In this review, we will be comparing Diamond 12.3 and Alpha T20, two Passive Floor-standing speakers from Wharfedale and PSB.
Let's have a brief look at the main features
of Wharfedale Diamond 12.3 and PSB Alpha T20 first before getting into our more
detailed comparison.
| Key Specs | Wharfedale Diamond 12.3 | PSB Alpha T20 |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 1" Soft-Dome | 0.75" Dome |
|---|
| Woofer | 2 x 5" Mica-infused polypropylene | 2 x 5.25" Polypropylene |
|---|
| Frequency response | 45-20k Hz | 36-21k Hz |
|---|
| Sensitivity | 88 dB | 90 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 30-150 watts | 15-120 watts |
|---|
| Weight | 19.50kg / 42.9lbs | 11.89kg / 26.2lbs |
|---|
| Dimensions (H x W x D) | 38-3/4" x 7-1/8" x 14-1/4"
985.0 x 180.0 x 362.0mm | 34-3/16" x 8-5/16" x 9-13/16"
869.0 x 212.0 x 250.0mm |
|---|
What size room are the Wharfedale Diamond 12.3 and PSB Alpha T20 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* |
Wharfedale Diamond 12.3 |
PSB Alpha T20 |
| 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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through our links. As an Amazon Associate I earn from qualifying purchases.
Drivers
Both Diamond 12.3 and Alpha T20 are 2-way speakers.
Wharfedale Diamond 12.3PSB Alpha T20
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
Wharfedale Diamond 12.3 |
PSB Alpha T20 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
0.75-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
2 x 5-inch
|
2 x 5.25-inch
|
Diamond 12.3 features a 1" Textile Soft-Dome Tweeter and 2 x 5" Mica-infused polypropylene Woofer with a Crossover frequency at 2200Hz. On the other hand, the 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.
Frequency Response
Diamond 12.3 has a frequency range of 45-20k Hz whereas Alpha T20 has a frequency range of 36-21k Hz. With a minimum frequency of 36Hz, the Alpha T20 can go significantly deeper on the low side and provide stronger bass compared to the Diamond 12.3'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 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
Diamond 12.3 and Alpha T20 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. Diamond 12.3 sensitivity is rated at 88 dB and the Alpha T20's is at 90 dB. This 2 dB difference makes the PSB Alpha T20 a more sensitive speaker compared to Wharfedale Diamond 12.3, 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.
Diamond 12.3 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 Diamond 12.3.
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 Diamond 12.3 and Alpha T20 features dual binding post speaker terminals for bi-amping or bi-wiring.
Wharfedale Diamond 12.3's Binding post terminals allows Bi-amping or bi-wiring
PSB Alpha T20's 5-Way post terminals allows Bi-amping or bi-wiring
Cabinet Type and Port Position
Both Diamond 12.3 and Alpha T20 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
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 Wharfedale Diamond 12.3's and PSB Alpha T20's external dimensions. Wharfedale Diamond 12.3 has external dimensions of 985.0 x 180.0 x 362.0mm (38-3/4 x 7-1/8 x 14-1/4inch) whereas 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).
PSB Alpha T20 is 116mm shorter and 112mm less deeper than Wharfedale Diamond 12.3 but it is also 32mm wider.
Below you can see the front view size comparison of Wharfedale Diamond 12.3 and PSB Alpha T20 in scale.
Comparison image of Wharfedale Diamond 12.3 and PSB Alpha T20 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 Wharfedale Diamond 12.3 is approximately 651.6cm2 / 101.0inch2 and base area of the PSB Alpha T20 is approximately 530.0cm2 / 82.2inch2. The Diamond 12.3 requires 23% more surface area than the Alpha T20 which gives it a small disadvantage 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 Wharfedale Diamond 12.3 weighs 19.50kg / 42.9lbs and the PSB Alpha T20 weighs 11.89kg / 26.2lbs. This makes the Diamond 12.3 64% heavier than the Alpha T20.
Here is a comparison of how Diamond 12.3 and Alpha T20'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 Wharfedale Diamond 12.3?
Here are the items that are included inside the box of Diamond 12.3:
- Floorstanding loudspeaker
- Grille
- 4 Spike feet (w/ locking collars)
- 2 Jumper-bars (pre-installed)
- 4 Isolation pucks
- Users Manual
What's in the Box of PSB Alpha T20?
Here are the items that come with the Alpha T20:
- 2 Floorstanding loudspeakers
- 2 Grilles
- 8 Rubber feet
- 8 Spike feet
- 8 Hex-nuts
- Quick Start Guide
- Warranty Card
 Max Input Power |
150 watts
vs
120 watts
|
Handle more power from your amplifier |
 Sensitivity |
90 dB
vs
88 dB
|
Play louder with same amount of amplification power |
 Woofer Size |
5.25 inches
vs
5 inches
|
Larger woofer |
|
Low Frequency Response |
36 Hz
vs
45 Hz
|
Generates deeper bass |
 High Frequency Response |
21k Hz
vs
20k Hz
|
Generates higher frequency |
 Height |
869mm
vs
985mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
530cm2
vs
651cm2
|
Takes less floor space |
 Price per pair* |
799USD
vs
998USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Wharfedale Diamond 12.3 |
PSB Alpha T20 |
| Brand |
Wharfedale |
PSB |
| Speaker Type |
Floor-standing speaker |
Floor-standing speaker |
| Power Range |
30-150 watts |
15-120 watts |
| Sensitivity |
88 dB |
90 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
5 ohms |
n/a |
| Frequency Response |
45-20k Hz |
36-21k Hz |
Drivers |
|
|
| Woofer Quantity |
2 |
2 |
| Woofer Size |
5" |
5.25" |
| Woofer Composition |
Mica-infused polypropylene |
Polypropylene |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
0.75" |
| Tweeter Type |
Soft-Dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2200Hz |
2500Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
985.0mm (38.8") |
869.0mm (34.2") |
| Width |
180.0mm (7.1") |
212.0mm (8.3") |
| Depth |
362.0mm (14.3") |
250.0mm (9.8") |
| Weight |
19.50kg (42.9lbs) |
11.89kg (26.2lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF/Wood-grain vinyl |
MDF, Wood-grain vinyl |
| Available Colors |
Black, Oak, Walnut |
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 |
PSB Alpha T20 digs deeper - 36Hz against 45Hz. A subwoofer would even that out. |
| Amplifier needs |
B |
PSB Alpha T20 is more sensitive (90dB vs 88dB), so it goes louder on the same amplifier. |
| Headroom |
A |
Wharfedale Diamond 12.3 takes more power (150W vs 120W) - more in hand in a big room. |
| Size |
depends |
PSB Alpha T20 is easier to place; Wharfedale Diamond 12.3 is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability |
depends |
Wharfedale Diamond 12.3: bi-amping; PSB Alpha T20: bi-amping. Wharfedale Diamond 12.3 sits in a wider range (12 models), so a matched surround system is easier later. |
| Price |
B |
PSB Alpha T20 is cheaper - $799 against $998, about 20% less. |
A Wharfedale Diamond 12.3
B PSB Alpha T20
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?
PSB Alpha T20 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. If your amplifier is modest, vintage or valve-based, PSB Alpha T20 is the safer partner - the other will want more current or more watts to sound its best.
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.