In this review, we will be comparing LS50 and LSX II, two Bookshelf speakers by KEF The main difference between these two speakers is that the KEF LSX II is a Powered speaker which means that it has a built-in amplifier inside the speaker body so you don't need an external power amp or an integrated amp whereas the KEF LS50 is a Passive speaker so has to be matched with an amplifier to get any sound from it. Let's have a brief look at the main features
of KEF LS50 and KEF LSX II first before getting into our more
detailed comparison.
KEF LS50 Key Specs
- 2-way Design
- 11th Generation Uni-Q Driver
- 1" Vented dome Tweeter
- 5.25" Magnesium/aluminum alloy Woofer
- 79-28k Hz Frequency Response
- 85 dB Sensitivity
- Impedance: 8ohms
- Power Range:25-100watts
- Weight:7.20kg
- Dimensions (H x W x D): 302.0" x 7.8" x 10.9"( 302.0 x 200.0 x 278.0mm )
KEF LSX II Key Specs
- 2-way Design
- 200-watt RMS Integrated Amplifier
- 11th Generation Uni-Q Driver
- 0.75" Hard-Dome Tweeter
- 4.5" Magnesium/Aluminium alloy Woofer
- 54-28k Hz Frequency Response
- 24-bit Max Depth / 384 kHz Max Sample Rate
- Built-in 4.2 Bluetooth
- App Control Feature
- Weight:3.60kg
- Dimensions (H x W x D): 240.0" x 6.1" x 7.1"( 240 × 155 × 180 mm )
LS50 and LSX II are members of KEF's LS series of speakers. Below you can find the loudspeakers from this series.
In the following sections, we will get into more detail in order to better understand how the KEF LS50 and KEF LSX II 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 LS50 and LSX II are 2-way speakers.
| Driver |
KEF LS50 |
KEF LSX II |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1-inch
|
0.75-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5.25-inch
|
1 x 4.5-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 LSX II features a 0.75" Aluminum Hard-Dome Tweeter and 1 x 4.5" Magnesium/Aluminium alloy Woofer .
Frequency Response
LS50 has a frequency range of 79-28k Hz whereas LSX II has a frequency range of 54-28k Hz. With a minimum frequency of 54Hz, the LSX II 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.
Cabinet Type and Port Position
Both LS50 and LSX II 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.
KEF LSX II 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 KEF LSX II'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 KEF LSX II has external dimensions of 240 × 155 × 180 mm ( 9.5 × 6.1 × 7.1 inch) .
KEF LS50 is clearly the larger of the two speakers. Its body is 45mm wider, 62mm taller and 98mm deeper than KEF LSX II.
Below you can see the front view size comparison of KEF LS50 and KEF LSX II in scale.
Comparison image of KEF LS50 and KEF LSX II 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 KEF LSX II is approximately 279.0cm2 / 43.2inch2. The LS50 requires 99% more surface area than the LSX II 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 KEF LSX II on a Media Console
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 KEF LSX II?
Here are the items that come with the LSX II:
2 Wireless powered speakersTwo 6.5-feet AC power cords10-feet Cat-6 interconnect speaker cableRemote control2 AAA batteries Quick Start Guide Important Safety Information Warranty Information Maintenance Guide
Woofer Size 
Speaker Type 
Max Input Power 
Height 
Base Surface Area 
Ethernet Connection 
3.5mm Connection