In this review, we will be comparing LSX II LT and LS50, two Bookshelf speakers by KEF The main difference between these two speakers is that the KEF LSX II LT 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 LSX II LT and KEF LS50 first before getting into our more
detailed comparison.
KEF LSX II LT 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 5.0 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 )
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 )
LSX II LT and LS50 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 LSX II LT and KEF LS50 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 LSX II LT and LS50 are 2-way speakers.
| Driver |
KEF LSX II LT |
KEF LS50 |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
0.75-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 4.5-inch
|
1 x 5.25-inch
|
LSX II LT features a 0.75" Aluminum Hard-Dome Tweeter and 1 x 4.5" Magnesium/Aluminium alloy Woofer . On the other hand, the LS50 features a 1" Aluminum Vented dome Tweeter and 1 x 5.25" Magnesium/aluminum alloy Woofer with a Crossover frequency at 2200Hz.
Frequency Response
LSX II LT has a frequency range of 54-28k Hz whereas LS50 has a frequency range of 79-28k Hz. With a minimum frequency of 54Hz, the LSX II LT 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 LSX II LT and LS50 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 KEF LSX II LT's and KEF LS50's external dimensions. KEF LSX II LT has external dimensions of 240 × 155 × 180 mm ( 9.5 × 6.1 × 7.1 inch) whereas KEF LS50 has external dimensions of 302.0 x 200.0 x 278.0mm ( 11.8 x 7.8 x 10.9inch) .
KEF LS50 is clearly the larger of the two speakers. Its body is 45mm wider, 62mm taller and 98mm deeper than KEF LSX II LT.
Below you can see the front view size comparison of KEF LSX II LT and KEF LS50 in scale.
Comparison image of KEF LSX II LT and KEF LS50 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 LSX II LT is approximately 279.0cm2 / 43.2inch2 and base area of the KEF LS50 is approximately 556.0cm2 / 86.2inch2. The LSX II LT requires 50% less surface area than the LS50 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 KEF LSX II LT and KEF LS50 on a Media Console
What's in the Box of KEF LSX II LT?
Here are the items that are included inside the box of LSX II LT:
2 Wireless powered speakers6.5-feet AC power cords3m - 10ft Interspeaker cableRemote control2 AAA batteries Quick Start Guide Important Safety Information Warranty Information Maintenance Guide
What's in the Box of KEF LS50?
Here are the items that come with the LS50:
2 Bookshelf loudspeakers 2 Foam port plugs 8 Self-adhesive rubber feet Owner's Manual Warranty Registration Card
Speaker Type 
Max Input Power 
Low Frequency Response 
Height 
Base Surface Area 
Ethernet Connection