In this review, we will be comparing SuperSub X and KUBE 8b, two Powered Subwoofer speakers from GoldenEar 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 GoldenEar SuperSub X 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.
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Drivers
The efficiency of a subwoofer is directly proportional to the total radiating are squared hence the woofer quantity and diameter.GoldenEar SuperSub X and KEF KUBE 8b have a totally different setup: the GoldenEar SuperSub X features 2 x 8-inch drivers whereas the KUBE 8b features 1 x 8-inch drivers.
Frequency Response
SuperSub X has a frequency range of 12-250 Hz whereas KUBE 8b has a frequency range of 34-140 Hz. With a minimum frequency of 12Hz, the SuperSub X 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 GoldenEar SuperSub X has a Passive Radiator type cabinet. 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. 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 GoldenEar SuperSub X's and KEF KUBE 8b's external dimensions. GoldenEar SuperSub X has external dimensions of 324.0 x 356.0 x 388.0mm (12-3/4inch x 14inch x 15-1/4inch) 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).
GoldenEar SuperSub X is clearly the larger of the two speakers. Its body is 60mm wider, 30mm taller and 49mm deeper than KEF KUBE 8b.
Below you can see the front view size comparison of GoldenEar SuperSub X and KEF KUBE 8b in scale.
Comparison image of GoldenEar SuperSub X 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 GoldenEar SuperSub X is approximately 1381.3cm2 / 214.1inch2 and base area of the KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2. The SuperSub X requires 38% 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 GoldenEar SuperSub X weighs 18.18kg / 40lbs and the KEF KUBE 8b weighs 11.36kg / 25lbs. This makes the SuperSub X 60% heavier than the KUBE 8b.
Here is a comparison of how SuperSub X 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 GoldenEar SuperSub X?
Here are the items that are included inside the box of SuperSub X:
- Powered Subwoofer
- 10-feet AC power cord
- Owners Manual
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
 Number of Woofers |
2
vs
1
|
More woofers |
| Low Frequency Response |
12 Hz
vs
34 Hz
|
Generates deeper bass |
 High Frequency Response |
250 Hz
vs
140 Hz
|
Generates higher frequency |
 Passive Radiator |
two 10.5-inch x 9.5-inch
vs
None
|
Increases the bass performance |
 Height |
294mm
vs
324mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1003cm2
vs
1381cm2
|
Takes less floor space |
 Price per pair* |
600USD
vs
1499USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
GoldenEar SuperSub X |
KEF KUBE 8b |
| Brand |
GoldenEar |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
1400 watts |
300 watts |
| Frequency Response |
12-250 Hz |
34-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
1400-watt RMS |
300-watt RMS |
Drivers |
|
|
| Woofer Quantity |
2 |
1 |
| Woofer Size |
8" |
8" |
| Woofer Composition |
Fiber |
|
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
40-140 Hz |
| Firing Direction |
side |
front |
Physical Specs |
|
|
| Height |
324.0mm (12.8") |
294.0mm (11.6") |
| Width |
356.0mm (14") |
296.0mm (11.7") |
| Depth |
388.0mm (15.3") |
339.0mm (13.3") |
| Weight |
18.18kg (40lbs) |
11.36kg (25lbs) |
| Enclosure |
Passive Radiator |
Acoustic Suspension |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
3 Years |
2 Years |
| Labor Warranty |
3 Years |
2 Years |
A passive radiator subwoofer against a sealed 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 | A | GoldenEar SuperSub X goes deeper - 12Hz against 34Hz. Under 20Hz is felt more than heard - the bottom of a pipe organ and the bottom of a film mix. |
| Amplifier power | A | GoldenEar SuperSub X has the bigger amplifier - 1400W against 300W RMS, about 6.7dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | A | GoldenEar SuperSub X moves more air: 2 x 8" against 8" is 2x the cone area, not the 1.41x the diameters suggest. More area means the same output with less excursion, and less distortion with it. |
| Enclosure | depends | GoldenEar SuperSub X is passive radiator - a passive radiator behaves like a port without the pipe noise, and suits a slim cabinet; 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. Neither is better in the abstract; ported tends to suit films and sealed tends to suit music, and both generalisations have exceptions. |
| Phase control | B | KEF KUBE 8b has a phase control. Without one, the only way to fix a cancellation at the crossover is to move the box. |
| Driver placement | depends | GoldenEar SuperSub X fires side 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. |
| Cabinet size | depends | KEF KUBE 8b is about 34% 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 | GoldenEar SuperSub X 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 8b costs less - $600 against $1,499, about 60% less. |
A GoldenEar SuperSub X 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: GoldenEar SuperSub X measures better, KEF KUBE 8b costs about 60% less. In a normal room, placement will make a bigger difference than the gap between these two. Films or music? If this is mainly a home cinema, GoldenEar SuperSub X 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. 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 $600 each, two KEF KUBE 8b cost about $1,200 against $1,499 for one of the other, which is worth a thought.
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.