In this review, we will be comparing CS140 and RC85i, two Passive In-wall speakers from Monitor Audio and Polk Audio. Let's have a brief look at the main features
of Monitor Audio CS140 and Polk Audio RC85i first before getting into our more
detailed comparison.
Monitor Audio CS140 Key Specs
- 2-way Design
- 1" Hard-Dome Tweeter
- 4" Metal Matrix Polymer Woofer
- 75-30kHz Frequency Response
- 85 dB Sensitivity
- Impedance: 6ohms
- Power Range:10-50watts
- Dimensions (H x W x D): 150.0" x 5.8750" x 3.9375"( 150.0 x 150.0 x 101.0mm )
Polk Audio RC85i Key Specs
- 2-way Design
- 1" Hard-Dome Tweeter
- 8" Polypropylene Woofer
- 50-20kHz Frequency Response
- 90 dB Sensitivity
- Impedance: 8ohms
- Power Range:20-100watts
- Dimensions (H x W x D): 324.0" x 8.6875" x 3.5000"( 324.0 x 221.0 x 89.0mm )
What size room are the Monitor Audio CS140 and Polk Audio RC85i 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* |
Monitor Audio CS140 |
Polk Audio RC85i |
| Near-field |
Good |
Average |
| Small Room |
Good |
Good |
| Mid-size Room |
Average |
Average |
| Large Room |
Poor |
Poor |
| Very Large Room |
No way |
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 Monitor Audio CS140 and Polk Audio RC85i 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 CS140 and RC85i are 2-way speakers.
| Driver |
Monitor Audio CS140 |
Polk Audio RC85i |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 4-inch
|
1 x 8-inch
|
CS140 features a 1" Hard-Dome Tweeter and 1 x 4" Metal Matrix Polymer Woofer . On the other hand, the RC85i features a 1" Hard-Dome Tweeter and 1 x 8" Polypropylene Woofer .
Frequency Response
CS140 has a frequency range of 75-30kHz whereas RC85i has a frequency range of 50-20kHz. With a minimum frequency of 50Hz, the RC85i can go significantly deeper on the low side and provide stronger bass compared to the CS140's min frequency of 75Hz.
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
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
CS140 is a 6 ohms speaker compared to the RC85i which has a nominal impedance of 8 ohms.
These two speakers also have different sensitivity levels. CS140 sensitivity is rated at 85 dB and the RC85i's is rated at 90 dB. This 5 dB difference makes the Polk Audio RC85i a more sensitive speaker compared to Monitor Audio CS140, 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.
CS140 can handle a max power of 100 watts RMS from the amp the whereas CS140 has a max power handling value of 50 watts RMS , 50 watts less than the RC85i.
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
CS140 features Spring clip type posts and RC85i has a Spring clip 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 Monitor Audio CS140's and Polk Audio RC85i's external dimensions. Monitor Audio CS140 has external dimensions of 150.0 x 150.0 x 101.0mm ( 5.8750-inch x 5.8750-inch x 3.9375-inch) whereas Polk Audio RC85i has external dimensions of 324.0 x 221.0 x 89.0mm ( 12.7500-inch x 8.6875-inch x 3.5000-inch) .
Monitor Audio CS140 is 71mm narrower and 174mm shorter than Polk Audio RC85i but it is also 12mm deeper.
What's in the Box of Monitor Audio CS140?
Here are the items that are included inside the box of CS140:
In-ceiling speakerGrillePaint skimInstallation GuideImportant Safety InstructionsCutout Template
What's in the Box of Polk Audio RC85i?
Here are the items that come with the RC85i:
2 White in-wall speakers2 White grilles1 Cardboard Mounting TemplateOwners ManualOnline registration sheetProduct Registration Card
High Frequency Response 
Height 
Base Surface Area 
Max Input Power 
Sensitivity 
Nominal Impedance 
Woofer Size 
Price per pair*