In this review, we will be comparing Classic 99 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 Classic 99 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 Classic 99and KEF KUBE 10b have a single woofer setup however the REL Classic 99's woofer is 12-inch whereas the KEF KUBE 10b features a 10-inch woofer.
Frequency Response
Classic 99 has a frequency range of 24-120 Hz whereas KUBE 10b has a frequency range of 24-140 Hz.
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 Classic 99's and KEF KUBE 10b's external dimensions. REL Classic 99 has external dimensions of 536.6 x 400.1 x 396.9mm () 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 44.1mm narrower and 164.6mm shorter than REL Classic 99 but it is also 0.10000000000002mm deeper.
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 Classic 99 is approximately 1588.0cm2 / 246.1inch2 and base area of the KEF KUBE 10b is approximately 1413.3cm2 / 219.1inch2. The Classic 99 requires 12% more surface area than the KUBE 10b 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 REL Classic 99 weighs 22.36kg / 49.2lbs and the KEF KUBE 10b weighs 17.50kg / 38.5lbs. This makes the Classic 99 28% heavier than the KUBE 10b.
Here is a comparison of how Classic 99 and KUBE 10b's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
 Woofer Size |
12 inches
vs
10 inches
|
Larger woofer |
 High Frequency Response |
140 Hz
vs
120 Hz
|
Generates higher frequency |
 Height |
372mm
vs
536mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1413cm2
vs
1588cm2
|
Takes less floor space |
 Price per pair* |
750USD
vs
2099USD
|
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.
REL Classic 99 needs about 12% more floor area. REL Classic 99 is 165mm taller.
| General |
REL Classic 99 |
KEF KUBE 10b |
| Brand |
REL |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Frequency Response |
24-120 Hz |
24-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
450-watt RMS |
300-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
12" |
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 |
536.6mm (21.1") |
372.0mm (14.6") |
| Width |
400.1mm (15.8") |
356.0mm (14") |
| Depth |
396.9mm (15.6") |
397.0mm (15.6") |
| Weight |
22.36kg (49.2lbs) |
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 |
Different price classes - REL Classic 99 costs roughly 2.8x what KEF KUBE 10b does. Before paying it, read the note below about two smaller subwoofers.
| Area | Better | Why |
|---|
| Bass depth | evenly matched | Effectively the same reach (24Hz vs 24Hz). |
| Amplifier power | A | REL Classic 99 has the bigger amplifier - 450W against 300W RMS, about 1.8dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | A | REL Classic 99 moves more air: 12" against 10" is 1.44x the cone area, not the 1.2x 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 10b is about 38% 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 Classic 99 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 | B | KEF KUBE 10b costs less - $750 against $2,099, about 64% less. |
A REL Classic 99 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: REL Classic 99 measures better, KEF KUBE 10b costs about 64% less. In a normal room, placement will make a bigger difference than the gap between these two. 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 $750 each, two KEF KUBE 10b cost about $1,500 against $2,099 for one of the other, which is worth a thought. If placement is the constraint - a corner, behind a sofa, under a desk - KEF KUBE 10b 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.