In this review, we will be comparing Monitor XT12 and Descend DN15, two Powered Subwoofer speakers from Polk Audio and Definitive Technology. 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 Polk Monitor XT12 and Definitive DN15 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 Polk Monitor XT12and Definitive DN15 have a single woofer setup however the Polk Monitor XT12's woofer is 12-inch whereas the Definitive DN15 features a 15-inch woofer.
Frequency Response
Monitor XT12 has a frequency range of 24-160 Hz whereas Descend DN15 has a frequency range of 20-150 Hz. With a minimum frequency of 20Hz, the Descend DN15 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
Cabinet Type
The Polk Monitor XT12 has a Bass Reflex type cabinet. Bass Reflex type subwoofers (aka Ported, Vented or Reflex Port) have enclosures that uses a port, hole or vent cut into the cabinet. Ported designs are generally more efficient than the Sealed designs. On the other hand the Definitive DN15 have Passive Radiator type enclosure. 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.
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 Polk Monitor XT12's and Definitive DN15's external dimensions. 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) whereas Definitive DN15 has external dimensions of 634.0 x 596.0 x 640.0mm (24-15/16inch x 23-7/16inch x 25-3/16inch).
Definitive DN15 is clearly the larger of the two speakers. Its body is 188mm wider, 216mm taller and 155mm deeper than Polk Monitor XT12.
Below you can see the front view size comparison of Polk Monitor XT12 and Definitive DN15 in scale.
Comparison image of Polk Monitor XT12 and Definitive DN15 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 Polk Monitor XT12 is approximately 1978.8cm2 / 306.7inch2 and base area of the Definitive DN15 is approximately 3814.4cm2 / 591.2inch2. The Monitor XT12 requires 48% less surface area than the Descend DN15 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 Polk Monitor XT12 weighs 17.73kg / 39lbs and the Definitive DN15 weighs 52.09kg / 114.6lbs. This makes the Descend DN15 194% heavier than the Monitor XT12.
Here is a comparison of how Monitor XT12 and Descend DN15's weights compare with the average, max and min weights in Powered Subwoofer class.
Weight
All Subwoofer Speakers
What's in the Box of Polk Monitor XT12?
Here are the items that are included inside the box of Monitor XT12:
- Black powered subwoofer
- 6.5-feet AC power cord
- Grille
- Owners Manual
- Online registration card
What's in the Box of Definitive DN15?
Here are the items that come with the Descend DN15:
- Powered subwoofer
- 6-feet AC power cord
- Remote control
- CR2032 3V battery (pre-installed in remote)
- Owners Manual
 High Frequency Response |
160 Hz
vs
150 Hz
|
Generates higher frequency |
 Height |
418mm
vs
634mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1978cm2
vs
3814cm2
|
Takes less floor space |
 Price per pair* |
399USD
vs
1799USD
|
costs less (*prices may change depending on the seller, location and time) |
 Woofer Size |
15 inches
vs
12 inches
|
Larger woofer |
| Low Frequency Response |
20 Hz
vs
24 Hz
|
Generates deeper bass |
 Passive Radiator |
2 x 15-inch
vs
None
|
Increases the bass performance |
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.
Definitive DN15 needs about 93% more floor area. Definitive DN15 stands 155mm further into the room. Definitive DN15 is 216mm taller.
| General |
Polk Monitor XT12 |
Definitive Technology Descend DN15 |
| Brand |
Polk Audio |
Definitive Technology |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
50 watts |
500 watts |
| Frequency Response |
24-160 Hz |
20-150 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
50-watt RMS |
500-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
12" |
15" |
| Woofer Composition |
Bi-laminate paper |
Polypropylene |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
front |
front |
Physical Specs |
|
|
| Height |
418.0mm (16.5") |
634.0mm (25") |
| Width |
408.0mm (16.1") |
596.0mm (23.5") |
| Depth |
485.0mm (19.1") |
640.0mm (25.2") |
| Weight |
17.73kg (39lbs) |
52.09kg (114.6lbs) |
| Enclosure |
Bass Reflex |
Passive Radiator |
| Grille |
Yes |
n/a |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
3 Years |
3 Years |
| Labor Warranty |
3 Years |
3 Years |
A ported subwoofer against a passive radiator 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 | B | Definitive DN15 goes deeper - 20Hz against 24Hz. Under 20Hz is felt more than heard - the bottom of a pipe organ and the bottom of a film mix. |
| Amplifier power | B | Definitive DN15 has the bigger amplifier - 500W against 50W RMS, about 10dB more on tap. In a large room that is headroom before the DSP starts limiting. |
| Driver area | B | Definitive DN15 moves more air: 15" against 12" 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 | depends | 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; Definitive DN15 is passive radiator - a passive radiator behaves like a port without the pipe noise, and suits a slim cabinet. Neither is better in the abstract; ported tends to suit films and sealed tends to suit music, and both generalisations have exceptions. |
| Cabinet size | depends | Polk Monitor XT12 is about 66% 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. |
| Price | A | Polk Monitor XT12 costs less - $399 against $1,799, about 78% less. |
A Polk Monitor XT12 B Definitive DN15
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: Definitive DN15 measures better, Polk Monitor XT12 costs about 78% less. In a normal room, placement will make a bigger difference than the gap between these two. 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 $1,799 for one of the other, which is worth a thought. If placement is the constraint - a corner, behind a sofa, under a desk - Polk Monitor XT12 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.