Polk XT15 vs Cambridge SX-50 Comparison

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Polk XT15

Passive Bookshelf | 48-40k Hz

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Cambridge SX-50

Passive Bookshelf | 50-22k Hz

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Polk XT15

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Cambridge SX-50

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Polk XT15

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Cambridge SX-50

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Polk XT15 vs Cambridge SX-50 Speaker Comparison

In this review, we will be comparing XT15 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 XT15 and Cambridge SX-50 first before getting into our more detailed comparison.

Polk XT15 Key Specs

2-way Design

1" Soft-Dome Tweeter

5.25" Bi-laminate paper Woofer

48-40k Hz Frequency Response

86 dB Sensitivity

Impedance: 8ohms

Power Range:30-150watts

Weight:4.09kg

Dimensions (H x W x D): 270.0" x 6-9/16" x 7-3/16"( 270.0 x 167.0 x 183.0mm )

Cambridge SX-50 Key Specs

2-way Design

1" Dome Tweeter

5.25" Treated paper Woofer

50-22k Hz Frequency Response

90 dB Sensitivity

Impedance: 8ohms

Power Range:10-100watts

Weight:3.00kg

Dimensions (H x W x D): 225.0" x 6.3" x 9.4"( 225.0 x 161.0 x 240.0mm )

What size room are the Polk XT15 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:

Listening Environment*	Polk XT15	Cambridge SX-50
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 XT15 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.

**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 XT15 and SX-50 are 2-way speakers.

Driver	Polk XT15	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

XT15 features a 1" Soft-Dome Tweeter and 1 x 5.25" Bi-laminate paper Woofer . On the other hand, the SX-50 features a 1" Silk Dome Tweeter and 1 x 5.25" Treated paper Woofer .

Frequency Response

XT15 has a frequency range of 48-40k Hz whereas SX-50 has a frequency range of 50-22k Hz. With a minimum frequency of 48Hz, the XT15 can go slightly deeper then the SX-50's min frequency of 50Hz.

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

XT15

SX-50

Min

Average

Max

High Frequency

Bookshelf Speakers

Polk XT15

Cambridge SX-50

Min

Average

Max

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

XT15 and SX-50 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. XT15 sensitivity is rated at 86 dB and the SX-50's is at 90 dB. This 4 dB difference makes the Cambridge SX-50 a more sensitive speaker compared to Polk XT15, hence will play louder with the same amount of watts.

Sensitivity

Bookshelf Speakers

XT15

SX-50

Min

Average

Max

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.

XT15 can handle a max power of 150 watts RMS from the amp the whereas SX-50 has a max power handling value of 100 watts RMS, 50 watts less than the XT15.

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

XT15 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.

Cambridge SX-50's 5-way post terminals

Cambridge SX-50 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 Polk XT15's and Cambridge SX-50's external dimensions. Polk XT15 has external dimensions of 270.0 x 167.0 x 183.0mm ( 10-5/8 x 6-9/16 x 7-3/16inch) whereas Cambridge SX-50 has external dimensions of 225.0 x 161.0 x 240.0mm ( 8.8 x 6.3 x 9.4inch) .

Cambridge SX-50 is 6mm narrower and 45mm shorter than Polk XT15 but it is also 57mm deeper.

Below you can see the front view size comparison of Polk XT15 and Cambridge SX-50 in scale.

Comparison image of Polk XT15 and Cambridge SX-50 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 XT15 is approximately 305.6cm² / 47.4inch² and base area of the Cambridge SX-50 is approximately 386.4cm² / 59.9inch². The XT15 requires 21% less surface area than the SX-50 which gives it a small advantage on placement in tight spaces.

Here is an another comparison that shows both speakers on a BDI Octave Media Cabinet, next to a standard size amplifier and turntable in scale:

Size Comparison image of Polk XT15 and Cambridge SX-50 on a Media Console

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 XT15 weighs 4.09kg / 9lbs and the Cambridge SX-50 weighs 3.00kg / 6.6lbs. This makes the XT15 36% heavier than the SX-50.

Here is a comparison of how XT15 and SX-50's weights compare with the average, max and min weights in Passive Bookshelf class.

Weight
All Bookshelf Speakers

Polk XT15

Cambridge SX-50

Min

Average

Max

What's in the Box of Polk XT15?

Here are the items that are included inside the box of XT15:

2 Bookshelf loudspeakers

2 Grilles (attached)

8 Self-adhesive rubber feet

Owners Manual

Online 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

Reasons to choose Polk Audio Monitor XT15 over Cambridge Audio SX-50

Max Input Power	150 watts vs 100 watts	Handle more power from your amplifier
Low Frequency Response	48 Hz vs 50 Hz	Generates deeper bass
High Frequency Response	40k Hz vs 22k Hz	Generates higher frequency
Base Surface Area	305cm² vs 386cm²	Takes less floor space

Reasons to choose Cambridge Audio SX-50 over Polk Audio Monitor XT15

Sensitivity	90 dB vs 86 dB	Play louder with same amount of amplification power
Height	225mm vs 270mm	Easier to fit in smaller spaces

Polk XT15 vs Cambridge SX-50 Specs Table

Detailed comparison of specifications

General	Polk Audio Monitor XT15	Cambridge Audio SX-50
Brand	Polk Audio	Cambridge Audio
Speaker Type	Bookshelf speakers	Bookshelf speakers
Power Range	30-150 watts	10-100 watts
Sensitivity	86 dB	90 dB
Impedance	8 ohms	8 ohms
Frequency Response	48-40k Hz	50-22k Hz
Drivers
Woofer Quantity	1	1
Woofer Size	5.25"	5.25"
Woofer Composition	Bi-laminate paper	Treated paper
Woofer Surround Material	Rubber	Rubber
Tweeter Size	1"	1"
Tweeter Type	Soft-Dome	Dome
Aimable Tweeter	No	No
Midrange Driver	No	No
Firing Direction	n/a	rear
Physical Specs
Height	270.0mm (10.6")	225.0mm (8.9")
Width	167.0mm (6.6")	161.0mm (6.3")
Depth	183.0mm (7.2")	240.0mm (9.4")
Weight	4.09kg (9lbs)	3.00kg (6.6lbs)
Enclosure	Bass Reflex	Bass Reflex
Finish	MDF, Vinyl	MDF/Woodgrain vinyl
Available Colors	Black	Black
Mounting Bracket	No	No
Recommended Stand Height	28-32"	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