In this review, we will be comparing S15 and SX-50, two Passive Bookshelf speakers from Polk Audio and Cambridge Audio. Let's have a brief look at the main features
of Polk S15 and Cambridge SX-50 first before getting into our more
detailed comparison.
What size room are the Polk S15 and Cambridge SX-50 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:
In the following sections, we will get into more detail in order to better understand how the Polk S15 and Cambridge SX-50 compare and hopefully end up with enough arguments to decide which one of these loudspeakers is the better choice for you.
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Drivers
Both S15 and SX-50 are 2-way speakers.
Driver |
Polk S15 |
Cambridge SX-50 |
Driver Setup
|
2-way
|
2-way
|
Tweeter
|
1-inch
|
1-inch
|
Midrange
|
- |
- |
Woofer
|
1 x 5.25-inch
|
1 x 5.25-inch
|
S15 features a 1" Terylene Dome Tweeter and 1 x 5.25" Mica-reinforced polypropylene Woofer with a Crossover frequency at 2500Hz. On the other hand, the SX-50 features a 1" Silk Dome Tweeter and 1 x 5.25" Treated paper Woofer .
Frequency Response
S15 has a frequency range of 50-40k Hz whereas SX-50 has a frequency range of 50-22k Hz.
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 Bookshelf class in our database.
Low Frequency
Bookshelf Speakers
High Frequency
Bookshelf 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
S15 and SX-50 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. S15 sensitivity is rated at 88 dB and the SX-50's is at 90 dB. This 2 dB difference makes the Cambridge SX-50 a more sensitive speaker compared to Polk S15, hence will play louder with the same amount of watts.
Sensitivity
Bookshelf 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.
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
S15 features 5-way post type posts and SX-50 has a 5-way post type posts. None of these speakers feature bi-amping/bi-wiring.
Cabinet Type and Port Position
Both S15 and SX-50 have rear firing ports. Rear ported speakers generally need more room between the backside of the speaker and the wall compared to sealed and front/bottom ported speakers. Placing the speakers too close to the walls may cause the bass to sound boomy.
If you are limited in space and can't get the speakers away from the backwall, check our Speakers with Front Firing Ports page.
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 S15's and Cambridge SX-50's external dimensions. Polk S15 has external dimensions of 304.8 x 190.0 x 260.4mm ( 12.0 x 7.4 x 10.2inch) whereas Cambridge SX-50 has external dimensions of 225.0 x 161.0 x 240.0mm ( 8.8 x 6.3 x 9.4inch) .
Polk S15 is clearly the larger of the two speakers. Its body is 29mm wider, 79.8mm taller and 20.4mm deeper than Cambridge SX-50.
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 S15 is approximately 494.8cm2 / 76.7inch2 and base area of the Cambridge SX-50 is approximately 386.4cm2 / 59.9inch2. The S15 requires 28% more surface area than the SX-50 which gives it a small disadvantage 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 S15 weighs 5.90kg / 13lbs and the Cambridge SX-50 weighs 3.00kg / 6.6lbs. This makes the S15 97% heavier than the SX-50.
Here is a comparison of how S15 and SX-50's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of Polk S15?
Here are the items that are included inside the box of S15:
2 Bookshelf loudspeakers2 Grille (attached)8 Self-adhesive rubber feetWall-mount templateOwners ManualOnline Product Registration
What's in the Box of Cambridge SX-50?
Here are the items that come with the SX-50:
2 Bookshelf loudspeakers 2 Grilles 8 Self-adhesive feet 2 Foam port inserts Installation Guide
High Frequency Response |
40k Hz
vs
22k Hz
|
Generates higher frequency |
Mounting Bracket |
Yes
vs
No
|
Allows mounting on walls |
Sensitivity |
90 dB
vs
88 dB
|
Play louder with same amount of amplification power |
Height |
225mm
vs
304mm
|
Easier to fit in smaller spaces |
Base Surface Area |
386cm2 (161x240mm)
vs
494cm2 (190x260mm)
|
Takes less floor space |
Price per pair* |
199USD
vs
259USD
|
costs less (*prices may change depending on the seller, location and time) |
General |
Polk Audio Signature S15 |
Cambridge Audio SX-50 |
Brand |
Polk Audio |
Cambridge Audio |
Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
Power Range |
20-100 watts |
10-100 watts |
Sensitivity |
88 dB |
90 dB |
Impedance |
8 ohms |
8 ohms |
Frequency Response |
50-40k Hz |
50-22k Hz |
Drivers |
|
|
Woofer Quantity |
1 |
1 |
Woofer Size |
5.25" |
5.25" |
Woofer Composition |
Mica-reinforced polypropylene |
Treated paper |
Woofer Surround Material |
Butyl rubber |
Rubber |
Tweeter Size |
1" |
1" |
Tweeter Type |
Dome |
Dome |
Aimable Tweeter |
No |
No |
Midrange Driver |
No |
No |
Crossover Frequency |
2500Hz |
n/a |
Firing Direction |
rear |
rear |
Physical Specs |
|
|
Height |
304.8mm (12") |
225.0mm (8.9") |
Width |
190.0mm (7.5") |
161.0mm (6.3") |
Depth |
260.4mm (10.3") |
240.0mm (9.4") |
Weight |
5.90kg (13lbs) |
3.00kg (6.6lbs) |
Enclosure |
Bass Reflex |
Bass Reflex |
Finish |
Meddite MDF |
MDF/Woodgrain vinyl |
Available Colors |
Black, Walnut, Brown Walnut |
Black |
Mounting Bracket |
Keyhole |
No |
Recommended Stand Height |
24-30" |
28-31" |
Grille |
Yes |
Yes |
Moisture Resistancy |
No |
No |
Connections |
|
|
Biamp Inputs |
No |
No |
Other |
|
|
Parts Warranty |
5 Years |
5 Years |
Labor Warranty |
5 Years |
5 Years |