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 a totally different setup: the Bluesound PULSE SUB features 2 x 6.5-inch drivers whereas the KUBE 8b features 1 x 8-inch drivers.
Frequency Response
PULSE SUB has a frequency range of whereas KUBE 8b has a frequency range of 34-140 Hz. With a minimum frequency of Hz, 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 330 x 292 x 315 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).
Bluesound PULSE SUB is 4mm narrower and 24mm less deeper than KEF KUBE 8b but it is also 36mm taller.
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 9% more floor or shelf area. KEF KUBE 8b is 24mm deeper, so it stands that much further out from the wall. Bluesound PULSE SUB is 36mm taller.
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 919.8cm2 / 142.6inch2 and base area of the KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2. The PULSE SUB requires 8% 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 10.00kg / 22lbs and the KEF KUBE 8b weighs 11.36kg / 25lbs. This makes the KUBE 8b 14% 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
 Number of Woofers |
2
vs
1
|
More woofers |
| Low Frequency Response |
Hz
vs
34 Hz
|
Generates deeper bass |
 App-Based Control |
BluOS Controller (iOS, Android, Windows, macOS)
vs
None
|
Control the speaker via an app |
 Base Surface Area |
919cm2
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 |
| Woofer Size |
8 inches
vs
6.5 inches
|
Larger woofer |
 High Frequency Response |
140 Hz
vs
Hz
|
Generates higher frequency |
 Height |
294mm
vs
330mm
|
Easier to fit in smaller spaces |
 Price per pair* |
600USD
vs
1299USD
|
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 9% more floor area. KEF KUBE 8b stands 24mm further into the room. Bluesound PULSE SUB is 36mm taller.
| General |
Bluesound PULSE SUB |
KEF KUBE 8b |
| Brand |
Bluesound |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Frequency Response |
|
34-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
350-watt RMS |
300-watt RMS |
Drivers |
|
|
| Woofer Quantity |
2 |
1 |
| Woofer Size |
6.5" |
8" |
| Woofer Composition |
|
|
| 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 |
330.0mm (13") |
294.0mm (11.6") |
| Width |
292.0mm (11.5") |
296.0mm (11.7") |
| Depth |
315.0mm (12.4") |
339.0mm (13.3") |
| Weight |
10.00kg (22lbs) |
11.36kg (25lbs) |
| Enclosure |
|
Acoustic Suspension |
| Finish |
Matte satin paint |
n/a |
| Available Colors |
Black, White/Tan |
n/a |
| Grille |
Removable magnetic |
n/a |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Ethernet Port |
Yes |
n/a |
Other |
|
|
| Parts Warranty |
|
2 Years |
| Labor Warranty |
|
2 Years |
Different price classes - Bluesound PULSE SUB costs roughly 2.2x what KEF KUBE 8b does. Before paying it, read the note below about two smaller subwoofers.
| Area | Better | Why |
|---|
| Amplifier power | evenly matched | Much the same amplifier (350W vs 300W RMS) - under 1dB apart. |
| Driver area | A | Bluesound PULSE SUB moves more air: 2 x 6.5" against 8" is 1.32x the cone area, not the 1.15x the diameters suggest. More area means the same output with less excursion, and less distortion with it. |
| 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. |
| Price | B | KEF KUBE 8b costs less - $600 against $1,299, about 54% 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?
Bluesound PULSE SUB is ahead, but on only 1 of the measured areas, and it costs about 117% more. KEF KUBE 8b is the sensible buy unless your room is large enough to need the extra. 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 $1,299 for one of the other, which is worth a thought.
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.