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Monitor Audio CS140 vs Polk Audio RC85i Comparison

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Monitor Audio CS140

Passive In-wall | 75-30kHz

Monitor Audio CS140
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Polk Audio RC85i

Passive In-wall | 50-20kHz

Polk Audio RC85i
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Monitor Audio CS140 Monitor Audio CS140
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Polk Audio RC85i Polk Audio RC85i
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Monitor Audio CS140
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Polk Audio RC85i
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Monitor Audio CS140 vs Polk Audio RC85i Speaker Comparison

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.


**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 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

CS140
RC85i
Min
Average
Max
High Frequency

In-wall Speakers

Monitor Audio CS140
Polk Audio RC85i
Min
Average
Max

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

CS140
RC85i
Min
Average
Max

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 speaker
  • Grille
  • Paint skim
  • Installation Guide
  • Important Safety Instructions
  • Cutout Template
  • What's in the Box of Polk Audio RC85i?

    Here are the items that come with the RC85i:
  • 2 White in-wall speakers
  • 2 White grilles
  • 1 Cardboard Mounting Template
  • Owners Manual
  • Online registration sheet
  • Product Registration Card

  • Reasons to choose Monitor Audio CS140 over Polk Audio RC85i
    High Frequency Response 30k Hz vs 20k Hz Generates higher frequency
    Height 150mm vs 324mm Easier to fit in smaller spaces
    Base Surface Area 151cm2 vs 196cm2 Takes less floor space

    Reasons to choose Polk Audio RC85i over Monitor Audio CS140

    Max Input Power 100 watts vs 50 watts Handle more power from your amplifier
    Sensitivity 90 dB vs 85 dB Play louder with same amount of amplification power
    Nominal Impedance 8 ohms vs 6 ohms Less selective with amplifiers
    Woofer Size 8 inches vs 4 inches Larger woofer
    Low Frequency Response 50 Hz vs 75 Hz Generates deeper bass
    Price per pair* 279USD vs 440USD costs less (*prices may change depending on the seller, location and time)
    Monitor Audio CS140 vs Polk Audio RC85i Specs Table
    Detailed comparison of specifications
    General Monitor Audio CS140 Polk Audio RC85i
    Brand Monitor Audio Polk Audio
    Speaker Type Passive In-wall Speaker Passive In-wall Speaker
    Power Range 10-50 watts 20-100 watts
    Sensitivity 85 dB 90 dB
    Impedance 6 ohms 8 ohms
    Frequency Response 75-30kHz 50-20kHz
    Drivers
    Woofer Quantity 1 1
    Woofer Size 4" 8"
    Woofer Composition Metal Matrix Polymer Polypropylene
    Woofer Surround Material Rubber Rubber
    Tweeter Size 1" 1"
    Tweeter Type Hard-Dome Hard-Dome
    Aimable Tweeter Yes Yes
    Midrange Driver N/A" N/A"
    Physical Specs
    Height 150.0mm (5.9") 324.0mm (12.8")
    Width 150.0mm (5.9") 221.0mm (8.7")
    Depth 101.0mm (4") 89.0mm (3.5")
    Enclosure In-wall In-wall
    Moisture Resistancy No Yes
    Connections
    Biamp Inputs No No
    Other
    Parts Warranty Lifetime Lifetime
    Labor Warranty Lifetime Lifetime

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