In this review, we will be comparing XT15 and A120, two Passive Bookshelf speakers from Polk Audio and JBL.
Let's have a brief look at the main features
of Polk XT15 and JBL A120 first before getting into our more
detailed comparison.
Polk XT15 Key Specs
- 2-way Design
- 1" Soft-Dome Tweeter
- 5.25" Bi-laminate paper Woofer
- 48-40k Hz Frequency Response
- 86 dB Sensitivity
- Impedance: 8ohms
- Power Range:30-150watts
- Weight:4.09kg
- Dimensions (H x W x D): 270.0" x 6-9/16" x 7-3/16"( 270.0 x 167.0 x 183.0mm )
JBL A120 Key Specs
- 2-way Design
- 1" Hard-Dome Tweeter
- 4.5" Polycellulose Woofer
- 60-40k Hz Frequency Response
- 86 dB Sensitivity
- Impedance: 6ohms
- Power Range:20-125watts
- Weight:3.82kg
- Dimensions (H x W x D): 286.0" x 6-3/4" x 7-7/16"( 286.0 x 172.0 x 189.0mm )
What size room are the Polk XT15 and JBL A120 speakers good for?
The size of the room in which you are planning to use these loudspeakers is an important decision
factor. Here we have compared their suitability to various sizes of environments considering their size
and max power parameters:
| Listening Environment* |
Polk XT15 |
JBL A120 |
| Near-field |
Poor |
Poor |
| Small Room |
Average |
Average |
| Mid-size Room |
Good |
Good |
| Large Room |
Average |
Average |
| Very Large Room |
Poor |
Poor |
(* Approximate Room sizes: Small < 100sq. ft / 9 m2,
Mid-size: 100-220 sq. ft / 9-20 m2, Large 220-400 sq. ft / 20-36 m2, Very Large: >
400 sq. ft / 36 m2.
Average Floor Height: 9" / 2.7m. Typical room sizes differ from country to country, and the actual
listening experience changes depending on floor height, room shape, surface materials, listening
position, speaker locations, etc.)
In the following sections, we will get into more detail in order to better understand how the Polk XT15 and JBL A120 compare and hopefully end up with enough arguments to decide which one of these loudspeakers is the better choice for you.
**This post contains affiliate links, and I will be compensated if you make a purchase after clicking
through my links. As an Amazon Associate I earn from qualifying purchases.
Drivers
Both XT15 and A120 are 2-way speakers.
| Driver |
Polk XT15 |
JBL A120 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5.25-inch
|
1 x 4.5-inch
|
XT15 features a 1" Soft-Dome Tweeter and 1 x 5.25" Bi-laminate paper Woofer . On the other hand, the A120 features a 1" aluminum Hard-Dome Tweeter and 1 x 4.5" Polycellulose Woofer .
Frequency Response
XT15 has a frequency range of 48-40k Hz whereas A120 has a frequency range of 60-40k Hz. With a minimum frequency of 48Hz, the XT15 can go significantly deeper on the low side and provide stronger bass compared to the A120's min frequency of 60Hz.
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 Bookshelf class in our database.
Low Frequency
Bookshelf Speakers
High Frequency
Bookshelf Speakers
None of these speakers achieves full range experience which is commonly agreed as 20Hz-20kHz. In order to achieve lower lows / deeper bass, we recommend you pair these with a subwoofer. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
XT15 is a 8 ohms speaker compared to the A120 which has a nominal impedance of 6 ohms.
On the other hand, they have the same sensitivity of 86 dBdB.
Sensitivity
Bookshelf Speakers
Power Range
Power
range is the range of input power in watts RMS that a loudspeaker is designed to handle. While using
an amplifier within this range ensures the nominal performance , inputting a power that is higher than the
max wattage can result in a damaged speaker.
XT15 can handle a max power of 150 watts RMS from the amp the whereas A120 has a max power handling value of 125 watts RMS, 25 watts less than the XT15.
Keep in mind that a higher max power handling value doesn't necessarily make that a louder speaker
compared to a lower max handling speaker. Loudness or the sound level is also impacted by parameters
such as Impedance, sensitivity and system efficiencies.
Input Type and Bi-Amping / Bi-Wiring
XT15 features 5-way post type posts and A120 has a 5-way post type posts. None of these speakers feature bi-amping/bi-wiring.
JBL A120's 5-way post terminals
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 XT15's and JBL A120's external dimensions. Polk XT15 has external dimensions of 270.0 x 167.0 x 183.0mm ( 10-5/8 x 6-9/16 x 7-3/16inch) whereas JBL A120 has external dimensions of 286.0 x 172.0 x 189.0mm ( 11-1/4 x 6-3/4 x 7-7/16inch) .
JBL A120 is clearly the larger of the two speakers. Its body is 5mm wider, 16mm taller and 6mm deeper than Polk XT15.
Below you can see the front view size comparison of Polk XT15 and JBL A120 in scale.
Comparison image of Polk XT15 and JBL A120 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 XT15 is approximately 305.6cm2 / 47.4inch2 and base area of the JBL A120 is approximately 325.1cm2 / 50.4inch2. The XT15 requires 6% less surface area than the A120 which gives it a small advantage on placement in tight spaces.
Here is an another comparison that shows both speakers on a BDI Octave Media Cabinet, next to a standard size amplifier and turntable in scale:
Size Comparison image of Polk XT15 and JBL A120 on a Media Console
Weight Comparison The weight of a loudspeaker can become an important factor if you need to move and reposition the unit often. Weight of a speaker can also "sometimes" be an indicator of the rigidity of the enclosure and the quality of the internal components used. The Polk XT15 weighs 4.09kg / 9lbs and the JBL A120 weighs 3.82kg / 8.4lbs. This makes the XT15 7% heavier than the A120.
Here is a comparison of how XT15 and A120's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of Polk XT15?
Here are the items that are included inside the box of XT15:
2 Bookshelf loudspeakers2 Grilles (attached)8 Self-adhesive rubber feetOwners ManualOnline Product Registration
What's in the Box of JBL A120?
Here are the items that come with the A120:
2 Bookshelf loudspeakers2 Grilles2 Foam plugs4 Brackets8 Rubber feet8 Screws (M6 x 8mm)Owner-feets ManualWarranty Card
 Max Input Power |
150 watts
vs
125 watts
|
Handle more power from your amplifier |
 Nominal Impedance |
8 ohms
vs
6 ohms
|
Less selective with amplifiers |
 Woofer Size |
5.25 inches
vs
4.5 inches
|
Larger woofer |
|
Low Frequency Response |
48 Hz
vs
60 Hz
|
Generates deeper bass |
 Height |
270mm
vs
286mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
305cm2
vs
325cm2
|
Takes less floor space |
 Price per pair* |
199USD
vs
250USD
|
costs less (*prices may change depending on the seller, location and time) |
 Mounting Bracket |
Yes
vs
No
|
Allows mounting on walls |
| General |
Polk Audio Monitor XT15 |
JBL Stage A120 |
| Brand |
Polk Audio |
JBL |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
30-150 watts |
20-125 watts |
| Sensitivity |
86 dB |
86 dB |
| Impedance |
8 ohms |
6 ohms |
| Frequency Response |
48-40k Hz |
60-40k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5.25" |
4.5" |
| Woofer Composition |
Bi-laminate paper |
Polycellulose |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Soft-Dome |
Hard-Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
n/a |
rear |
Physical Specs |
|
|
| Height |
270.0mm (10.6") |
286.0mm (11.3") |
| Width |
167.0mm (6.6") |
172.0mm (6.8") |
| Depth |
183.0mm (7.2") |
189.0mm (7.4") |
| Weight |
4.09kg (9lbs) |
3.82kg (8.4lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF, Vinyl |
MDF, Vinyl |
| Available Colors |
Black |
Black |
| Mounting Bracket |
No |
Keyholes w/ bracket |
| Recommended Stand Height |
28-32" |
26-28" |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
No |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |