In this review, we will be comparing 255C-RT and RC85i, two Passive In-wall speakers by Polk Audio Let's have a brief look at the main features
of Polk Audio 255C-RT and Polk Audio RC85i first before getting into our more
detailed comparison.
Polk Audio 255C-RT Key Specs
- 2-way Design
- 1" Soft-Dome Tweeter
- 2 x 5.25" Polymer Composite Woofer
- 50-25kHz Frequency Response
- 90 dB Sensitivity
- Impedance: 8ohms
- Power Range:10-150watts
- Dimensions (H x W x D): 193.0" x 13.0625" x 0.0000"
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 Polk Audio 255C-RT 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* |
Polk Audio 255C-RT |
Polk Audio RC85i |
| 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 Polk Audio 255C-RT 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 255C-RT and RC85i are 2-way speakers.
| Driver |
Polk Audio 255C-RT |
Polk Audio RC85i |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
2 x 5.25-inch
|
1 x 8-inch
|
255C-RT features a 1" Soft-Dome Tweeter and 2 x 5.25" Polymer Composite Woofer . On the other hand, the RC85i features a 1" Hard-Dome Tweeter and 1 x 8" Polypropylene Woofer .
Frequency Response
255C-RT has a frequency range of 50-25kHz whereas RC85i has a frequency range of 50-20kHz.
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
255C-RT and RC85i have the same Impedance of 8 ohms and their sensitivity is also same at 90 dB.
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.
255C-RT can handle a max power of 150 watts RMS from the amp the whereas RC85i has a max power handling value of 100 watts RMS, 50 watts less than the 255C-RT.
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
255C-RT 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 Polk Audio 255C-RT's and Polk Audio RC85i's external dimensions. Polk Audio 255C-RT has external dimensions of ( 7.5625-inch x 13.0625-inch x 0.0000-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) .
Polk Audio 255C-RT is 131mm shorter and 89mm less deeper than Polk Audio RC85i but it is also 111mm wider.
What's in the Box of Polk Audio 255C-RT?
Here are the items that are included inside the box of 255C-RT:
In-wall center-channel loudspeakerWhite metal grilleMounting templateOwners ManualSheer-Grille Painting instructionsOnline Registration CardPolk Audio product brochure
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
Max Input Power 
Number of Woofers 
High Frequency Response 
Height 
Base Surface Area 
Price per pair*