In this review, we will be comparing UIW RSS III and Motion CI MW4-LCR, two Passive In-wall speakers from Definitive Technology and MartinLogan. Let's have a brief look at the main features
of Definitive UIW RSS III and MartinLogan Motion CI MW4-LCR first before getting into our more
detailed comparison.
Definitive UIW RSS III Key Specs
- 2-way Design
- 1" Hard-Dome Tweeter
- 2 x 3.5" Polypropylene Woofer
- 40-30kHz Frequency Response
- 90 dB Sensitivity
- Impedance: 8ohms
- Power Range:10-200watts
- Dimensions (H x W x D): 251.0" x 8.3750" x 3.8750"( 251.0 x 213.0 x 99.0mm )
MartinLogan Motion CI MW4-LCR Key Specs
- 2-way Design
- 1" Folded Motion Ribbon Tweeter
- 2 x 4" Fiberglass Woofer
- 78-25kHz Frequency Response
- 93 dB Sensitivity
- Impedance: 8ohms
- Power Range:50-100watts
- Dimensions (H x W x D): 134.0" x 11.8750" x 2.6875"( 134.0 x 302.0 x 69.0mm )
What size room are the Definitive UIW RSS III and MartinLogan Motion CI MW4-LCR 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* |
Definitive UIW RSS III |
MartinLogan Motion CI MW4-LCR |
| Near-field |
Poor |
Average |
| Small Room |
Average |
Good |
| Mid-size Room |
Good |
Average |
| Large Room |
Average |
Poor |
| Very Large Room |
Poor |
Bad |
(* 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 Definitive UIW RSS III and MartinLogan Motion CI MW4-LCR 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 UIW RSS III and Motion CI MW4-LCR are 2-way speakers.
| Driver |
Definitive UIW RSS III |
MartinLogan Motion CI MW4-LCR |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
2 x 3.5-inch
|
2 x 4-inch
|
UIW RSS III features a 1" Hard-Dome Tweeter and 2 x 3.5" Polypropylene Woofer . On the other hand, the Motion CI MW4-LCR features a 1" Folded Motion Ribbon Tweeter and 2 x 4" Fiberglass Woofer .
Frequency Response
UIW RSS III has a frequency range of 40-30kHz whereas Motion CI MW4-LCR has a frequency range of 78-25kHz. With a minimum frequency of 40Hz, the UIW RSS III can go significantly deeper on the low side and provide stronger bass compared to the Motion CI MW4-LCR's min frequency of 78Hz.
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 In-wall class in our database.
Low Frequency
In-wall Speakers
High Frequency
In-wall Speakers
MartinLogan Motion CI MW4-LCR
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
UIW RSS III and Motion CI MW4-LCR have the same Impedance of 8 ohms but where they differ is the sensitivity levels. UIW RSS III sensitivity is rated at 90 dB and the Motion CI MW4-LCR's is at 93 dB. This 3 dB difference makes the MartinLogan Motion CI MW4-LCR a more sensitive speaker compared to Definitive UIW RSS III, hence will play louder with the same amount of watts.
Sensitivity
In-wall 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.
UIW RSS III can handle a max power of 200 watts RMS from the amp the whereas Motion CI MW4-LCR has a max power handling value of 100 watts RMS, 100 watts less than the UIW RSS III.
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
UIW RSS III features Spring post type posts and Motion CI MW4-LCR has a Spring post type posts. None of these speakers feature bi-amping/bi-wiring.
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 Definitive UIW RSS III's and MartinLogan Motion CI MW4-LCR's external dimensions. Definitive UIW RSS III has external dimensions of 251.0 x 213.0 x 99.0mm ( 9.8750-inch x 8.3750-inch x 3.8750-inch) whereas MartinLogan Motion CI MW4-LCR has external dimensions of 134.0 x 302.0 x 69.0mm ( 5.2500-inch x 11.8750-inch x 2.6875-inch) .
MartinLogan Motion CI MW4-LCR is 117mm shorter and 30mm less deeper than Definitive UIW RSS III but it is also 89mm wider.
What's in the Box of Definitive UIW RSS III?
Here are the items that are included inside the box of UIW RSS III:
In-wall/In-cieling bipolar speakerGrille7 Foam strips2 ScrewsPaint maskWall templateOwners ManualOnline Product Registration Card
What's in the Box of MartinLogan Motion CI MW4-LCR?
Here are the items that come with the Motion CI MW4-LCR:
In-wall loudspeakerGrilleTorx-bitUser-feets ManualCutout Template
Max Input Power 
Low Frequency Response 
High Frequency Response 
Passive Radiator 
Price per pair* 
Sensitivity 
Height 
Base Surface Area