / 26.2lbs | 14.50kg / 31.9lbs |
|---|
| Dimensions (H x W x D) | 34-3/16" x 8-5/16" x 9-13/16"
869.0 x 212.0 x 250.0mm | 37-7/16" x 10-5/16" x 11-1/16"
951.0 x 262.0 x 281.0mm |
|---|
What size room are the PSB Alpha T20 and Polk S50 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* |
PSB Alpha T20 |
Polk S50 |
| Near-field |
Bad |
Bad |
| Small Room |
Poor |
Poor |
| Mid-size Room |
Good |
Good |
| Large Room |
Good |
Good |
| 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.
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Drivers
Both Alpha T20 and S50 are 2-way speakers.
PSB Alpha T20Polk S50
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
PSB Alpha T20 |
Polk S50 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
0.75-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
2 x 5.25-inch
|
2 x 5.25-inch
|
Alpha T20 features a 0.75" anodized aluminum with front waveguide Dome Tweeter and 2 x 5.25" Polypropylene Woofer with a Crossover frequency at 2500Hz. On the other hand, the S50 features a 1" Terylene Dome Tweeter and 2 x 5.25" Mica-reinforced polypropylene Woofer with a Crossover frequency at 2500Hz.
Frequency Response
Alpha T20 has a frequency range of 36-21k Hz whereas S50 has a frequency range of 33-40k Hz. With a minimum frequency of 33Hz, the S50 can go slightly deeper then the Alpha T20's min frequency of 36Hz.
The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the Floor-standing class in our database.
Low Frequency
Floor-standing 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
Alpha T20 and S50 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. Alpha T20 sensitivity is rated at 90 dB and the S50's is at 89 dB. This 1 dB difference makes the PSB Alpha T20 a more sensitive speaker compared to Polk S50, hence will play louder with the same amount of watts.
Sensitivity
Floor-standing 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.
S50 can handle a max power of 150 watts RMS, whereas Alpha T20 has a max power handling value of 120 watts RMS, 30 watts less than the S50.
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
Both Alpha T20 and S50 features dual binding post speaker terminals for bi-amping or bi-wiring.
PSB Alpha T20's 5-Way post terminals allows Bi-amping or bi-wiring
Polk S50's 5-way post terminals allows Bi-amping or bi-wiring
Cabinet Type and Port Position
Alpha T20 has a rear firing port whereas S50 has a bottom firing ports. Polk S50's bottom-firing port gives more flexibility in placement in regards to proximity to walls compared to PSB Alpha T20 with its rear-firing port.
Polk S50 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 PSB Alpha T20's and Polk S50's external dimensions. PSB Alpha T20 has external dimensions of 869.0 x 212.0 x 250.0mm (34-3/16 x 8-5/16 x 9-13/16inch) whereas Polk S50 has external dimensions of 951.0 x 262.0 x 281.0mm (37-7/16 x 10-5/16 x 11-1/16inch).
Polk S50 is clearly the larger of the two speakers. Its body is 50mm wider, 82mm taller and 31mm deeper than PSB Alpha T20.
Below you can see the front view size comparison of PSB Alpha T20 and Polk S50 in scale.
Comparison image of PSB Alpha T20 and Polk S50 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 PSB Alpha T20 is approximately 530.0cm2 / 82.2inch2 and base area of the Polk S50 is approximately 736.2cm2 / 114.1inch2. The Alpha T20 requires 28% less surface area than the S50 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 PSB Alpha T20 weighs 11.89kg / 26.2lbs and the Polk S50 weighs 14.50kg / 31.9lbs. This makes the S50 22% heavier than the Alpha T20.
Here is a comparison of how Alpha T20 and S50's weights compare with the average, max and min weights in Passive Floor-standing class.
Weight
All Floor-standing Speakers
What's in the Box of PSB Alpha T20?
Here are the items that are included inside the box of Alpha T20:
- 2 Floorstanding loudspeakers
- 2 Grilles
- 8 Rubber feet
- 8 Spike feet
- 8 Hex-nuts
- Quick Start Guide
- Warranty Card
What's in the Box of Polk S50?
Here are the items that come with the S50:
- Floorstanding loudspeaker
- Grille (attached)
- 4 Feet (pre-installed)
- Owners Manual
- Online Product Registration
 Sensitivity |
90 dB
vs
89 dB
|
Play louder with same amount of amplification power |
 Height |
869mm
vs
951mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
530cm2
vs
736cm2
|
Takes less floor space |
 Max Input Power |
150 watts
vs
120 watts
|
Handle more power from your amplifier |
 Low Frequency Response |
33 Hz
vs
36 Hz
|
Generates deeper bass |
 High Frequency Response |
40k Hz
vs
21k Hz
|
Generates higher frequency |
| General |
PSB Alpha T20 |
Polk Audio Signature S50 |
| Brand |
PSB |
Polk Audio |
| Speaker Type |
Floor-standing speaker |
Floor-standing speaker |
| Power Range |
15-120 watts |
20-150 watts |
| Sensitivity |
90 dB |
89 dB |
| Impedance |
8 ohms |
8 ohms |
| Frequency Response |
36-21k Hz |
33-40k Hz |
Drivers |
|
|
| Woofer Quantity |
2 |
2 |
| Woofer Size |
5.25" |
5.25" |
| Woofer Composition |
Polypropylene |
Mica-reinforced polypropylene |
| Woofer Surround Material |
Rubber |
Butyl rubber |
| Tweeter Size |
0.75" |
1" |
| Tweeter Type |
Dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2500Hz |
2500Hz |
| Firing Direction |
rear |
bottom |
Physical Specs |
|
|
| Height |
869.0mm (34.2") |
951.0mm (37.4") |
| Width |
212.0mm (8.3") |
262.0mm (10.3") |
| Depth |
250.0mm (9.8") |
281.0mm (11.1") |
| Weight |
11.89kg (26.2lbs) |
14.50kg (31.9lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF, Wood-grain vinyl |
Meddite MDF |
| Available Colors |
Black |
Black |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
Yes |
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 |
B |
Polk S50 digs deeper - 33Hz against 36Hz. A subwoofer would even that out. |
| Amplifier needs |
evenly matched |
Similar sensitivity (90dB vs 89dB) - both want much the same power. |
| Headroom |
B |
Polk S50 takes more power (150W vs 120W) - more in hand in a big room. |
| Size |
depends |
PSB Alpha T20 is easier to place; Polk S50 is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability |
depends |
PSB Alpha T20: bi-amping; Polk S50: bi-amping. PSB Alpha T20 sits in a wider range (9 models), so a matched surround system is easier later. |
A PSB Alpha T20
B Polk S50
depends neither is better in the abstract - it turns on your room, placement 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 S50 has the edge on paper, though the margin is not large. The rows marked "depends" may matter more to you than the score does. In a large or open-plan room, Polk S50 has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, PSB Alpha T20 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.