In this review, we will be comparing PULSE SUB+ and KUBE 8b, two Powered Subwoofer speakers from Bluesound 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 Bluesound PULSE SUB+ 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.Bluesound PULSE SUB+and KEF KUBE 8b have the same driver set up: Both subwoofers have 1 x 8" drivers.
Frequency Response
PULSE SUB+ has a frequency range of 22-150 Hz whereas KUBE 8b has a frequency range of 34-140 Hz. With a minimum frequency of 22Hz, the PULSE SUB+ 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
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 Bluesound PULSE SUB+'s and KEF KUBE 8b's external dimensions. Bluesound PULSE SUB+ has external dimensions of 300 x 457 x 146 mm () 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).
KEF KUBE 8b is 161mm narrower and 6mm shorter than Bluesound PULSE SUB+ but it is also 193mm deeper.
Size, drawn to scale
Both speakers 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 surface and pushed back to the same wall, so the deeper one visibly sticks out further.
KEF KUBE 8b needs about 50% more floor or shelf area. KEF KUBE 8b is 193mm deeper, so it stands that much further out from the wall.
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 Bluesound PULSE SUB+ is approximately 667.2cm2 / 103.4inch2 and base area of the KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2. The PULSE SUB+ requires 34% 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 Bluesound PULSE SUB+ weighs 8.28kg / 18.2lbs and the KEF KUBE 8b weighs 11.36kg / 25lbs. This makes the KUBE 8b 37% heavier than the PULSE SUB+.
Here is a comparison of how PULSE SUB+ and KUBE 8b's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
 Low Frequency Response |
22 Hz
vs
34 Hz
|
Generates deeper bass |
 High Frequency Response |
150 Hz
vs
140 Hz
|
Generates higher frequency |
 App-Based Control |
BluOS Controller (iOS, Android)
vs
None
|
Control the speaker via an app |
 Base Surface Area |
667cm2
vs
1003cm2
|
Takes less floor space |
 Ethernet Connection |
Yes
vs
No
|
High quality streaming over Ethernet |
 Wireless Operation |
Yes
vs
No
|
Connect your subwoofer to your system wireless |
 Height |
294mm
vs
300mm
|
Easier to fit in smaller spaces |
 Price per pair* |
600USD
vs
1149USD
|
costs less (*prices may change depending on the seller, location and time) |
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 50% more floor area. KEF KUBE 8b stands 193mm further into the room.
| General |
Bluesound PULSE SUB+ |
KEF KUBE 8b |
| Brand |
Bluesound |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Frequency Response |
22-150 Hz |
34-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
150-watt RMS |
300-watt RMS |
| Watts Peak (Max) |
200-watt RMS |
n/a |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
8" |
8" |
| Woofer Composition |
Polypropylene |
|
| Woofer Surround Material |
Rubber |
n/a |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
40-140 Hz |
| Firing Direction |
n/a |
front |
Physical Specs |
|
|
| Height |
300.0mm (11.8") |
294.0mm (11.6") |
| Width |
457.0mm (18") |
296.0mm (11.7") |
| Depth |
146.0mm (5.7") |
339.0mm (13.3") |
| Weight |
8.28kg (18.2lbs) |
11.36kg (25lbs) |
| Enclosure |
|
Acoustic Suspension |
| Finish |
Matte |
n/a |
| Available Colors |
Black, White |
n/a |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| USB Port |
Type A (upgrade only), Type B mini (service) |
n/a |
| Ethernet Port |
Yes |
n/a |
Other |
|
|
| Parts Warranty |
|
2 Years |
| Labor Warranty |
|
2 Years |
Different price classes - Bluesound PULSE SUB+ costs roughly 1.9x what KEF KUBE 8b does. Before paying it, read the note below about two smaller subwoofers.
| Area | Better | Why |
|---|
| Bass depth | A | Bluesound PULSE SUB+ goes deeper - 22Hz against 34Hz. That gap covers the lowest notes of a five-string bass and a concert bass drum. |
| Amplifier power | B | KEF KUBE 8b has the bigger amplifier - 300W against 150W RMS, about 3dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | evenly matched | Near-identical radiating area (8" against 8"). |
| Wireless option | depends | Only Bluesound PULSE SUB+ offers a wireless link. It decides where the sub can go if you cannot run a cable, and is worth nothing if you can. |
| Cabinet size | depends | Bluesound PULSE SUB+ is about 32% 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. |
| Price | B | KEF KUBE 8b costs less - $600 against $1,149, about 48% less. |
A Bluesound PULSE SUB+ 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?
Neither runs away with it - they trade advantages. Let your room size and where the box can actually stand settle it. Two small subwoofers beat one big one in most rooms - a pair evens out the room modes in a way no single box can, whatever its specs. At $600 each, two KEF KUBE 8b cost about $1,200 against $1,149 for one of the other, which is worth a thought. If placement is the constraint - a corner, behind a sofa, under a desk - Bluesound PULSE SUB+ 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.