In this review, we will be comparing Monitor XT35 and Motion 8i, two Passive Center Channel speakers from Polk Audio and MartinLogan. Let's have a brief look at the main features
of Polk XT35 and MartinLogan 8i first before getting into our more
detailed comparison.
What size room are the Polk XT35 and MartinLogan 8i 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 Polk XT35 and MartinLogan 8i 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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Drivers
Both Monitor XT35 and Motion 8i are 2-way speakers.
| Driver |
Polk XT35 |
MartinLogan 8i |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1.0 x 1.4-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
4 x 3-inch
|
2 x 4-inch
|
Monitor XT35 features a 1" Terylene High-res dome Tweeter and 4 x 3" bi-laminate paper cone Woofer . On the other hand, the Motion 8i features a 1.0 x 1.4" Folded Motion Tweeter and 2 x 4" poly cone woofers with rigid dust caps Woofer .
Frequency Response
Monitor XT35 has a frequency range of 57-40k Hz whereas Motion 8i has a frequency range of 70-23k Hz. With a minimum frequency of 57Hz, the Monitor XT35 can go significantly deeper on the low side and provide stronger bass compared to the Motion 8i's min frequency of 70Hz.
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
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
Monitor XT35 is a 8 ohms speaker compared to the Motion 8i 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 Motion 8i can provide this impedance level.
These two speakers also have different sensitivity levels. Monitor XT35 sensitivity is rated at 87 dB and the Motion 8i's is rated at 89 dB. This 2 dB difference makes the MartinLogan 8i a more sensitive speaker compared to Polk XT35, 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.
Monitor XT35 can handle a max power of 200 watts RMS from the amp the whereas Motion 8i has a max power handling value of 180 watts RMS, 20 watts less than the Monitor XT35.
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
Monitor XT35 features Spring post type posts and Motion 8i has a Spring post type posts. None of these speakers feature bi-amping/bi-wiring.
Polk XT35's 5-Way post terminals
MartinLogan 8i's Spring 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 XT35's and MartinLogan 8i's external dimensions. Polk XT35 has external dimensions of 107.0 x 621.0 x 142.0mm ( 4-3/16 x 24-7/16 x 5-9/16inch) whereas MartinLogan 8i has external dimensions of 142.0 x 562.0 x 134.0mm ( 5-9/16 x 22-1/8 x 5-1/4inch) .
MartinLogan 8i is 59mm narrower and 8mm less deeper than Polk XT35 but it is also 35mm taller.
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 XT35 is approximately 881.8cm2 / 136.7inch2 and base area of the MartinLogan 8i is approximately 753.1cm2 / 116.7inch2. The Monitor XT35 requires 17% more surface area than the Motion 8i which gives it a small disadvantage 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 Polk XT35 weighs 6.36kg / 14lbs and the MartinLogan 8i weighs 3.86kg / 8.5lbs. This makes the Monitor XT35 65% heavier than the Motion 8i.
Here is a comparison of how Monitor XT35 and Motion 8i's weights compare with the average, max and min weights in Passive Center Channel class.
Weight
All Center Channel Speakers
What's in the Box of Polk XT35?
Here are the items that are included inside the box of Monitor XT35:
Center-channel loudspeakerGrille (attached)4 Self-adhesive rubber feetOwners ManualOnline Product RegistrationWall-Mount Template
What's in the Box of MartinLogan 8i?
Here are the items that come with the Motion 8i:
LCR loudspeakerGrille2 Wall-bracket2 Shoulder bolts4 Rubber bumpersCleaning clothUser-feets Manual (En/Fr)Installation templateProduct Registration Card
 Max Input Power |
200 watts
vs
180 watts
|
Handle more power from your amplifier |
 Nominal Impedance |
8 ohms
vs
4 ohms
|
Less selective with amplifiers |
 Number of Woofers |
4
vs
2
|
More woofers |
| Low Frequency Response |
57 Hz
vs
70 Hz
|
Generates deeper bass |
 High Frequency Response |
40k Hz
vs
23k Hz
|
Generates higher frequency |
 Height |
107mm
vs
142mm
|
Easier to fit in smaller spaces |
 Price per pair* |
299USD
vs
450USD
|
costs less (*prices may change depending on the seller, location and time) |
 Sensitivity |
89 dB
vs
87 dB
|
Play louder with same amount of amplification power |
| Woofer Size |
4 inches
vs
3 inches
|
Larger woofer |
 Base Surface Area |
753cm2 (562x134mm)
vs
881cm2 (621x142mm)
|
Takes less floor space |
| General |
Polk Audio Monitor XT35 |
MartinLogan Motion 8i |
| Brand |
Polk Audio |
MartinLogan |
| Speaker Type |
Low-profile center channel speaker |
Center channel speaker |
| Power Range |
25-200 watts |
20-180 watts |
| Sensitivity |
87 dB |
89 dB |
| Impedance |
8 ohms |
4 ohms |
| Frequency Response |
57-40k Hz |
70-23k Hz |
Drivers |
|
|
| Woofer Quantity |
4 |
2 |
| Woofer Size |
3" |
4" |
| Woofer Composition |
bi-laminate paper cone |
poly cone woofers with rigid dust caps |
| Tweeter Size |
1" |
1.0 x 1.4" |
| Tweeter Type |
High-res dome |
Folded Motion |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
N/A" |
No |
| Firing Direction |
rear |
n/a |
| Suggested Break-in Period |
n/a |
Allow 72 hours of break-in at 90 dB |
Physical Specs |
|
|
| Height |
107.0mm (4.2") |
142.0mm (5.6") |
| Width |
621.0mm (24.4") |
562.0mm (22.1") |
| Depth |
142.0mm (5.6") |
134.0mm (5.3") |
| Weight |
6.36kg (14lbs) |
3.86kg (8.5lbs) |
| Enclosure |
Bass Reflex |
Passive Radiator |
| Available Colors |
Black |
Gloss Black, Matt White, Red Walnut |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
Other |
|
|
| Parts Warranty |
5 Years |
5 Yrs w/ Registration |
| Labor Warranty |
5 Years |
5 Yrs w/ Registration |