In this review, we will be comparing R-51M and LS50, two Passive Bookshelf speakers from Klipsch and KEF. Let's have a brief look at the main features
of Klipsch R-51M and KEF LS50 first before getting into our more
detailed comparison.
What size room are the Klipsch R-51M and KEF LS50 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 Klipsch R-51M 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 R-51M and LS50 are 2-way speakers.
Driver |
Klipsch R-51M |
KEF LS50 |
Driver Setup
|
2-way
|
2-way
|
Tweeter
|
1-inch
|
1-inch
|
Midrange
|
- |
- |
Woofer
|
1 x 5.25-inch
|
1 x 5.25-inch
|
R-51M features a 1" Tractrix Horn Tweeter and 1 x 5.25" Copper-spun IMG Woofer with a Crossover frequency at 1660Hz. 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
R-51M has a frequency range of 62-21k Hz whereas LS50 has a frequency range of 79-28k Hz. With a minimum frequency of 62Hz, the R-51M 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
R-51M and LS50 have the same Impedance of 8 ohms but where they differ is the sensitivity levels. R-51M sensitivity is rated at 93 dB and the LS50's is at 85 dB. This 8 dB difference makes the Klipsch R-51M 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.
R-51M can handle a max power of 100 watts RMS from the amp the whereas R-51M has a max power handling value of 85 watts RMS , 15 watts less than the LS50.
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
R-51M features Post type posts and LS50 has a Post type posts. None of these speakers feature bi-amping/bi-wiring.
Cabinet Type and Port Position
Both R-51M 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 Klipsch R-51M's and KEF LS50's external dimensions. Klipsch R-51M has external dimensions of 338.0 x 178.0 x 215.0mm ( 13.3 x 7.0 x 8.4inch) whereas KEF LS50 has external dimensions of 302.0 x 200.0 x 278.0mm ( 11.8 x 7.8 x 10.9inch) .
Klipsch R-51M is 22mm narrower and 63mm less deeper than KEF LS50 but it is also 36mm taller.
Below you can see the front view size comparison of Klipsch R-51M and KEF LS50 in scale.
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 Klipsch R-51M is approximately 382.7cm2 / 59.3inch2 and base area of the KEF LS50 is approximately 556.0cm2 / 86.2inch2. The R-51M requires 31% 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:
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 Klipsch R-51M weighs 5.00kg / 11lbs and the KEF LS50 weighs 7.20kg / 15.8lbs. This makes the LS50 44% heavier than the R-51M.
Here is a comparison of how R-51M and LS50's weights compare with the average, max and min weights in Passive Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of Klipsch R-51M?
Here are the items that are included inside the box of R-51M:
2 Bookshelf loudspeakers 2 Grilles (installed) 8 Self-adhesive rubber feet Quick Setup Guide Important Safety Instructions Warranty Information
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
Sensitivity |
93 dB
vs
85 dB
|
Play louder with same amount of amplification power |
Low Frequency Response |
62 Hz
vs
79 Hz
|
Generates deeper bass |
Base Surface Area |
382cm2 (178x215mm)
vs
556cm2 (200x278mm)
|
Takes less floor space |
Max Input Power |
100 watts
vs
85 watts
|
Handle more power from your amplifier |
High Frequency Response |
28k Hz
vs
21k Hz
|
Generates higher frequency |
Height |
302mm
vs
338mm
|
Easier to fit in smaller spaces |
General |
Klipsch Reference R-51M |
KEF LS50 |
Brand |
Klipsch |
KEF |
Speaker Type |
Bookshelf speakers |
Bookshelf speakers |
Power Range |
Up to 85 watts |
25-100 watts |
Sensitivity |
93 dB |
85 dB |
Impedance |
8 ohms |
8 ohms |
Impedance |
n/a |
3.2 ohms |
Frequency Response |
62-21k Hz |
79-28k Hz |
Drivers |
|
|
Woofer Quantity |
1 |
1 |
Woofer Size |
5.25" |
5.25" |
Woofer Composition |
Copper-spun IMG |
Magnesium/aluminum alloy |
Woofer Surround Material |
Rubber |
Rubber |
Tweeter Size |
1" |
1" |
Tweeter Type |
Tractrix Horn |
Vented dome |
Aimable Tweeter |
No |
No |
Midrange Driver |
No |
No |
Crossover Frequency |
1660Hz |
2200Hz |
Firing Direction |
rear |
rear |
Physical Specs |
|
|
Height |
338.0mm (13.3") |
302.0mm (11.9") |
Width |
178.0mm (7") |
200.0mm (7.9") |
Depth |
215.0mm (8.5") |
278.0mm (10.9") |
Weight |
5.00kg (11lbs) |
7.20kg (15.8lbs) |
Enclosure |
Bass Reflex |
Bass Reflex |
Finish |
MDF/Wood-grain vinyl |
Polymer/Lacquer |
Available Colors |
Black |
Black, High Gloss Piano Black, High Gloss Piano White |
Mounting Bracket |
No |
No |
Recommended Stand Height |
24-28" |
18-28" |
Grille |
Yes |
n/a |
Moisture Resistancy |
No |
No |
Connections |
|
|
Biamp Inputs |
No |
No |
Other |
|
|
Parts Warranty |
5 Years |
5 Years |
Labor Warranty |
5 Years |
5 Years |