In this review, we will be comparing LSX II and Navis ARB-51, two Powered Bookshelf speakers from KEF and ELAC. Being Powered speakers, they both have built-in amplifiers so you don't need an external power amp or an integrated amp to power them. Let's have a brief look at the main features
of KEF LSX II and ELAC Navis ARB-51 first before getting into our more
detailed comparison.
In the following sections, we will get into more detail in order to better understand how the KEF LSX II and ELAC Navis ARB-51 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
One of the fundamental differences between these two speakers is that LSX II is a 2-way design whereas the Navis ARB-51 is a 3-way speaker. 3-way designs utilize a midrange driver in addition to the tweeter and woofer on 2-way designs. Designing a crossover for a 3-way speaker is a complicated process and generally increases the overall cost of the speaker.
| Driver |
KEF LSX II |
ELAC Navis ARB-51 |
|
Driver Setup
|
2-way
|
3-way
|
|
Tweeter
|
0.75-inch
|
1-inch
|
|
Midrange
|
- |
1 x 4-inch |
|
Woofer
|
1 x 4.5-inch
|
1 x 5.25-inch
|
LSX II features a 0.75" Aluminum Hard-Dome Tweeter and 1 x 4.5" Magnesium/Aluminium alloy Woofer . On the other hand, the Navis ARB-51 features a 1" Fabric Soft-Dome Tweeter , a 4" Midrange and 1 x 5.25" Aluminum Woofer .
Frequency Response
LSX II has a frequency range of 54-28k Hz whereas Navis ARB-51 has a frequency range of 44-28k Hz. With a minimum frequency of 44Hz, the Navis ARB-51 can go significantly deeper on the low side and provide stronger bass compared to the LSX II's min frequency of 54Hz.
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 and Navis ARB-51 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 LSX II's and ELAC Navis ARB-51's external dimensions. KEF LSX II has external dimensions of 240 × 155 × 180 mm ( 9.5 × 6.1 × 7.1 inch) whereas ELAC Navis ARB-51 has external dimensions of 350.8 x 192.1 x 287.3mm ( 13.8125 x 7.5625 x 11.3125inch) .
ELAC Navis ARB-51 is clearly the larger of the two speakers. Its body is 37.1mm wider, 110.8mm taller and 107.3mm deeper than KEF LSX II.
Below you can see the front view size comparison of KEF LSX II and ELAC Navis ARB-51 in scale.
Comparison image of KEF LSX II and ELAC Navis ARB-51 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 is approximately 279.0cm2 / 43.2inch2 and base area of the ELAC Navis ARB-51 is approximately 551.9cm2 / 85.5inch2. The LSX II requires 49% less surface area than the Navis ARB-51 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 and ELAC Navis ARB-51 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 LSX II weighs 3.60kg / 7.9lbs and the ELAC Navis ARB-51 weighs 8.10kg / 17.8lbs. This makes the Navis ARB-51 125% heavier than the LSX II.
Here is a comparison of how LSX II and Navis ARB-51's weights compare with the average, max and min weights in Powered Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of KEF LSX II?
Here are the items that are included inside the box of 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
What's in the Box of ELAC Navis ARB-51?
Here are the items that come with the Navis ARB-51:
2 Powered bookshelf loudspeakersTwo 8-feet AC power cordsOperating Instructions
 Handheld Remote |
Yes
vs
No
|
Control the speaker by the included RC |
 App-Based Control |
Apple iOS, Android
vs
None
|
Control the speaker via an app |
 Height |
240mm
vs
350mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
279cm2 (155x180mm)
vs
551cm2 (192x287mm)
|
Takes less floor space |
 Price per pair* |
1299USD
vs
1998USD
|
costs less (*prices may change depending on the seller, location and time) |
 Ethernet Connection |
Yes
vs
No
|
High quality streaming over Ethernet |
 USB Port |
USB-C (connects to your computer)
vs
No
|
USB port adds flexibility |
 3.5mm Connection |
Yes
vs
No
|
Connection via 3.5mm AUX input |
 Digital Input |
Optical
vs
No
|
Connect digital inputs directly |
 HDMI Input |
ARC
vs
No
|
Connect HDMI sources directly |
 Subwoofer Output |
Wired
vs
No
|
Pair your speakers with external subwoofer |
 Driver Setup |
3-way
vs
2-way
|
Have a dedicated mid-range driver |
 Woofer Size |
5.25 inches
vs
4.5 inches
|
Larger woofer |
| Low Frequency Response |
44 Hz
vs
54 Hz
|
Generates deeper bass |
 RCA Connection |
Yes
vs
No
|
Connection via RCA input |
 XLR Connection |
Yes
vs
No
|
Connection via XLR input |
| General |
KEF LSX II |
ELAC Navis ARB-51 |
| Brand |
KEF |
ELAC |
| Speaker Type |
Powered Stereo Speakers |
Powered Stereo Speakers |
| Frequency Response |
54-28k Hz |
44-28k Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
200-watt RMS |
300-watt RMS |
| Watts Peak (Max) |
n/a |
600-watt RMS |
| Max Bit Depth |
24-bit |
n/a |
| Max Sample Rate |
384 kHz |
n/a |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
4.5" |
5.25" |
| Woofer Composition |
Magnesium/Aluminium alloy |
Aluminum |
| Woofer Surround Material |
Rubber |
n/a |
| Tweeter Size |
0.75" |
1" |
| Tweeter Type |
Hard-Dome |
Soft-Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
4" |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
240.0mm (9.4") |
350.8mm (13.8") |
| Width |
155.0mm (6.1") |
192.1mm (7.6") |
| Depth |
180.0mm (7.1") |
287.3mm (11.3") |
| Weight |
3.60kg (7.9lbs) |
8.10kg (17.8lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Available Colors |
Carbon Black, Mineral White, Cobalt Blue, Lava Red, and Soundwave |
n/a |
| Mounting Bracket |
No |
No |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Aux Inputs |
3.5mm |
XLR, RCA |
| USB Port |
USB-C (connects to your computer) |
No |
| Phone Input |
No |
No |
| Subwoofer Output |
Wired |
No |
| Digital Input |
Optical |
No |
| HDMI Input |
ARC |
No |
| Headphone Jack |
No |
No |
| Ethernet Port |
Yes |
No |
Other |
|
|
| Parts Warranty |
1 Year |
3 Years |
| Labor Warranty |
1 Year |
3 Years |