In this review, we will be comparing SubSeries 150 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 150 and KEF KUBE 8b first before getting into our more detailed comparison.
The sections below take each area in turn: driver and amplifier, frequency response, physical size and connectivity.
Drivers
The efficiency of a subwoofer is directly proportional to the total radiating are squared hence the woofer quantity and diameter.Both PSB SubSeries 150and KEF KUBE 8b have a single woofer setup however the PSB SubSeries 150's woofer is 6.5-inch whereas the KEF KUBE 8b features a 8-inch woofer.
Frequency Response
SubSeries 150 has a frequency range of 26-150 Hz whereas KUBE 8b has a frequency range of 34-140 Hz. With a minimum frequency of 26Hz, the SubSeries 150 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 150 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
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 SubSeries 150's and KEF KUBE 8b's external dimensions. PSB SubSeries 150 has external dimensions of 280.0 x 447.0 x 143.0mm (11 x 17-9/16 x 5-5/8inch) 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 150 is 14mm shorter and 196mm less deeper than KEF KUBE 8b but it is also 151mm wider.
Below you can see the front view size comparison of PSB SubSeries 150 and KEF KUBE 8b in scale.
Comparison image of PSB SubSeries 150 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 150 is approximately 639.2cm2 / 99.1inch2 and base area of the KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2. The SubSeries 150 requires 36% less surface area than the KUBE 8b which gives it a small advantage 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 150 weighs 6.05kg / 13.3lbs and the KEF KUBE 8b weighs 11.36kg / 25lbs. This makes the KUBE 8b 88% heavier than the SubSeries 150.
Here is a comparison of how SubSeries 150 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 150?
Here are the items that are included inside the box of SubSeries 150:
- Powered subwoofer
- 6-feet AC power cord
- 2 Mounting feet
- Wall-mount bracket
- Quick Start Subwoofer Guide
- Limited Warranty sheet
- Important Safety Instructions
What's in the Box of KEF KUBE 8b?
Here are the items that come with the KUBE 8b:
- Powered subwoofer
- 6.5-feet AC power cord
- Speaker-level input block
- User Manual
- Important Safety Information
- Warranty Information
 Low Frequency Response |
26 Hz
vs
34 Hz
|
Generates deeper bass |
 High Frequency Response |
150 Hz
vs
140 Hz
|
Generates higher frequency |
 Height |
280mm
vs
294mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
639cm2
vs
1003cm2
|
Takes less floor space |
 Price per pair* |
499USD
vs
600USD
|
costs less (*prices may change depending on the seller, location and time) |
| Woofer Size |
8 inches
vs
6.5 inches
|
Larger woofer |
Size, drawn to scale
Both subwoofers and both views share one scale, so everything here is directly comparable. Hover a box for its dimensions.
One scale for both, standing on the same floor and pushed back to the same wall, so the bigger one visibly takes more of the room.
KEF KUBE 8b needs about 57% more floor area. KEF KUBE 8b stands 196mm further into the room. KEF KUBE 8b is 14mm taller.
| General |
PSB SubSeries 150 |
KEF KUBE 8b |
| Brand |
PSB |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
100 watts |
300 watts |
| Frequency Response |
26-150 Hz |
34-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
100-watt RMS |
300-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
6.5" |
8" |
| Woofer Composition |
Polypropylene |
|
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
40-140 Hz |
| Firing Direction |
front |
front |
Physical Specs |
|
|
| Height |
280.0mm (11") |
294.0mm (11.6") |
| Width |
447.0mm (17.6") |
296.0mm (11.7") |
| Depth |
143.0mm (5.6") |
339.0mm (13.3") |
| Weight |
6.05kg (13.3lbs) |
11.36kg (25lbs) |
| Enclosure |
Acoustic Suspension |
Acoustic Suspension |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
1 Year |
2 Years |
| Labor Warranty |
1 Year |
2 Years |
No single best subwoofer here. Your room, where the box can physically go, and whether this is mainly for films or mainly for music will settle it long before the specs do.
| Area | Better | Why |
|---|
| Bass depth | A | PSB SubSeries 150 goes deeper - 26Hz against 34Hz. A real difference, though most music has little content below 34Hz. |
| Amplifier power | B | KEF KUBE 8b has the bigger amplifier - 300W against 100W RMS, about 4.8dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | B | KEF KUBE 8b moves more air: 8" against 6.5" is 1.51x the cone area, not the 1.23x the diameters suggest. More area means the same output with less excursion, and less distortion with it. |
| Enclosure | evenly matched | Both are sealed designs, so they roll off in much the same way. |
| Cabinet size | depends | PSB SubSeries 150 is about 39% smaller by volume. In a subwoofer that is a real trade rather than a preference: box volume is how you get output low down without a bigger amplifier. |
| Warranty | B | KEF KUBE 8b carries 2 years on parts against 1 years. A subwoofer amplifier works harder than anything else in the system, so this is not a throwaway line. |
| Price | A | PSB SubSeries 150 costs less - $499 against $600, about 17% less. |
A PSB SubSeries 150 B KEF KUBE 8b
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 subwoofers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
The usual trade-off: KEF KUBE 8b measures better, PSB SubSeries 150 costs about 17% less. In a normal room, placement will make a bigger difference than the gap between these two. If placement is the constraint - a corner, behind a sofa, under a desk - PSB SubSeries 150 is the one that will actually go there, and a well-placed small subwoofer beats a badly-placed big one every time.
One thing outweighs everything above: where the subwoofer stands. Room modes can add or remove 10dB or more at a given seat, which is far larger than any difference on this page. Before spending more, try the sub in two or three positions - the crawl test, where you put it in the listening seat and crawl the room to find where the bass sounds best, costs nothing and usually beats an upgrade.