In this review, we will be comparing Dynamo 12 and KC92, 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 Dynamo 12 and KEF KC92 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.MartinLogan Dynamo 12 and KEF KC92 have a totally different setup: the MartinLogan Dynamo 12 features 1 x 12-inch drivers whereas the KC92 features 2 x 9-inch drivers.
Frequency Response
Dynamo 12 has a frequency range of 22-200 Hz whereas KC92 has a frequency range of 11-200 Hz. With a minimum frequency of 11Hz, the KC92 can go significantly deeper on the low side and provide stronger bass compared to the Dynamo 12's min frequency of 22Hz.
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 MartinLogan Dynamo 12's and KEF KC92's external dimensions. MartinLogan Dynamo 12 has external dimensions of 425.5 x 400.1 x 455.6mm () whereas KEF KC92 has external dimensions of 352.5 x 330 x 360.5 mm (13.88 x 13.00 x 14.19 in).
MartinLogan Dynamo 12 is clearly the larger of the two speakers. Its body is 70.1mm wider, 73.5mm taller and 94.6mm deeper than KEF KC92.
Size, drawn to scale
Both speakers 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 surface and pushed back to the same wall, so the deeper one visibly sticks out further.
MartinLogan Dynamo 12 needs about 53% more floor or shelf area. MartinLogan Dynamo 12 is 95mm deeper, so it stands that much further out from the wall. MartinLogan Dynamo 12 is 74mm taller.
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 Dynamo 12 is approximately 1822.9cm2 / 282.5inch2 and base area of the KEF KC92 is approximately 1191.3cm2 / 184.7inch2. The Dynamo 12 requires 53% more surface area than the KC92 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 Dynamo 12 weighs 27.90kg / 61.4lbs and the KEF KC92 weighs 20.00kg / 44lbs. This makes the Dynamo 12 40% heavier than the KC92.
Here is a comparison of how Dynamo 12 and KC92's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
 Woofer Size |
12 inches
vs
9 inches
|
Larger woofer |
 Price per pair* |
1600USD
vs
1999USD
|
costs less (*prices may change depending on the seller, location and time) |
| Number of Woofers |
2
vs
1
|
More woofers |
| Low Frequency Response |
11 Hz
vs
22 Hz
|
Generates deeper bass |
 Height |
352mm
vs
425mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1191cm2
vs
1822cm2
|
Takes less floor space |
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 Dynamo 12 needs about 53% more floor area. MartinLogan Dynamo 12 stands 95mm further into the room. MartinLogan Dynamo 12 is 74mm taller.
| General |
MartinLogan Dynamo 12 |
KEF KC92 |
| Brand |
MartinLogan |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Frequency Response |
22-200 Hz |
11-200 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
800-watt RMS |
1000-watt RMS |
| Watts Peak (Max) |
1600-watt RMS |
n/a |
Drivers |
|
|
| Woofer Quantity |
1 |
2 |
| Woofer Size |
12" |
9" |
| Woofer Composition |
|
Polypropylene |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
40-140 Hz |
Physical Specs |
|
|
| Height |
425.5mm (16.8") |
352.0mm (13.9") |
| Width |
400.1mm (15.8") |
330.0mm (13") |
| Depth |
455.6mm (17.9") |
361.0mm (14.2") |
| Weight |
27.90kg (61.4lbs) |
20.00kg (44lbs) |
| Enclosure |
|
Acoustic Suspension |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
3 Years w/ registration |
2 Years |
| Labor Warranty |
3 Years 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 | B | KEF KC92 goes deeper - 11Hz against 22Hz. Under 20Hz is felt more than heard - the bottom of a pipe organ and the bottom of a film mix. |
| Amplifier power | B | KEF KC92 has the bigger amplifier - 1000W against 800W RMS, about 1dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | evenly matched | Near-identical radiating area (12" against 2 x 9"). |
| Enclosure | evenly matched | Both are sealed designs, so they roll off in much the same way. |
| Cabinet size | depends | KEF KC92 is about 46% 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 Dynamo 12 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 | A | MartinLogan Dynamo 12 costs less - $1,600 against $1,999, about 20% less. |
A MartinLogan Dynamo 12 B KEF KC92
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 KC92 measures better, MartinLogan Dynamo 12 costs about 20% less. In a normal room, placement will make a bigger difference than the gap between these two. If placement is the constraint - a corner, behind a sofa, under a desk - KEF KC92 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.