In this review, we will be comparing R7 and S55, two Passive Floor-standing speakers from KEF and Polk Audio.
Let's have a brief look at the main features
of KEF R7 and Polk S55 first before getting into our more
detailed comparison.
KEF R7 Key Specs
- 3-way Design
- 1" Dome Tweeter
- 5" Midrange
- 2 x 6.5" Hybrid Aluminum Woofer
- 48-28k Hz Frequency Response
- 88 dB Sensitivity
- Impedance: 8ohms
- Power Range:15-250watts
- Weight:31.40kg
- Dimensions (H x W x D): 1113.0" x 8" x 15-5/16"( 1113.0 x 200.0 x 389.0mm )
Polk S55 Key Specs
- 2-way Design
- 1" Dome Tweeter
- 2 x 6.5" Mica-reinforced polypropylene Woofer
- 32-40k Hz Frequency Response
- 90 dB Sensitivity
- Impedance: 8ohms
- Power Range:20-200watts
- Weight:20.00kg
- Dimensions (H x W x D): 1056.0" x 11-3/4" x 12-3/8"( 1056.0 x 299.0 x 315.0mm )
What size room are the KEF R7 and Polk S55 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* |
KEF R7 |
Polk S55 |
| Near-field |
Bad |
Bad |
| Small Room |
Poor |
Poor |
| Mid-size Room |
Average |
Good |
| Large Room |
Good |
Good |
| Very Large Room |
Average |
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.)
In the following sections, we will get into more detail in order to better understand how the KEF R7 and Polk S55 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
One of the fundamental differences between these two speakers is that R7 is a 3-way design whereas the S55 is a 2-way speaker. 3-way designs utilize a midrange driver in addition to the tweeter and woofer on 2-way designs. Designing a crossover for a 3-way speaker is a complicated process and generally increases the overall cost of the speaker.
| Driver |
KEF R7 |
Polk S55 |
|
Driver Setup
|
3-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
1 x 5-inch |
- |
|
Woofer
|
2 x 6.5-inch
|
2 x 6.5-inch
|
R7 features a 1" aluminum Dome Tweeter , a 5" Midrange and 2 x 6.5" Hybrid Aluminum Woofer with a Crossover frequency at 400Hz and 2900Hz. On the other hand, the S55 features a 1" Terylene Dome Tweeter and 2 x 6.5" Mica-reinforced polypropylene Woofer with a Crossover frequency at 2500Hz.
Frequency Response
R7 has a frequency range of 48-28k Hz whereas S55 has a frequency range of 32-40k Hz. With a minimum frequency of 32Hz, the S55 can go significantly deeper on the low side and provide stronger bass compared to the R7's min frequency of 48Hz.
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 Floor-standing class in our database.
Low Frequency
Floor-standing Speakers
High Frequency
Floor-standing 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
R7 and S55 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. R7 sensitivity is rated at 88 dB and the S55's is at 90 dB. This 2 dB difference makes the Polk S55 a more sensitive speaker compared to KEF R7, hence will play louder with the same amount of watts.
Sensitivity
Floor-standing 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.
R7 can handle a max power of 250 watts RMS from the amp the whereas S55 has a max power handling value of 200 watts RMS, 50 watts less than the R7.
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
Both R7 and S55 features dual binding post speaker terminals for bi-amping or bi-wiring.
KEF R7's Binding post terminals allows Bi-amping or bi-wiring
Polk S55's 5-way post terminals allows Bi-amping or bi-wiring
Cabinet Type and Port Position
R7 has a rear firing port whereas S55 has a bottom firing ports. Polk S55's bottom-firing port gives more flexibility in placement in regards to proximity to walls compared to KEF R7 with its rear-firing port.
Polk S55 Port
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 KEF R7's and Polk S55's external dimensions. KEF R7 has external dimensions of 1113.0 x 200.0 x 389.0mm ( 43-13/16 x 8 x 15-5/16inch) whereas Polk S55 has external dimensions of 1056.0 x 299.0 x 315.0mm ( 41-9/16 x 11-3/4 x 12-3/8inch) .
Polk S55 is 57mm shorter and 74mm less deeper than KEF R7 but it is also 99mm wider.
Base Surface Area Comparison
Base surface area of a loudspeaker may become a determining factor when the space in your room or desk is limited.
The base surface area of the KEF R7 is approximately 778.0cm2 / 120.6inch2 and base area of the Polk S55 is approximately 941.9cm2 / 146.0inch2. The R7 requires 17% less surface area than the S55 which gives it a small advantage on placement in tight spaces.
Weight Comparison The weight of a loudspeaker can become an important factor if you need to move and reposition the unit often. Weight of a speaker can also "sometimes" be an indicator of the rigidity of the enclosure and the quality of the internal components used. The KEF R7 weighs 31.40kg / 69.1lbs and the Polk S55 weighs 20.00kg / 44lbs. This makes the R7 57% heavier than the S55.
Here is a comparison of how R7 and S55's weights compare with the average, max and min weights in Passive Floor-standing class.
Weight
All Floor-standing Speakers
What's in the Box of KEF R7?
Here are the items that are included inside the box of R7:
Floorstanding loudspeakerGrille2 Foam port plugs4 Outrigger feet4 Spikes4 Protective discs4 Screws4 WashersWrenchHex-keyUser ManualWarranty Information
What's in the Box of Polk S55?
Here are the items that come with the S55:
Floorstanding loudspeakerGrille (attached)4 Feet (pre-installed)Owners ManualOnline Product Registration
 Max Input Power |
250 watts
vs
200 watts
|
Handle more power from your amplifier |
 Driver Setup |
3-way
vs
2-way
|
Have a dedicated mid-range driver |
 Base Surface Area |
778cm2
vs
941cm2
|
Takes less floor space |
 Sensitivity |
90 dB
vs
88 dB
|
Play louder with same amount of amplification power |
 Low Frequency Response |
32 Hz
vs
48 Hz
|
Generates deeper bass |
 High Frequency Response |
40k Hz
vs
28k Hz
|
Generates higher frequency |
 Height |
1056mm
vs
1113mm
|
Easier to fit in smaller spaces |
 Price per pair* |
658USD
vs
4500USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
KEF R7 |
Polk Audio Signature S55 |
| Brand |
KEF |
Polk Audio |
| Speaker Type |
Floor-standing speaker |
Floor-standing speaker |
| Power Range |
15-250 watts |
20-200 watts |
| Sensitivity |
88 dB |
90 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
3.2 ohms |
n/a |
| Frequency Response |
48-28k Hz |
32-40k Hz |
Drivers |
|
|
| Woofer Quantity |
2 |
2 |
| Woofer Size |
6.5" |
6.5" |
| Woofer Composition |
Hybrid Aluminum |
Mica-reinforced polypropylene |
| Woofer Surround Material |
Rubber |
Butyl rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
5" |
No |
| Crossover Frequency |
400Hz and 2900Hz |
2500Hz |
| Firing Direction |
rear |
bottom |
Physical Specs |
|
|
| Height |
1113.0mm (43.8") |
1056.0mm (41.6") |
| Width |
200.0mm (7.9") |
299.0mm (11.8") |
| Depth |
389.0mm (15.3") |
315.0mm (12.4") |
| Weight |
31.40kg (69.1lbs) |
20.00kg (44lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
MDF/Lacquer |
Meddite MDF |
| Available Colors |
Black Gloss, White Gloss, Walnut |
Black |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
Yes |
Yes |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |