In this review, we will be comparing Concerta B8 and KUBE 8b, two Powered Subwoofer speakers from Revel 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 Revel Concerta B8 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.Revel Concerta B8and KEF KUBE 8b have the same driver set up: Both subwoofers have 1 x 8" drivers.
Frequency Response
Concerta B8 has a frequency range of 45-200 Hz whereas KUBE 8b has a frequency range of 34-140 Hz. With a minimum frequency of 34Hz, the KUBE 8b can go significantly deeper on the low side and provide stronger bass compared to the Concerta B8's min frequency of 45Hz.
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
Both Revel Concerta B8 and KEF KUBE 8b have Acoustic Suspension type cabinets. 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 Revel Concerta B8's and KEF KUBE 8b's external dimensions. Revel Concerta B8 has external dimensions of 355.0 x 269.0 x 288.0mm (13-15/16 x 10-9/16 x 11-5/16inch) 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).
Revel Concerta B8 is 27mm narrower and 51mm less deeper than KEF KUBE 8b but it is also 61mm taller.
Below you can see the front view size comparison of Revel Concerta B8 and KEF KUBE 8b in scale.
Comparison image of Revel Concerta B8 and KEF KUBE 8b 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 Revel Concerta B8 is approximately 774.7cm2 / 120.1inch2 and base area of the KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2. The Concerta B8 requires 23% 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 Revel Concerta B8 weighs 9.00kg / 19.8lbs and the KEF KUBE 8b weighs 11.36kg / 25lbs. This makes the KUBE 8b 26% heavier than the Concerta B8.
Here is a comparison of how Concerta B8 and KUBE 8b's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
What's in the Box of Revel Concerta B8?
Here are the items that are included inside the box of Concerta B8:
- Wireless powered subwoofer
- Wireless transmitter
- AC power adapter (attached 6-feet DC cord)
- 6-feet AC power cord
- 16-feet Subwoofer/Trigger cable (male RCA and male minijack connector on each end) Owners Manual
- Important Safety Instructions
What's in the Box of KEF KUBE 8b?
Here are the items that come with the KUBE 8b:
- Powered subwoofer
- 6.5-feet AC power cord
- Speaker-level input block
- User Manual
- Important Safety Information
- Warranty Information
 High Frequency Response |
200 Hz
vs
140 Hz
|
Generates higher frequency |
 Base Surface Area |
774cm2
vs
1003cm2
|
Takes less floor space |
 Price per pair* |
499USD
vs
600USD
|
costs less (*prices may change depending on the seller, location and time) |
 Wireless Operation |
Yes
vs
No
|
Connect your subwoofer to your system wireless |
 Low Frequency Response |
34 Hz
vs
45 Hz
|
Generates deeper bass |
 Height |
294mm
vs
355mm
|
Easier to fit in smaller spaces |
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 30% more floor area. KEF KUBE 8b stands 51mm further into the room. Revel Concerta B8 is 61mm taller.
| General |
Revel Concerta B8 |
KEF KUBE 8b |
| Brand |
Revel |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
200 watts |
300 watts |
| Frequency Response |
45-200 Hz |
34-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
200-watt RMS |
300-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
8" |
8" |
| Woofer Composition |
Paper |
|
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
40-140 Hz |
| Firing Direction |
bottom |
front |
Physical Specs |
|
|
| Height |
355.0mm (14") |
294.0mm (11.6") |
| Width |
269.0mm (10.6") |
296.0mm (11.7") |
| Depth |
288.0mm (11.3") |
339.0mm (13.3") |
| Weight |
9.00kg (19.8lbs) |
11.36kg (25lbs) |
| Enclosure |
Acoustic Suspension |
Acoustic Suspension |
| 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 | B | KEF KUBE 8b goes deeper - 34Hz against 45Hz. A real difference, though most music has little content below 45Hz. |
| Amplifier power | B | KEF KUBE 8b has the bigger amplifier - 300W against 200W RMS, about 1.8dB 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 | evenly matched | Both are sealed designs, so they roll off in much the same way. |
| Wireless option | depends | Only Revel Concerta B8 offers a wireless link. It decides where the sub can go if you cannot run a cable, and is worth nothing if you can. |
| Driver placement | depends | Revel Concerta B8 fires down and KEF KUBE 8b fires front. A down-firing driver is more forgiving of a grille-less look and of a hard floor; a front-firing one is the safer choice on a thick carpet or a suspended timber floor. |
| Warranty | A | Revel Concerta B8 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 | A | Revel Concerta B8 costs less - $499 against $600, about 17% less. |
A Revel Concerta B8 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: KEF KUBE 8b measures better, Revel Concerta B8 costs about 17% less. In a normal room, placement will make a bigger difference than the gap between these two.
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.