In this review, we will be comparing 255c-LS and 255C-RT, two Passive In-wall speakers by Polk Audio.
Let's have a brief look at the main features
of Polk Audio 255c-LS and Polk Audio 255C-RT first before getting into our more
detailed comparison.
| Key Specs | Polk Audio 255c-LS | Polk Audio 255C-RT |
|---|
| Brand | Polk Audio
United States · founded 1972 | Polk Audio
United States · founded 1972 |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 1.0" Ring radiator | 1" Soft-Dome |
|---|
| Woofer | 2 x 5.25" Aerated polypropylene | 2 x 5.25" Polymer Composite |
|---|
| Frequency response | 44-29kHz | 50-25kHz |
|---|
| Sensitivity | 91 dB | 90 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 10-150 watts | 10-150 watts |
|---|
| Weight | 3.12kg / 6.9lbs | — |
|---|
| Dimensions (H x W x D) | 7.6250" x 13.1250" x 7-3/8"
194.0 x 334.0 x 187.5mm | 7.5625" x 13.0625" x 3-7/8"
193.0 x 332.0 x 98.4mm |
|---|
What size room are the Polk Audio 255c-LS and Polk Audio 255C-RT 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-LS |
Polk Audio 255C-RT |
| Near-field |
Poor |
Poor |
| Small Room |
Average |
Average |
| Mid-size Room |
Good |
Good |
| Large Room |
Average |
Average |
| Very Large Room |
Poor |
Poor |
(* 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.)
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
Drivers
Both 255c-LS and 255C-RT are 2-way speakers.
Polk Audio 255c-LSPolk Audio 255C-RT
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
Polk Audio 255c-LS |
Polk Audio 255C-RT |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1.0-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
2 x 5.25-inch
|
2 x 5.25-inch
|
255c-LS features a 1.0" Ring radiator Tweeter and 2 x 5.25" Aerated polypropylene Woofer. On the other hand, the 255C-RT features a 1" Soft-Dome Tweeter and 2 x 5.25" Polymer Composite Woofer.
Frequency Response
255c-LS has a frequency range of 44-29kHz whereas 255C-RT has a frequency range of 50-25kHz. With a minimum frequency of 44Hz, the 255c-LS can go significantly deeper on the low side and provide stronger bass compared to the 255C-RT's min frequency of 50Hz.
The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the In-wall class in our database.
Low Frequency
In-wall Speakers
Neither pair reaches down to 20Hz, the usual definition of full-range, which is normal for speakers of this size. If you want the bottom octave for movies or bass-heavy music, add a subwoofer to whichever you choose. Visit our Powered Subwoofers section to find out more about the available options.
Impedance and Sensitivity
255c-LS and 255C-RT have the same Impedance of 8 ohms but where they differ is the sensitivity levels. 255c-LS sensitivity is rated at 91 dB and the 255C-RT's is at 90 dB. This 1 dB difference makes the Polk Audio 255c-LS a more sensitive speaker compared to Polk Audio 255C-RT, 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. Staying
within that range gives nominal performance; driving the speaker beyond its maximum wattage can damage it.
255c-LS and 255C-RT have the same power range of 10-150 watts.
Note that higher power handling does not make a speaker louder: that depends mainly on
sensitivity and impedance. The calculator below shows how loud each of these actually plays
on a real amplifier.
Which plays louder on your amplifier?
Starting with a popular amplifier - change it to the one you own, or any you are
considering, and watch both numbers move.
Input Type and Bi-Amping / Bi-Wiring
255c-LS features Spring post type posts and 255C-RT has a Spring post type posts. None of these speakers feature bi-amping/bi-wiring.
Physical Specs
The size of a speaker can sometimes be 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-LS's and Polk Audio 255C-RT's external dimensions. Polk Audio 255c-LS has external dimensions of 194.0 x 334.0 x 187.5mm (7.6250-inch x 13.1250-inch x 0.0000-inch) whereas Polk Audio 255C-RT has external dimensions of 193.0 x 332.0 x 98.4mm (7.5625-inch x 13.0625-inch x 0.0000-inch).
Polk Audio 255c-LS is clearly the larger of the two speakers. Its body is 2mm wider, 1mm taller and 89.1mm deeper than Polk Audio 255C-RT.
What's in the Box of Polk Audio 255c-LS?
Here are the items that are included inside the box of 255c-LS:
- In-wall loudspeaker
- White metal grille
- Mounting template
- Owners Manual
What's in the Box of Polk Audio 255C-RT?
Here are the items that come with the 255C-RT:
- In-wall center-channel loudspeaker
- White metal grille
- Mounting template
- Owners Manual
- Sheer-Grille Painting instructions
- Online Registration Card
- Polk Audio product brochure