In this review, we will be comparing Dynamo 800X and KUBE 8b, two Powered Subwoofer speakers from MartinLogan 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 MartinLogan 800X 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.Both MartinLogan 800Xand KEF KUBE 8b have a single woofer setup however the MartinLogan 800X's woofer is 10-inch whereas the KEF KUBE 8b features a 8-inch woofer.
Frequency Response
Dynamo 800X has a frequency range of 24-200 Hz whereas KUBE 8b has a frequency range of 34-140 Hz. With a minimum frequency of 24Hz, the Dynamo 800X 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
Both MartinLogan 800X 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 MartinLogan 800X's and KEF KUBE 8b's external dimensions. MartinLogan 800X has external dimensions of 351.0 x 318.0 x 350.0mm (13-13/16 x 12-1/2 x 13-3/4inch) 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).
MartinLogan 800X is clearly the larger of the two speakers. Its body is 22mm wider, 57mm taller and 11mm deeper than KEF KUBE 8b.
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 MartinLogan 800X is approximately 1113.0cm2 / 172.5inch2 and base area of the KEF KUBE 8b is approximately 1003.4cm2 / 155.5inch2. The Dynamo 800X requires 11% 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 MartinLogan 800X weighs 13.64kg / 30lbs and the KEF KUBE 8b weighs 11.36kg / 25lbs. This makes the Dynamo 800X 20% heavier than the KUBE 8b.
Here is a comparison of how Dynamo 800X 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 MartinLogan 800X?
Here are the items that are included inside the box of Dynamo 800X:
- Powered subwoofer
- Grille
- 6.5-feet AC power cord
- User-feets 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
 Woofer Size |
10 inches
vs
8 inches
|
Larger woofer |
| Low Frequency Response |
24 Hz
vs
34 Hz
|
Generates deeper bass |
 High Frequency Response |
200 Hz
vs
140 Hz
|
Generates higher frequency |
 App-Based Control |
iOS,Android
vs
None
|
Control the speaker via an app |
 Wireless Operation |
Optional
vs
No
|
Connect your subwoofer to your system wireless |
 Height |
294mm
vs
351mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1003cm2
vs
1113cm2
|
Takes less floor space |
 Price per pair* |
600USD
vs
900USD
|
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.
MartinLogan 800X needs about 11% more floor area. MartinLogan 800X is 57mm taller.
| General |
MartinLogan Dynamo 800X |
KEF KUBE 8b |
| Brand |
MartinLogan |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
300 watts |
300 watts |
| Frequency Response |
24-200 Hz |
34-140 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
300-watt RMS |
300-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
10" |
8" |
| Woofer Composition |
Polypropylene |
|
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
40-140 Hz |
| Firing Direction |
front and bottom |
front |
Physical Specs |
|
|
| Height |
351.0mm (13.8") |
294.0mm (11.6") |
| Width |
318.0mm (12.5") |
296.0mm (11.7") |
| Depth |
350.0mm (13.8") |
339.0mm (13.3") |
| Weight |
13.64kg (30lbs) |
11.36kg (25lbs) |
| Enclosure |
Acoustic Suspension |
Acoustic Suspension |
| Available Colors |
Satin Black |
n/a |
| Grille |
Yes |
n/a |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
3 Yrs w/ Registration |
2 Years |
| Labor Warranty |
3 Yrs w/ Registration |
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 | A | MartinLogan 800X goes deeper - 24Hz against 34Hz. That gap covers the lowest notes of a five-string bass and a concert bass drum. |
| Amplifier power | evenly matched | Much the same amplifier (300W vs 300W RMS) - under 1dB apart. |
| Driver area | A | MartinLogan 800X moves more air: 10" against 8" is 1.56x the cone area, not the 1.25x 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. |
| Setup and tuning | evenly matched | The same tuning tools on both (room correction). |
| Speaker-level inputs | A | MartinLogan 800X 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. |
| Wireless option | depends | Only MartinLogan 800X offers a wireless link (as a paid option). It decides where the sub can go if you cannot run a cable, and is worth nothing if you can. |
| Driver placement | depends | MartinLogan 800X fires front/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. |
| Cabinet size | depends | KEF KUBE 8b is about 24% 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 | MartinLogan 800X 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 $900, about 33% less. |
A MartinLogan 800X 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: MartinLogan 800X measures better, KEF KUBE 8b costs about 33% less. In a normal room, placement will make a bigger difference than the gap between these two. Check your amplifier first: if it has no subwoofer or preamp output, MartinLogan 800X 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.