In this review, we will be comparing Monitor XT12 and C 912, two Powered Subwoofer speakers from Polk Audio and Jamo. 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 Jamo C 912 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.Polk Monitor XT12and Jamo C 912 have the same driver set up: Both subwoofers have 1 x 12" drivers.
Frequency Response
Monitor XT12 has a frequency range of 24-160 Hz whereas C 912 has a frequency range of 29-125 Hz. With a minimum frequency of 24Hz, the Monitor XT12 can go significantly deeper on the low side and provide stronger bass compared to the C 912's min frequency of 29Hz.
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 Polk Monitor XT12 and Jamo C 912 have Bass Reflex type cabinets. 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.
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 Jamo C 912'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 Jamo C 912 has external dimensions of 461.0 x 358.0 x 507.0mm (18-1/8 x 14-1/16 x 19-15/16inch).
Polk Monitor XT12 is 43mm shorter and 22mm less deeper than Jamo C 912 but it is also 50mm wider.
Below you can see the front view size comparison of Polk Monitor XT12 and Jamo C 912 in scale.
Comparison image of Polk Monitor XT12 and Jamo C 912 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 Jamo C 912 is approximately 1815.1cm2 / 281.3inch2. The Monitor XT12 requires 9% more surface area than the C 912 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 Jamo C 912 weighs 18.98kg / 41.8lbs. This makes the C 912 7% heavier than the Monitor XT12.
Here is a comparison of how Monitor XT12 and C 912'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 Jamo C 912?
Here are the items that come with the C 912:
- Powered subwoofer
- Grille
- 6-feet AC power cord
- User Manual
- Important Safety Instructions
- Warranty Information
 Low Frequency Response |
24 Hz
vs
29 Hz
|
Generates deeper bass |
 High Frequency Response |
160 Hz
vs
125 Hz
|
Generates higher frequency |
 Height |
418mm
vs
461mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
1815cm2
vs
1978cm2
|
Takes less floor space |
 Price per pair* |
229USD
vs
399USD
|
costs less (*prices may change depending on the seller, location and time) |
 Wireless Operation |
Optional
vs
No
|
Connect your subwoofer to your system wireless |
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. Jamo C 912 stands 22mm further into the room. Jamo C 912 is 43mm taller.
| General |
Polk Monitor XT12 |
Jamo C 912 |
| Brand |
Polk Audio |
Jamo |
| Speaker Type |
Powered Subwoofer |
Powered Subwoofer |
| Max Amplifier Output |
50 watts |
200 watts |
| Frequency Response |
24-160 Hz |
29-125 Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
50-watt RMS |
200-watt RMS |
| Watts Peak (Max) |
n/a |
400-watt RMS |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
12" |
12" |
| Woofer Composition |
Bi-laminate paper |
IMG |
| Tweeter Size |
- |
- |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
front |
front |
Physical Specs |
|
|
| Height |
418.0mm (16.5") |
461.0mm (18.1") |
| Width |
408.0mm (16.1") |
358.0mm (14.1") |
| Depth |
485.0mm (19.1") |
507.0mm (20") |
| Weight |
17.73kg (39lbs) |
18.98kg (41.8lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
3 Years |
2 Years |
| Labor Warranty |
3 Years |
2 Years |
Different price classes - Polk Monitor XT12 costs roughly 1.7x what Jamo C 912 does. Before paying it, read the note below about two smaller subwoofers.
| Area | Better | Why |
|---|
| Bass depth | A | Polk Monitor XT12 goes deeper - 24Hz against 29Hz. A real difference, though most music has little content below 29Hz. |
| Amplifier power | B | Jamo C 912 has the bigger amplifier - 200W against 50W RMS, about 6dB 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 | evenly matched | Both are ported designs, so they roll off in much the same way. |
| Speaker-level inputs | A | Polk Monitor XT12 takes a speaker-level connection as well as line level. That is what lets it work with an integrated amplifier or a vintage receiver that has no subwoofer output at all. |
| Wireless option | depends | Only Jamo C 912 offers a wireless link (as a paid option). It decides where the sub can go if you cannot run a cable, and is worth nothing if you can. |
| Warranty | A | Polk Monitor XT12 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 | Jamo C 912 costs less - $229 against $399, about 43% less. |
A Polk Monitor XT12 B Jamo C 912
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: Polk Monitor XT12 measures better, Jamo C 912 costs about 43% less. In a normal room, placement will make a bigger difference than the gap between these two. Check your amplifier first: if it has no subwoofer or preamp output, Polk Monitor XT12 is the only one of these two you can connect at all. 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 $229 each, two Jamo C 912 cost about $458 against $399 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.