KEF LS50 is a 2-way Passive Bass Reflex Bookshelf speaker by KEF. It features a 1" Vented dome Tweeter and 1 x 5.25" Magnesium/aluminum alloy Woofer. The speaker has a frequency range of 79-28k Hz and a sensitivity of 85 dB.
Room Size Suitability
The size of the room where you plan to use the KEF LS50 is a crucial factor in your decision. We have assessed its suitability for various room sizes based on its dimensions and maximum power output:
| Listening Environment* |
Suitability |
| Near-field | Average |
| Small Room | Good |
| Mid-size Room | Average |
| Large Room | Poor |
| Very Large Room | 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.)
KEF LS50 Speaker Structure
KEF later replaced LS50 with LS50 Meta. Follow the link to read our in-depth comparison of these speakers:
Compare KEF LS50 vs KEF LS50 Meta
KEF's LS Series of Loudspeakers
LS50 is a member of KEF's LS series of Passive speakers. Below you can see the main specs of these speakers.
**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.
Frequency Response of the KEF LS50 Speaker
KEF LS50 has a Frequency response range of 79-28k Hz at ±3dB and Power Range of 25-100 watts. With a minimum frequency of 79 Hz, it is hard to expect a strong bass response from LS50 so depending on your use case, using a subwoofer will significantly help to widen the response range.
Visit our Powered Subwoofers section to find out more about the available subwoofer options.
Here we have a comparison of how LS50's Low and High frequency values compare with the average, max and min Low and High frequency values in its class.
Low Frequency
Bookshelf Speakers
High Frequency
Bookshelf Speakers
Crossover frequency of the KEF LS50?
The Crossover frequency of the LS50 is set to 2200Hz. This is the threshold frequency where the higher frequency signals over this level are sent to the tweeter and the lower-frequency signals are sent to the woofer by the crossover component.
Impedance and Sensitivity
KEF LS50's nominal impedance level is
8 ohms but can go down to as low as
3.2 ohms, and has a sensitivity of
85 dB.
Sensitivity
Bookshelf Speakers
8 Ohms is pretty much the standard nominal impedance amongst stereo speakers and amplifiers so KEF LS50 is not considered a difficult to drive speaker from nominal Impedance perspective.
Sensitivity
With a sensitivity level of only 85 dB, KEF LS50 is a difficult to drive speaker from Sensitivity perspective, make sure to choose an amplifier with a high output if you like listening to your music at high volume levels. You may especially have a hard time using Tube amplifiers which are traditionally very low power compared to Class A/B or Class D amps.
Minimum Impedance of the KEF LS50
Even though the nominal impedance of the LS50 is 8 ohms, the minimum impedance level of this speaker according to KEF is 3.2 ohms KEF LS50 so while choosing an amplifier, you should ideally check if the unit you are considering can provide this impedance level.
Check the amplifiers that are in a similar price range to the KEF LS50:
Input Type
LS50 features Post type connectors. Bi-amping and Bi-wiring are not possible.
KEF LS50 Back View
KEF LS50 External Dimensions and Weight
KEF LS50 has external dimensions of (Height x Width x Depth) 11.8 x 7.8 x 10.9inch (302.0 x 200.0 x 278.0mm ).
Base Surface Area
Base surface area of a loudspeaker may become a determining factor when the space in your room or desk is limited.
The base area of KEF LS50 is approximately 556.0cm2 / 86.2inch2.
To get a better perspective on the real life size of KEF LS50, let's compare it with a standard size Compact Disc which has a diameter of 4.7inch (120mm).
KEF LS50 Speaker Size Compared to a Compact Disc
Here we place the KEF LS50 virtually next to a standard width amplifier and turntable on a BDI Octave Media Cabinet to get a better idea about the size.
KEF LS50 Speaker next to an amplifier and turntable
WeightThe KEF LS50 weighs 7.20kg / 15.8lbs per piece. Here is a comparison of how LS50's weight compares with the average, max and min weights in its class.
Weight
All Bookshelf Speakers
Cabinet type and Materials
KEF LS50 has a
Bass Reflex type cabinet and a Polymer/Lacquer finish. Bass Reflex type loudspeakers (aka Ported, Vented or Reflex Port) have enclosures that uses a port, hole or vent cut into the cabinet. Ported designs are generally more efficient than the Sealed designs.
Speaker Feet
KEF LS50 comes with
8 Self-adhesive rubber feet which you can use to secure your loudspeaker on the surface that you are putting on. It is always recommended to use some kind of feet under all types of speakers. Besides limiting the movement of the speakers, it also compensates for non-flat surfaces and limits the contact surface area of the speaker. Rubber based feet also help isolating the vibrations within certain frequency ranges.
Port Position
KEF LS50 is a rear-firing port speaker so you have to make sure you leave enough space between the back of the speaker and wall or bookshelf so that it has room to breathe. LS50 comes with
2 Foam port plugs so if you don't have any choice but place the speakers too close to the walls or other surfaces, you can use these plugs in order to avoid boomy or too much bass.
Available colors
KEF LS50 is available in Black, High Gloss Piano Black and High Gloss Piano White.
Wall Mounting
LS50 doesn't sport any built-in mounting bracket, so you need an external structure to mount it on walls.
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
Recommended Accessories
Here is a list of accessories that we think you may need for the KEF LS50.
- Speaker Cable and Connectors
- Vibration Isolators: IsoAcoustics isolators more affordable options too.
- Acoustic Panels and Treatments: Your room is as important as your stereo equipment so acoustic treatments goes a long way in improving the overall performance.
- Speaker Stands: Stands bring your bookshelf speakers to ideal height (rule of thumb is to have the tweeter level with your ear in your listening position), helps stability and acoustical isolation.
User's Manual
For more information about how to setup, use and maintain the KEF LS50, use the direct link below to download the official manual document:
Download User Manual for KEF LS50
Official Brochure
Here is a link to download the official brochure for the KEF LS50 speaker:
Official Brochure for KEF LS50
Official Product Page
Official manufacturer's product page for the KEF LS50 speaker can be found below:
Official Product Page for KEF LS50
Warranty
5 Years of parts warranty and 5 Years of labor warranty is generally provided by the manufacturer.