In this review, we will be comparing Q SUB100 and KUBE 8b, two Powered Subwoofer speakers from Q Acoustics 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 Q Acoustics Q SUB100 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 Q Acoustics Q SUB100and KEF KUBE 8b have a single woofer setup however the Q Acoustics Q SUB100's woofer is 10-inch whereas the KEF KUBE 8b features a 8-inch woofer.
Frequency Response
Q SUB100 has a frequency range of 32-250 Hz whereas KUBE 8b has a frequency range of 34-140 Hz. With a minimum frequency of 32Hz, the Q SUB100 can go slightly deeper then 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
The Q Acoustics Q SUB100 has a Infinite Baffle type cabinet. On the other hand the KEF KUBE 8b have Acoustic Suspension type enclosure. 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 Q Acoustics Q SUB100's and KEF KUBE 8b's external dimensions. Q Acoustics Q SUB100 has external dimensions of 350.0 x 350.0 x 382.0mm (13-3/4 x 13-3/4 x 15-1/16inch) 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).
Q Acoustics Q SUB100 is clearly the larger of the two speakers. Its body is 54mm wider, 56mm taller and 43mm deeper than KEF KUBE 8b.
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.
Q Acoustics Q SUB100 needs about 33% more floor or shelf area. Q Acoustics Q SUB100 is 43mm deeper, so it stands that much further out from the wall. Q Acoustics Q SUB100 is 56mm 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 Q Acoustics Q SUB100 is approximately 1337.0cm2 / 207.2inch2 and base area of the KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2. The Q SUB100 requires 33% 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 Q Acoustics Q SUB100 weighs 16.70kg / 36.7lbs and the KEF KUBE 8b weighs 11.36kg / 25lbs. This makes the Q SUB100 47% heavier than the KUBE 8b.
Here is a comparison of how Q SUB100 and KUBE 8b's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
 Woofer Size |
10 inches
vs
8 inches
|
Larger woofer |
| Low Frequency Response |
32 Hz
vs
34 Hz
|
Generates deeper bass |
 High Frequency Response |
250 Hz
vs
140 Hz
|
Generates higher frequency |
 Height |
294mm
vs
350mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1003cm2
vs
1337cm2
|
Takes less floor space |
 Price per pair* |
600USD
vs
699USD
|
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.
Q Acoustics Q SUB100 needs about 33% more floor area. Q Acoustics Q SUB100 stands 43mm further into the room. Q Acoustics Q SUB100 is 56mm taller.
| General |
Q Acoustics Q SUB100 |
KEF KUBE 8b |
| Brand |
Q Acoustics |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
250 watts |
300 watts |
| Frequency Response |
32-250 Hz |
34-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
250-watt RMS |
300-watt RMS |
| Watts Peak (Max) |
500-watt RMS |
n/a |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
10" |
8" |
| Woofer Composition |
Paper composite |
|
| 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 |
350.0mm (13.8") |
294.0mm (11.6") |
| Width |
350.0mm (13.8") |
296.0mm (11.7") |
| Depth |
382.0mm (15") |
339.0mm (13.3") |
| Weight |
16.70kg (36.7lbs) |
11.36kg (25lbs) |
| Enclosure |
Infinite Baffle |
Acoustic Suspension |
| Grille |
Yes |
n/a |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
5 Years |
2 Years |
| Labor Warranty |
5 Years |
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 | evenly matched | Effectively the same reach (32Hz vs 34Hz). |
| Amplifier power | evenly matched | Much the same amplifier (250W vs 300W RMS) - under 1dB apart. |
| Driver area | A | Q Acoustics Q SUB100 moves more air: 10" against 8" is 1.56x the cone area, not the 1.25x 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 | KEF KUBE 8b is about 37% 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 | A | Q Acoustics Q SUB100 carries 5 years on parts against 2 years. A subwoofer amplifier works harder than anything else in the system, so this is not a throwaway line. |
| Price | B | KEF KUBE 8b costs less - $600 against $699, about 14% less. |
A Q Acoustics Q SUB100 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: Q Acoustics Q SUB100 measures better, KEF KUBE 8b costs about 14% 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 - KEF KUBE 8b 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.