In this review, we will be comparing LS50 and SX-50, two Passive Bookshelf speakers from KEF and Cambridge Audio. Let's have a brief look at the main features
of KEF LS50 and Cambridge SX-50 first before getting into our more
detailed comparison.
What size room are the KEF LS50 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 KEF LS50 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 LS50 and SX-50 are 2-way speakers.
| Driver |
KEF LS50 |
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
|
LS50 features a 1" Aluminum Vented dome Tweeter and 1 x 5.25" Magnesium/aluminum alloy Woofer with a Crossover frequency at 2200Hz. On the other hand, the SX-50 features a 1" Silk Dome Tweeter and 1 x 5.25" Treated paper Woofer .
Frequency Response
LS50 has a frequency range of 79-28k Hz whereas SX-50 has a frequency range of 50-22k Hz. With a minimum frequency of 50Hz, the SX-50 can go significantly deeper on the low side and provide stronger bass compared to the LS50's min frequency of 79Hz.
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
LS50 and SX-50 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. LS50 sensitivity is rated at 85 dB and the SX-50's is at 90 dB. This 5 dB difference makes the Cambridge SX-50 a more sensitive speaker compared to KEF LS50, 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
LS50 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.
KEF LS50's Post terminals
Cambridge SX-50's 5-way post terminals
Cabinet Type and Port Position
Both LS50 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.
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 KEF LS50's and Cambridge SX-50's external dimensions. KEF LS50 has external dimensions of 302.0 x 200.0 x 278.0mm ( 11.8 x 7.8 x 10.9inch) whereas Cambridge SX-50 has external dimensions of 225.0 x 161.0 x 240.0mm ( 8.8 x 6.3 x 9.4inch) .
KEF LS50 is clearly the larger of the two speakers. Its body is 39mm wider, 77mm taller and 38mm deeper than Cambridge SX-50.
Below you can see the front view size comparison of KEF LS50 and Cambridge SX-50 in scale.
Comparison image of KEF LS50 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 KEF LS50 is approximately 556.0cm2 / 86.2inch2 and base area of the Cambridge SX-50 is approximately 386.4cm2 / 59.9inch2. The LS50 requires 44% more surface area than the SX-50 which gives it a small disadvantage 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 KEF LS50 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 KEF LS50 weighs 7.20kg / 15.8lbs and the Cambridge SX-50 weighs 3.00kg / 6.6lbs. This makes the LS50 140% heavier than the SX-50.
Here is a comparison of how LS50 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 KEF LS50?
Here are the items that are included inside the box of LS50:
2 Bookshelf loudspeakers 2 Foam port plugs 8 Self-adhesive rubber feet Owner's Manual Warranty Registration Card
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 |
28k Hz
vs
22k Hz
|
Generates higher frequency |
 Sensitivity |
90 dB
vs
85 dB
|
Play louder with same amount of amplification power |
 Low Frequency Response |
50 Hz
vs
79 Hz
|
Generates deeper bass |
 Height |
225mm
vs
302mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
386cm2 (161x240mm)
vs
556cm2 (200x278mm)
|
Takes less floor space |
| General |
KEF LS50 |
Cambridge Audio SX-50 |
| Brand |
KEF |
Cambridge Audio |
| Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
| Power Range |
25-100 watts |
10-100 watts |
| Sensitivity |
85 dB |
90 dB |
| Impedance |
8 ohms |
8 ohms |
| Impedance |
3.2 ohms |
n/a |
| Frequency Response |
79-28k Hz |
50-22k Hz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5.25" |
5.25" |
| Woofer Composition |
Magnesium/aluminum alloy |
Treated paper |
| Woofer Surround Material |
Rubber |
Rubber |
| Tweeter Size |
1" |
1" |
| Tweeter Type |
Vented dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
2200Hz |
n/a |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
302.0mm (11.9") |
225.0mm (8.9") |
| Width |
200.0mm (7.9") |
161.0mm (6.3") |
| Depth |
278.0mm (10.9") |
240.0mm (9.4") |
| Weight |
7.20kg (15.8lbs) |
3.00kg (6.6lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Finish |
Polymer/Lacquer |
MDF/Woodgrain vinyl |
| Available Colors |
Black, High Gloss Piano Black, High Gloss Piano White |
Black |
| Mounting Bracket |
No |
No |
| Recommended Stand Height |
18-28" |
28-31" |
| Grille |
n/a |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Biamp Inputs |
No |
No |
Other |
|
|
| Parts Warranty |
5 Years |
5 Years |
| Labor Warranty |
5 Years |
5 Years |