In this review, we will be comparing Motion B10 and XT20, two Passive Bookshelf speakers from MartinLogan and Polk Audio.
Let's have a brief look at the main features
of MartinLogan Motion B10 and Polk XT20 first before getting into our more
detailed comparison.
MartinLogan Motion B10 Key Specs
- 2-way Design
- 1.0 x 1.4" Folded Motion Ribbon Tweeter
- 5.25" Woven Fiberglass Woofer
- 56-25k Hz Frequency Response
- 92 dB Sensitivity
- Impedance: 5ohms
- Power Range:20-200watts
- Weight:6.60kg
- Dimensions (H x W x D): 318.0" x 7" x 9-3/4"( 318 x 178 x 248mm )
Polk XT20 Key Specs
- 2-way Design
- 1" Soft-Dome Tweeter
- 6.5" Bi-laminate paper Woofer
- 38-40k Hz Frequency Response
- 87 dB Sensitivity
- Impedance: 8ohms
- Power Range:30-200watts
- Weight:5.45kg
- Dimensions (H x W x D): 332.0" x 7-9/16" x 11-1/16"( 332.0 x 193.0 x 281.0mm )
What size room are the MartinLogan Motion B10 and Polk XT20 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* |
MartinLogan Motion B10 |
Polk XT20 |
| 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 MartinLogan Motion B10 and Polk XT20 compare and hopefully end up with enough arguments to decide which one of these loudspeakers is the better choice for you.
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through my links. As an Amazon Associate I earn from qualifying purchases.
Drivers
Both Motion B10 and XT20 are 2-way speakers.
| Driver |
MartinLogan Motion B10 |
Polk XT20 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1.0 x 1.4-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5.25-inch
|
1 x 6.5-inch
|
Motion B10 features a 1.0 x 1.4" Folded Motion Ribbon Tweeter and 1 x 5.25" Woven Fiberglass Woofer with a Crossover frequency at 2370Hz. On the other hand, the XT20 features a 1" Soft-Dome Tweeter and 1 x 6.5" Bi-laminate paper Woofer .
Frequency Response
Motion B10 has a frequency range of 56-25k Hz whereas XT20 has a frequency range of 38-40k Hz. With a minimum frequency of 38Hz, the XT20 can go significantly deeper on the low side and provide stronger bass compared to the Motion B10's min frequency of 56Hz.
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
Motion B10 is a 5 ohms speaker compared to the XT20 which has a nominal impedance of 8 ohms.
These two speakers also have different sensitivity levels. Motion B10 sensitivity is rated at 92 dB and the XT20's is rated at 87 dB. This 5 dB difference makes the MartinLogan Motion B10 a more sensitive speaker compared to Polk XT20, hence will play louder with the same amount of watts.
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.
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
Motion B10 features 5-Way post type posts and XT20 has a 5-Way post type posts. None of these speakers feature bi-amping/bi-wiring.
MartinLogan Motion B10's Custom 5-way binding posts 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 MartinLogan Motion B10's and Polk XT20's external dimensions. MartinLogan Motion B10 has external dimensions of 318 x 178 x 248mm ( 12-1/2inch x 7inch x 9-3/4inch ) whereas Polk XT20 has external dimensions of 332.0 x 193.0 x 281.0mm ( 13-1/16 x 7-9/16 x 11-1/16inch) .
Polk XT20 is clearly the larger of the two speakers. Its body is 15mm wider, 14mm taller and 33mm deeper than MartinLogan Motion B10.
Below you can see the front view size comparison of MartinLogan Motion B10 and Polk XT20 in scale.
Comparison image of MartinLogan Motion B10 and Polk XT20 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 MartinLogan Motion B10 is approximately 441.4cm2 / 68.4inch2 and base area of the Polk XT20 is approximately 542.3cm2 / 84.1inch2. The Motion B10 requires 19% less surface area than the XT20 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 MartinLogan Motion B10 and Polk XT20 on a Media Console