In this review, we will be comparing TZero MKIII and KUBE 10b, two Powered Subwoofer speakers from REL 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 REL TZero MKIII and KEF KUBE 10b 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 REL TZero MKIIIand KEF KUBE 10b have a single woofer setup however the REL TZero MKIII's woofer is 6.5-inch whereas the KEF KUBE 10b features a 10-inch woofer.
Frequency Response
TZero MKIII has a frequency range of 37-120 Hz whereas KUBE 10b has a frequency range of 24-140 Hz. With a minimum frequency of 24Hz, the KUBE 10b can go significantly deeper on the low side and provide stronger bass compared to the TZero MKIII's min frequency of 37Hz.
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 REL TZero MKIII's and KEF KUBE 10b's external dimensions. REL TZero MKIII has external dimensions of 242.9 x 217.5 x 295.3mm () whereas KEF KUBE 10b has external dimensions of 372.0 x 356.0 x 397.0mm (14-5/8 x 14 x 15-5/8inch).
KEF KUBE 10b is clearly the larger of the two speakers. Its body is 138.5mm wider, 129.1mm taller and 101.7mm deeper than REL TZero MKIII.
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 REL TZero MKIII is approximately 642.3cm2 / 99.6inch2 and base area of the KEF KUBE 10b is approximately 1413.3cm2 / 219.1inch2. The TZero MKIII requires 55% less surface area than the KUBE 10b 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 REL TZero MKIII weighs 6.80kg / 15lbs and the KEF KUBE 10b weighs 17.50kg / 38.5lbs. This makes the KUBE 10b 157% heavier than the TZero MKIII.
Here is a comparison of how TZero MKIII and KUBE 10b's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
 Height |
242mm
vs
372mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
642cm2
vs
1413cm2
|
Takes less floor space |
 Price per pair* |
599USD
vs
750USD
|
costs less (*prices may change depending on the seller, location and time) |
 Woofer Size |
10 inches
vs
6.5 inches
|
Larger woofer |
| Low Frequency Response |
24 Hz
vs
37 Hz
|
Generates deeper bass |
 High Frequency Response |
140 Hz
vs
120 Hz
|
Generates higher frequency |
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 10b needs about 120% more floor area. KEF KUBE 10b stands 102mm further into the room. KEF KUBE 10b is 129mm taller.
| General |
REL TZero MKIII |
KEF KUBE 10b |
| Brand |
REL |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Frequency Response |
37-120 Hz |
24-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
100-watt RMS |
300-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
6.5" |
10" |
| 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 |
242.9mm (9.6") |
372.0mm (14.6") |
| Width |
217.5mm (8.6") |
356.0mm (14") |
| Depth |
295.3mm (11.6") |
397.0mm (15.6") |
| Weight |
6.80kg (15lbs) |
17.50kg (38.5lbs) |
| Enclosure |
|
Acoustic Suspension |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
3 Years |
2 Years |
| Labor Warranty |
3 Years |
2 Years |
Two quite different sizes of subwoofer. Room volume decides this more than anything else on the page: a big driver in a small room is wasted, and a small one in a large room is worked to death.
| Area | Better | Why |
|---|
| Bass depth | B | KEF KUBE 10b goes deeper - 24Hz against 37Hz. That gap covers the lowest notes of a five-string bass and a concert bass drum. |
| Amplifier power | B | KEF KUBE 10b 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 10b moves more air: 10" against 6.5" is 2.37x the cone area, not the 1.54x 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 | REL TZero MKIII is about 70% 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 | REL TZero MKIII carries 3 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 | A | REL TZero MKIII costs less - $599 against $750, about 20% less. |
A REL TZero MKIII B KEF KUBE 10b
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 10b measures better, REL TZero MKIII costs about 20% 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 - REL TZero MKIII 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.