In this review, we will be comparing Monitor XT12 and KF92, two Powered Subwoofer speakers from Polk Audio 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 Polk Monitor XT12 and KEF KF92 first before getting into our more detailed comparison.
In the following sections, we will get into details in order to better understand how the Polk Monitor XT12 and KEF KF92 compare and hopefully end up with enough arguments to decide which one of these subwoofers is the better choice for you.
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Drivers
The efficiency of a subwoofer is directly proportional to the total radiating are squared hence the woofer quantity and diameter.Polk Monitor XT12 and KEF KF92 have a totally different setup: the Polk Monitor XT12 features 1 x 12-inch drivers whereas the KF92 features 2 x 9-inch drivers.
Frequency Response
Monitor XT12 has a frequency range of 24-160 Hz whereas KF92 has a frequency range of 11-200 Hz. With a minimum frequency of 11Hz, the KF92 can go significantly deeper on the low side and provide stronger bass compared to 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 KEF KF92 have Acoustic Suspension type enclosure. 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
Size of a speaker can sometimes become 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 KEF KF92'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 KEF KF92 has external dimensions of 353.0 x 331.0 x 362.0mm ( 13-7/8 x 13 x 14-1/4inch) .
Polk Monitor XT12 is clearly the larger of the two speakers. Its body is 77mm wider, 65mm taller and 123mm deeper than KEF KF92.
Below you can see the front view size comparison of Polk Monitor XT12 and KEF KF92 in scale.
Comparison image of Polk Monitor XT12 and KEF KF92 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 KEF KF92 is approximately 1198.2cm2 / 185.7inch2. The Monitor XT12 requires 65% more surface area than the KF92 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 Polk Monitor XT12 weighs 17.73kg / 39lbs and the KEF KF92 weighs 20.05kg / 44.1lbs. This makes the KF92 13% heavier than the Monitor XT12.
Here is a comparison of how Monitor XT12 and KF92'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 subwoofer6.5-feet AC power cordGrilleOwners ManualOnline registration card
What's in the Box of KEF KF92?
Here are the items that come with the KF92:
Powered subwoofer6.5-feet AC power cordSpeaker-level input blockUser ManualImportant Safety InformationWarranty Information
 Woofer Size |
12 inches
vs
9 inches
|
Larger woofer |
 Price per pair* |
399USD
vs
2000USD
|
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
24 Hz
|
Generates deeper bass |
 High Frequency Response |
200k Hz
vs
160k Hz
|
Generates higher frequency |
 Height |
353mm
vs
418mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1198cm2
vs
1978cm2
|
Takes less floor space |
| General |
Polk Monitor XT12 |
KEF KF92 |
| Brand |
Polk Audio |
KEF |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
50 watts |
1000 watts |
| Frequency Response |
24-160 Hz |
11-200 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
50-watt RMS |
1000-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
2 |
| Woofer Size |
12" |
9" |
| Woofer Composition |
Bi-laminate paper |
Hybrid aluminum |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
front |
n/a |
Physical Specs |
|
|
| Height |
418.0mm (16.5") |
353.0mm (13.9") |
| Width |
408.0mm (16.1") |
331.0mm (13") |
| Depth |
485.0mm (19.1") |
362.0mm (14.3") |
| Weight |
17.73kg (39lbs) |
20.05kg (44.1lbs) |
| Enclosure |
Bass Reflex |
Acoustic Suspension |
| Grille |
Yes |
n/a |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
3 Years |
2 Years |
| Labor Warranty |
3 Years |
2 Years |