In this review, we will be comparing SubSeries 250 and KUBE 8b, two Powered Subwoofer speakers from PSB and KEF. Being Powered subwoofers, they both have built-in amplifiers so you don't need an external power amp or an integrated amp to power them. Let's have a brief look at the main features of PSB SubSeries 250 and KEF KUBE 8b first before getting into our more detailed comparison.
In the following sections, we will get into details in order to better understand how the PSB SubSeries 250 and KEF KUBE 8b compare and hopefully end up with enough arguments to decide which one of these subwoofers 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
The efficiency of a subwoofer is directly proportional to the total radiating are squared hence the woofer quantity and diameter.Both PSB SubSeries 250and KEF KUBE 8b have a single woofer setup however the PSB SubSeries 250's woofer is 10-inch whereas the KEF KUBE 8b features a 8-inch woofer.
Frequency Response
SubSeries 250 has a frequency range of 25-150 Hz whereas KUBE 8b has a frequency range of 34-140 Hz. With a minimum frequency of 25Hz, the SubSeries 250 can go significantly deeper on the low side and provide stronger bass compared to the KUBE 8b's min frequency of 34Hz.
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 Subwoofer class in our database.
Low Frequency
Subwoofer Speakers
High Frequency
Subwoofer Speakers
Cabinet Type
Both PSB SubSeries 250 and KEF KUBE 8b have Acoustic Suspension type cabinets. Acoustic Suspension aka Sealed type subwoofers have enclosures that are sealed hence no ports or holes exists on the cabinet. Sealed designs helps to provide more accurate and tight bass responses compared to ported designs.
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 PSB SubSeries 250's and KEF KUBE 8b's external dimensions. PSB SubSeries 250 has external dimensions of 362.0 x 348.0 x 397.0mm ( 14-1/4 x 13-11/16 x 15-5/8inch) whereas KEF KUBE 8b has external dimensions of 294.0 x 296.0 x 339.0mm ( 11-9/16 x 11-5/8 x 13-5/16inch) .
PSB SubSeries 250 is clearly the larger of the two speakers. Its body is 52mm wider, 68mm taller and 58mm deeper than KEF KUBE 8b.
Below you can see the front view size comparison of PSB SubSeries 250 and KEF KUBE 8b in scale.
Comparison image of PSB SubSeries 250 and KEF KUBE 8b 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 SubSeries 250 is approximately 1381.6cm2 / 214.1inch2 and base area of the KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2. The SubSeries 250 requires 38% more surface area than the KUBE 8b which gives it a small disadvantage on placement in tight spaces.
Weight Comparison The weight of a subwoofer may become an important factor if you need to move and reposition the unit often to find the optimal positioning, also known as 'Subwoofer Crawling'. The PSB SubSeries 250 weighs 19.09kg / 42lbs and the KEF KUBE 8b weighs 11.36kg / 25lbs. This makes the SubSeries 250 68% heavier than the KUBE 8b.
Here is a comparison of how SubSeries 250 and KUBE 8b's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
What's in the Box of PSB SubSeries 250?
Here are the items that are included inside the box of SubSeries 250:
Powered subwooferGrille6-feet AC power cordQuick Start GuideImportant Safety InstructionsWarranty Information
What's in the Box of KEF KUBE 8b?
Here are the items that come with the KUBE 8b:
Powered subwoofer6.5-feet AC power cordSpeaker-level input blockUser ManualImportant Safety InformationWarranty Information
 Woofer Size |
10 inches
vs
8 inches
|
Larger woofer |
| Low Frequency Response |
25 Hz
vs
34 Hz
|
Generates deeper bass |
 High Frequency Response |
150k Hz
vs
140k Hz
|
Generates higher frequency |
 Wireless Operation |
Optional
vs
No
|
Connect your subwoofer to your system wireless |
 Height |
294mm
vs
362mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1003cm2 (296x339mm)
vs
1381cm2 (348x397mm)
|
Takes less floor space |
 Price per pair* |
600USD
vs
999USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
PSB SubSeries 250 |
KEF KUBE 8b |
| Brand |
PSB |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
200 watts |
300 watts |
| Frequency Response |
25-150 Hz |
34-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
200-watt RMS |
300-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
10" |
8" |
| Woofer Composition |
Polypropylene |
Not given |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
50-150 Hz and 80 Hz |
40-140 Hz |
| Firing Direction |
front |
front |
Physical Specs |
|
|
| Height |
362.0mm (14.3") |
294.0mm (11.6") |
| Width |
348.0mm (13.7") |
296.0mm (11.7") |
| Depth |
397.0mm (15.6") |
339.0mm (13.3") |
| Weight |
19.09kg (42lbs) |
11.36kg (25lbs) |
| Enclosure |
Acoustic Suspension |
Acoustic Suspension |
| Grille |
Yes |
n/a |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
1 Year |
2 Years |
| Labor Warranty |
1 Year |
2 Years |