In this review, we will be comparing Motion XT C100 and L400, two Passive Center Channel speakers from MartinLogan and Polk Audio. Let's have a brief look at the main features
of MartinLogan Motion XT C100 and Polk L400 first before getting into our more
detailed comparison.
What size room are the MartinLogan Motion XT C100 and Polk L400 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:
In the following sections, we will get into more detail in order to better understand how the MartinLogan Motion XT C100 and Polk L400 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
One of the fundamental differences between these two speakers is that Motion XT C100 is a 2-way design whereas the L400 is a 3-way speaker. 3-way designs utilize a midrange driver in addition to the tweeter and woofer on 2-way designs. Designing a crossover for a 3-way speaker is a complicated process and generally increases the overall cost of the speaker.
| Driver |
MartinLogan Motion XT C100 |
Polk L400 |
|
Driver Setup
|
2-way
|
3-way
|
|
Tweeter
|
1.25 x 2.4-inch
|
1-inch
|
|
Midrange
|
- |
1 x 4-inch |
|
Woofer
|
2 x 6.5-inch
|
2 x 6.5-inch
|
Motion XT C100 features a 1.25 x 2.4" Folded Motion XT Tweeter and 2 x 6.5" Aluminum Woofer with a Crossover frequency at 1300Hz and 2500Hz. On the other hand, the L400 features a 1" Pinnacle Ring Radiator Tweeter , a 4" Midrange and 2 x 6.5" Woofer .
Frequency Response
Motion XT C100 has a frequency range of 42-25k Hz whereas L400 has a frequency range of 55-38k Hz. With a minimum frequency of 42Hz, the Motion XT C100 can go significantly deeper on the low side and provide stronger bass compared to the L400's min frequency of 55Hz.
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 Center Channel class in our database.
Low Frequency
Center Channel Speakers
High Frequency
Center Channel Speakers
MartinLogan Motion XT C100
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 XT C100 is a 5 ohms speaker compared to the L400 which has a nominal impedance of 4 ohms. Lower impedance speakers, especially the ones that are rated at 4 ohms may put more pressure on the amplifier unit especially when played at high volume levels, so make sure the amp you pair with the L400 can provide this impedance level.
These two speakers also have different sensitivity levels. Motion XT C100 sensitivity is rated at 93 dB and the L400's is rated at 87.5 dB. This 5 dB difference makes the MartinLogan Motion XT C100 a more sensitive speaker compared to Polk L400, hence will play louder with the same amount of watts.
Sensitivity
Center Channel 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 XT C100 features Custom 5-way bi-wire tool-less binding posts posts which make bi-amping or bi-wiring possible. L400 has a Binding post which doesn't feature bi-amping/bi-wiring.
MartinLogan Motion XT C100's Custom 5-way bi-wire tool-less binding posts terminals allows Bi-amping or bi-wiring
Polk L400's Binding post terminals
Cabinet Type and Port Position
Both Motion XT C100 and L400 have rear firing ports. Rear ported speakers generally need more room between the backside of the speaker and the wall compared to sealed and front/bottom ported speakers. Placing the speakers too close to the walls may cause the bass to sound boomy.
If you are limited in space and can't get the speakers away from the backwall, check our Speakers with Front Firing Ports page.
Polk L400 Port
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 XT C100's and Polk L400's external dimensions. MartinLogan Motion XT C100 has external dimensions of 203 x 610 x 368mm ( 8inch x 24inch x 14-1/2inch ) whereas Polk L400 has external dimensions of 245.0 x 662.0 x 343.0mm ( 9-5/8 x 26-1/16 x 13-1/2inch) .
MartinLogan Motion XT C100 is 52mm narrower and 42mm shorter than Polk L400 but it is also 25mm deeper.
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 XT C100 is approximately 2244.8cm2 / 347.9inch2 and base area of the Polk L400 is approximately 2270.7cm2 / 352.0inch2. The Motion XT C100 requires 1% less surface area than the L400 which gives it a small advantage on placement in tight spaces.
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 MartinLogan Motion XT C100 weighs 15.40kg / 33.9lbs and the Polk L400 weighs 18.55kg / 40.8lbs. This makes the L400 20% heavier than the Motion XT C100.
Here is a comparison of how Motion XT C100 and L400's weights compare with the average, max and min weights in Passive Center Channel class.
Weight
All Center Channel Speakers
MartinLogan Motion XT C100
What's in the Box of Polk L400?
Here are the items that come with the L400:
Center-channel loudspeakerGrille2 Jumper-wiresCleaning clothOwners ManualOnline Registration
 Sensitivity |
93 dB
vs
88 dB
|
Play louder with same amount of amplification power |
 Nominal Impedance |
5 ohms
vs
4 ohms
|
Less selective with amplifiers |
 Low Frequency Response |
42 Hz
vs
55 Hz
|
Generates deeper bass |
 Height |
203mm
vs
245mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
2244cm2 (610x368mm)
vs
2270cm2 (662x343mm)
|
Takes less floor space |
 Driver Setup |
3-way
vs
2-way
|
Have a dedicated mid-range driver |
 High Frequency Response |
38k Hz
vs
25k Hz
|
Generates higher frequency |
 Price per pair* |
1799USD
vs
2998USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
MartinLogan Motion® XT C100 |
Polk Audio Legend L400 |
| Brand |
MartinLogan |
Polk Audio |
| Speaker Type |
Center channel speaker |
Center channel speaker |
| Power Range |
20-300 watts |
25-300 watts |
| Sensitivity |
93 dB |
87.5 dB |
| Impedance |
5 ohms |
4 ohms |
| Frequency Response |
42-25k Hz |
55-38k Hz |
Drivers |
|
|
| Woofer Quantity |
2 |
2 |
| Woofer Size |
6.5" |
6.5" |
| Woofer Composition |
Aluminum |
|
| Woofer Surround Material |
Rubber |
n/a |
| Tweeter Size |
1.25 x 2.4" |
1" |
| Tweeter Type |
Folded Motion XT |
Pinnacle Ring Radiator |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
4" |
| Crossover Frequency |
1300Hz and 2500Hz |
n/a |
| Firing Direction |
rear |
rear |
| Suggested Break-in Period |
Allow 72 hours of break-in |
n/a |
Physical Specs |
|
|
| Height |
203.0mm (8") |
245.0mm (9.6") |
| Width |
610.0mm (24") |
662.0mm (26.1") |
| Depth |
368.0mm (14.5") |
343.0mm (13.5") |
| Weight |
15.40kg (33.9lbs) |
18.55kg (40.8lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF/Wood veneer |
n/a |
| Available Colors |
Gloss Black, Walnut, and Satin White |
Black, Walnut |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
Yes |
n/a |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |