In this review, we will be comparing Dynamo 12 and Monitor XT12, two Powered Subwoofer speakers from MartinLogan and Polk Audio. 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 Polk Monitor XT12 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 12and Polk Monitor XT12 have the same driver set up: Both subwoofers have 1 x 12" drivers.
Frequency Response
Dynamo 12 has a frequency range of 22-200 Hz whereas Monitor XT12 has a frequency range of 24-160 Hz. With a minimum frequency of 22Hz, the Dynamo 12 can go slightly deeper then the Monitor XT12'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
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 Polk Monitor XT12's external dimensions. MartinLogan Dynamo 12 has external dimensions of 425.5 x 400.1 x 455.6mm () whereas Polk Monitor XT12 has external dimensions of 418.0 x 408.0 x 485.0mm (16-7/16inch x 16-1/16inch x 19-1/16inch).
MartinLogan Dynamo 12 is 7.9mm narrower and 29.4mm less deeper than Polk Monitor XT12 but it is also 7.5mm taller.
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.
Polk Monitor XT12 needs about 9% more floor or shelf area. Polk Monitor XT12 is 29mm deeper, so it stands that much further out from the wall.
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 Polk Monitor XT12 is approximately 1978.8cm2 / 306.7inch2. The Dynamo 12 requires 8% less surface area than the Monitor XT12 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 MartinLogan Dynamo 12 weighs 27.90kg / 61.4lbs and the Polk Monitor XT12 weighs 17.73kg / 39lbs. This makes the Dynamo 12 57% heavier than the Monitor XT12.
Here is a comparison of how Dynamo 12 and Monitor XT12's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
 Low Frequency Response |
22 Hz
vs
24 Hz
|
Generates deeper bass |
 High Frequency Response |
200 Hz
vs
160 Hz
|
Generates higher frequency |
 Base Surface Area |
1822cm2
vs
1978cm2
|
Takes less floor space |
 Height |
418mm
vs
425mm
|
Easier to fit in smaller spaces |
 Price per pair* |
399USD
vs
1600USD
|
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.
Polk Monitor XT12 needs about 9% more floor area. Polk Monitor XT12 stands 29mm further into the room.
| General |
MartinLogan Dynamo 12 |
Polk Monitor XT12 |
| Brand |
MartinLogan |
Polk Audio |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Frequency Response |
22-200 Hz |
24-160 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
800-watt RMS |
50-watt RMS |
| Watts Peak (Max) |
1600-watt RMS |
n/a |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
12" |
12" |
| Woofer Composition |
|
Bi-laminate paper |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
n/a |
front |
Physical Specs |
|
|
| Height |
425.5mm (16.8") |
418.0mm (16.5") |
| Width |
400.1mm (15.8") |
408.0mm (16.1") |
| Depth |
455.6mm (17.9") |
485.0mm (19.1") |
| Weight |
27.90kg (61.4lbs) |
17.73kg (39lbs) |
| Enclosure |
|
Bass Reflex |
| Grille |
n/a |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
3 Years w/ registration |
3 Years |
| Labor Warranty |
3 Years w/ registration |
3 Years |
A sealed subwoofer against a ported 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 | evenly matched | Effectively the same reach (22Hz vs 24Hz). |
| Amplifier power | A | MartinLogan Dynamo 12 has the bigger amplifier - 800W against 50W RMS, about 12dB 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 12"). |
| Enclosure | depends | MartinLogan Dynamo 12 is sealed - a sealed box rolls off gently and is usually the easier one to integrate in a small or awkward room; Polk Monitor XT12 is ported - a ported box gives more output low down for its size, at the cost of a steeper roll-off below tuning. Neither is better in the abstract; ported tends to suit films and sealed tends to suit music, and both generalisations have exceptions. |
| Price | B | Polk Monitor XT12 costs less - $399 against $1,600, about 75% less. |
A MartinLogan Dynamo 12 B Polk Monitor XT12
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?
MartinLogan Dynamo 12 is ahead, but on only 1 of the measured areas, and it costs about 4x the price. Polk Monitor XT12 is the sensible buy unless your room is large enough to need the extra. Films or music? If this is mainly a home cinema, Polk Monitor XT12 will hit harder for the money; if it is mainly for music in a normal-sized room, MartinLogan Dynamo 12 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 $399 each, two Polk Monitor XT12 cost about $798 against $1,600 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.