In this review, we will be comparing XT70 and S55, two Passive Floor-standing speakers by Polk Audio.
Let's have a brief look at the main features
of Polk XT70 and Polk S55 first before getting into our more
detailed comparison.
| Key Specs | Polk XT70 | Polk S55 |
|---|
| Brand | Polk Audio
United States · founded 1972 | Polk Audio
United States · founded 1972 |
|---|
| Design | 2-way | 2-way |
|---|
| Tweeter | 1" dome | 1" Dome |
|---|
| Woofer | 2 x 6.5" Bi-laminate paper | 2 x 6.5" Mica-reinforced polypropylene |
|---|
| Frequency response | 35-40k Hz | 32-40k Hz |
|---|
| Sensitivity | 86 dB | 90 dB |
|---|
| Impedance | 8 ohms | 8 ohms |
|---|
| Power range | 25-200 watts | 20-200 watts |
|---|
| Weight | 15.91kg / 35lbs | 20.00kg / 44lbs |
|---|
| Dimensions (H x W x D) | 40-9/16" x 10-13/16" x 13-3/8"
1031.0 x 275.0 x 340.0mm | 41-9/16" x 11-3/4" x 12-3/8"
1056.0 x 299.0 x 315.0mm |
|---|
What size room are the Polk XT70 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* |
Polk XT70 |
Polk S55 |
| Near-field |
Bad |
Bad |
| Small Room |
Poor |
Poor |
| Mid-size Room |
Good |
Good |
| Large Room |
Good |
Good |
| 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 XT70 and S55 are 2-way speakers.
Polk XT70Polk S55
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 XT70 |
Polk S55 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
2 x 6.5-inch
|
2 x 6.5-inch
|
XT70 features a 1" Terylene dome Tweeter and 2 x 6.5" Bi-laminate paper Woofer. 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
XT70 has a frequency range of 35-40k Hz whereas S55 has a frequency range of 32-40k Hz. With a minimum frequency of 32Hz, the S55 can go slightly deeper then the XT70's min frequency of 35Hz.
The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the Floor-standing class in our database.
Low Frequency
Floor-standing 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
XT70 and S55 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. XT70 sensitivity is rated at 86 dB and the S55's is at 90 dB. This 4 dB difference makes the Polk S55 a more sensitive speaker compared to Polk XT70, 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. Staying
within that range gives nominal performance; driving the speaker beyond its maximum wattage can damage it.
Both handle the same maximum of 200 watts RMS, though XT70 is rated 25-200 watts and S55 20-200 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
S55 features 5-way post posts which make bi-amping or bi-wiring possible. XT70 has a 5-Way post which doesn't feature bi-amping/bi-wiring.
Polk S55's 5-way post terminals allows Bi-amping or bi-wiring
Polk S55 Port
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 XT70's and Polk S55's external dimensions. Polk XT70 has external dimensions of 1031.0 x 275.0 x 340.0mm (40-9/16 x 10-13/16 x 13-3/8inch) 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 XT70 is 24mm narrower and 25mm shorter than Polk S55 but it is also 25mm deeper.
Below you can see the front view size comparison of Polk XT70 and Polk S55 in scale.
Comparison image of Polk XT70 and Polk S55 Size and External Dimensions
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 Polk XT70 is approximately 935.0cm2 / 144.9inch2 and base area of the Polk S55 is approximately 941.9cm2 / 146.0inch2. The XT70 requires 1% 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 Polk XT70 weighs 15.91kg / 35lbs and the Polk S55 weighs 20.00kg / 44lbs. This makes the S55 26% heavier than the XT70.
Here is a comparison of how XT70 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 Polk XT70?
Here are the items that are included inside the box of XT70:
- Floorstanding loudspeaker
- Grille (attached)
- Owners Manual
- Online Product Registration
What's in the Box of Polk S55?
Here are the items that come with the S55:
- Floorstanding loudspeaker
- Grille (attached)
- 4 Feet (pre-installed)
- Owners Manual
- Online Product Registration
 Passive Radiator |
two 8-inch
vs
None
|
Increases the bass performance |
 Dolby Atmos Drivers |
Optional
vs
No
|
Dolby Atmos Compatibility |
 Height |
1031mm
vs
1056mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
935cm2
vs
941cm2
|
Takes less floor space |
 Sensitivity |
90 dB
vs
86 dB
|
Play louder with same amount of amplification power |
 Low Frequency Response |
32 Hz
vs
35 Hz
|
Generates deeper bass |
 Bi-Amping and Bi-Wiring |
Yes
vs
No
|
Allows bi-amping and bi-wiring connections |
 Price per pair* |
658USD
vs
698USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Polk Audio Monitor XT70 |
Polk Audio Signature S55 |
| Brand |
Polk Audio |
Polk Audio |
| Speaker Type |
Floor-standing speaker |
Floor-standing speaker |
| Power Range |
25-200 watts |
20-200 watts |
| Sensitivity |
86 dB |
90 dB |
| Impedance |
8 ohms |
8 ohms |
| Frequency Response |
35-40k Hz |
32-40k Hz |
Drivers |
|
|
| Woofer Quantity |
2 |
2 |
| Woofer Size |
6.5" |
6.5" |
| Woofer Composition |
Bi-laminate paper |
Mica-reinforced polypropylene |
| Woofer Surround Material |
Rubber |
Butyl rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
2500Hz |
| Firing Direction |
n/a |
bottom |
Physical Specs |
|
|
| Height |
1031.0mm (40.6") |
1056.0mm (41.6") |
| Width |
275.0mm (10.8") |
299.0mm (11.8") |
| Depth |
340.0mm (13.4") |
315.0mm (12.4") |
| Weight |
15.91kg (35lbs) |
20.00kg (44lbs) |
| Enclosure |
Passive Radiator |
Bass Reflex |
| Finish |
MDF, Vinyl |
Meddite MDF |
| Available Colors |
Black |
Black |
| Grille |
Yes |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
Yes |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |
A generation apart: Polk XT70 is the newer design, against a 2016 model. Newer is not automatically better, but the older one is more likely to be discounted or near run-out.
| Area | Better | Why |
|---|
| Bass | B | Polk S55 digs deeper - 32Hz against 35Hz. A subwoofer would even that out. |
| Amplifier needs | B | Polk S55 is more sensitive (90dB vs 86dB), so it goes louder on the same amplifier. |
| Headroom | evenly matched | Similar power handling (200W vs 200W). |
| Size | depends | Similar cabinet size - neither is easier to fit. |
| Cabinet | depends | Passive Radiator vs Ported. |
| Expandability | depends | Polk XT70: Atmos drivers; Polk S55: bi-amping. Polk XT70 sits in a wider range (9 models), so a matched surround system is easier later. |
| Price | evenly matched | Much the same money ($698 vs $658 a pair). |
A Polk XT70 B Polk S55
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both speakers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
Polk S55 has the edge on paper, though the margin is not large. The rows marked "depends" may matter more to you than the score does. If your amplifier is modest, vintage or valve-based, Polk S55 is the safer partner - the other will want more current or more watts to sound its best.
And remember what a spec sheet cannot show: how each looks in your room and whether the finish suits it, what dealer support and warranty are like where you live, and how they actually sound to you. If you can hear them first - ideally with your own music - that will tell you more than any number above.