In this review, we will be comparing KUBE 8b and SuperCube 4000, two Powered Subwoofer speakers from KEF and Definitive Technology. 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 KEF KUBE 8b and DT SuperCube 4000 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.KEF KUBE 8band DT SuperCube 4000 have the same driver set up: Both subwoofers have 1 x 8" drivers.
Frequency Response
KUBE 8b has a frequency range of 34-140 Hz whereas SuperCube 4000 has a frequency range of 16-200 Hz. With a minimum frequency of 16Hz, the SuperCube 4000 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
The KEF KUBE 8b has a Acoustic Suspension type cabinet. 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. On the other hand the DT SuperCube 4000 have Passive Radiator type enclosure. Passive Radiator type subwoofers sports a non-powered cone that moves in response to the main woofer to move air out in order to generate stronger bass in a smaller body compared to ported or sealed 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 KEF KUBE 8b's and DT SuperCube 4000's external dimensions. 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) whereas DT SuperCube 4000 has external dimensions of 302.0 x 281.0 x 318.0mm (11-7/8 x 11-1/16 x 12-1/2inch).
DT SuperCube 4000 is 15mm narrower and 21mm less deeper than KEF KUBE 8b but it is also 8mm taller.
Below you can see the front view size comparison of KEF KUBE 8b and DT SuperCube 4000 in scale.
Comparison image of KEF KUBE 8b and DT SuperCube 4000 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 KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2 and base area of the DT SuperCube 4000 is approximately 893.6cm2 / 138.5inch2. The KUBE 8b requires 12% more surface area than the SuperCube 4000 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 KEF KUBE 8b weighs 11.36kg / 25lbs and the DT SuperCube 4000 weighs 11.36kg / 25lbs.
Here is a comparison of how KUBE 8b and SuperCube 4000's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
What's in the Box of KEF KUBE 8b?
Here are the items that are included inside the box of KUBE 8b:
- Powered subwoofer
- 6.5-feet AC power cord
- Speaker-level input block
- User Manual
- Important Safety Information
- Warranty Information
What's in the Box of DT SuperCube 4000?
Here are the items that come with the SuperCube 4000:
- 8-inch Powered subwoofer
- 7-feet AC power cord
- Remote control (CR2025 battery installed)
- 4 Threaded rubber-feet
- 4 Spike feet (hex-nut attached)
- Owners Manual
- SC4000 Booklet
 Height |
294mm
vs
302mm
|
Easier to fit in smaller spaces |
 Price per pair* |
600USD
vs
799USD
|
costs less (*prices may change depending on the seller, location and time) |
 Low Frequency Response |
16 Hz
vs
34 Hz
|
Generates deeper bass |
 High Frequency Response |
200 Hz
vs
140 Hz
|
Generates higher frequency |
 Base Surface Area |
893cm2
vs
1003cm2
|
Takes less floor space |
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 12% more floor area. KEF KUBE 8b stands 21mm further into the room.
| General |
KEF KUBE 8b |
Definitive Technology SuperCube 4000 |
| Brand |
KEF |
Definitive Technology |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
300 watts |
1200 watts |
| Frequency Response |
34-140 Hz |
16-200 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
300-watt RMS |
1200-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
8" |
8" |
| Woofer Composition |
|
|
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
40-140 Hz |
40-150 Hz and 40-150 Hz |
| Firing Direction |
front |
front |
Physical Specs |
|
|
| Height |
294.0mm (11.6") |
302.0mm (11.9") |
| Width |
296.0mm (11.7") |
281.0mm (11.1") |
| Depth |
339.0mm (13.3") |
318.0mm (12.5") |
| Weight |
11.36kg (25lbs) |
11.36kg (25lbs) |
| Enclosure |
Acoustic Suspension |
Passive Radiator |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
2 Years |
3 Years |
| Labor Warranty |
2 Years |
3 Years |
A sealed subwoofer against a passive radiator one. That is the most consequential line on this page: it decides how the bass rolls off, how it behaves in a small room, and how much output you get for the size of the box.
| Area | Better | Why |
|---|
| Bass depth | B | DT SuperCube 4000 goes deeper - 16Hz against 34Hz. Under 20Hz is felt more than heard - the bottom of a pipe organ and the bottom of a film mix. |
| Amplifier power | B | DT SuperCube 4000 has the bigger amplifier - 1200W against 300W RMS, about 6dB 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"). |
| Enclosure | depends | KEF KUBE 8b is sealed - a sealed box rolls off gently and is usually the easier one to integrate in a small or awkward room; DT SuperCube 4000 is passive radiator - a passive radiator behaves like a port without the pipe noise, and suits a slim cabinet. Neither is better in the abstract; ported tends to suit films and sealed tends to suit music, and both generalisations have exceptions. |
| Speaker-level inputs | B | DT SuperCube 4000 takes a speaker-level connection as well as line level. That is what lets it work with an integrated amplifier or a vintage receiver that has no subwoofer output at all. |
| Warranty | B | DT SuperCube 4000 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 | KEF KUBE 8b costs less - $600 against $799, about 25% less. |
A KEF KUBE 8b B DT SuperCube 4000
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?
DT SuperCube 4000 leads across most of the measured areas for a modest premium, so it is the easier pick if the budget stretches. KEF KUBE 8b is the one to take if it does not. Films or music? If this is mainly a home cinema, DT SuperCube 4000 will hit harder for the money; if it is mainly for music in a normal-sized room, KEF KUBE 8b is usually the easier one to make sound right. Check your amplifier first: if it has no subwoofer or preamp output, DT SuperCube 4000 is the only one of these two you can connect at all.
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.