In this review, we will be comparing KC62 and Dynamo 800X, two Powered Subwoofer speakers from KEF and MartinLogan. 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 KC62 and MartinLogan 800X 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 KC62 and MartinLogan 800X have a totally different setup: the KEF KC62 features 2 x 6.5-inch drivers whereas the Dynamo 800X features 1 x 10-inch drivers.
Frequency Response
KC62 has a frequency range of 11-200 Hz whereas Dynamo 800X has a frequency range of 24-200 Hz. With a minimum frequency of 11Hz, the KC62 can go significantly deeper on the low side and provide stronger bass compared to the Dynamo 800X's min frequency of 24Hz.
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 KEF KC62 and MartinLogan 800X 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 KEF KC62's and MartinLogan 800X's external dimensions. KEF KC62 has external dimensions of 245.0 x 258.0 x 281.0mm (9-5/8inch x 10-1/8inch x 11-1/16inch) whereas 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).
MartinLogan 800X is clearly the larger of the two speakers. Its body is 60mm wider, 106mm taller and 69mm deeper than KEF KC62.
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 KC62 is approximately 725.0cm2 / 112.4inch2 and base area of the MartinLogan 800X is approximately 1113.0cm2 / 172.5inch2. The KC62 requires 35% less surface area than the Dynamo 800X 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 KEF KC62 weighs 14.05kg / 30.9lbs and the MartinLogan 800X weighs 13.64kg / 30lbs. This makes the KC62 3% heavier than the Dynamo 800X.
Here is a comparison of how KC62 and Dynamo 800X'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 KC62?
Here are the items that are included inside the box of KC62:
- 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 MartinLogan 800X?
Here are the items that come with the Dynamo 800X:
- Powered subwoofer
- Grille
- 6.5-feet AC power cord
- User-feets Manual
 Number of Woofers |
2
vs
1
|
More woofers |
| Low Frequency Response |
11 Hz
vs
24 Hz
|
Generates deeper bass |
 Height |
245mm
vs
351mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
725cm2
vs
1113cm2
|
Takes less floor space |
| Woofer Size |
10 inches
vs
6.5 inches
|
Larger woofer |
 App-Based Control |
iOS,Android
vs
None
|
Control the speaker via an app |
 Price per pair* |
900USD
vs
1500USD
|
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 54% more floor area. MartinLogan 800X stands 69mm further into the room. MartinLogan 800X is 106mm taller.
| General |
KEF KC62 |
MartinLogan Dynamo 800X |
| Brand |
KEF |
MartinLogan |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
1000 watts |
300 watts |
| Frequency Response |
11-200 Hz |
24-200 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
1000-watt RMS |
300-watt RMS |
Drivers |
|
|
| Woofer Quantity |
2 |
1 |
| Woofer Size |
6.5" |
10" |
| Woofer Composition |
|
Polypropylene |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
side |
front and bottom |
Physical Specs |
|
|
| Height |
245.0mm (9.6") |
351.0mm (13.8") |
| Width |
258.0mm (10.2") |
318.0mm (12.5") |
| Depth |
281.0mm (11.1") |
350.0mm (13.8") |
| Weight |
14.05kg (30.9lbs) |
13.64kg (30lbs) |
| Enclosure |
Acoustic Suspension |
Acoustic Suspension |
| Available Colors |
n/a |
Satin Black |
| Grille |
n/a |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
2 Years |
3 Yrs w/ Registration |
| Labor Warranty |
2 Years |
3 Yrs w/ Registration |
Different price classes - KEF KC62 costs roughly 1.7x what MartinLogan 800X does. Before paying it, read the note below about two smaller subwoofers.
| Area | Better | Why |
|---|
| Bass depth | A | KEF KC62 goes deeper - 11Hz against 24Hz. Under 20Hz is felt more than heard - the bottom of a pipe organ and the bottom of a film mix. |
| Amplifier power | A | KEF KC62 has the bigger amplifier - 1000W against 300W RMS, about 5.2dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | evenly matched | Near-identical radiating area (2 x 6.5" against 10"). |
| 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). |
| Driver placement | depends | KEF KC62 fires side and MartinLogan 800X fires front/down. 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 KC62 is about 55% 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 | B | 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 | MartinLogan 800X costs less - $900 against $1,500, about 40% less. |
A KEF KC62 B MartinLogan 800X
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?
KEF KC62 is ahead, but on only 1 of the measured areas, and it costs about 67% more. MartinLogan 800X is the sensible buy unless your room is large enough to need the extra. 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 $900 each, two MartinLogan 800X cost about $1,800 against $1,500 for one of the other, which is worth a thought. If placement is the constraint - a corner, behind a sofa, under a desk - KEF KC62 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.