In this review, we will be comparing LSX II and M20 HD, two Powered Bookshelf speakers from KEF and Q Acoustics. 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 Q Acoustics M20 HD 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 Q Acoustics M20 HD 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 and M20 HD are 2-way speakers.
| Driver |
KEF LSX II |
Q Acoustics M20 HD |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
0.75-inch
|
0.875-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 4.5-inch
|
1 x 5-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 M20 HD features a 0.875" Dome Tweeter and 1 x 5" Woofer .
Frequency Response
LSX II has a frequency range of 54-28k Hz whereas M20 HD has a frequency range of 55-22k Hz. With a minimum frequency of 54Hz, the LSX II can go slightly deeper then the M20 HD's min frequency of 55Hz.
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 M20 HD 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 Q Acoustics M20 HD's external dimensions. KEF LSX II has external dimensions of 240 × 155 × 180 mm ( 9.5 × 6.1 × 7.1 inch) whereas Q Acoustics M20 HD has external dimensions of 278.0 x 170.0 x 310.0mm ( 10-15/16 x 6-11/16 x 12-3/16inch) .
Q Acoustics M20 HD is clearly the larger of the two speakers. Its body is 15mm wider, 38mm taller and 130mm deeper than KEF LSX II.
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 Q Acoustics M20 HD is approximately 527.0cm2 / 81.7inch2. The LSX II requires 47% less surface area than the M20 HD which gives it a small advantage on placement in tight spaces.
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 Q Acoustics M20 HD weighs 5.10kg / 11.2lbs. This makes the M20 HD 42% heavier than the LSX II.
Here is a comparison of how LSX II and M20 HD'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 Q Acoustics M20 HD?
Here are the items that come with the M20 HD:
Powered speaker Passive speaker 6-feet AC power cord Remote control 2 AAA batteries 13-feet Speaker wire 59-inch Optical digital cable 2 Foam port plugs Owners Manual
 Low Frequency Response |
54 Hz
vs
55 Hz
|
Generates deeper bass |
 High Frequency Response |
28k Hz
vs
22k Hz
|
Generates higher frequency |
 App-Based Control |
Apple iOS, Android
vs
None
|
Control the speaker via an app |
 Height |
240mm
vs
278mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
279cm2 (155x180mm)
vs
527cm2 (170x310mm)
|
Takes less floor space |
 Ethernet Connection |
Yes
vs
No
|
High quality streaming over Ethernet |
 USB Port |
USB-C (connects to your computer)
vs
No
|
USB port adds flexibility |
 HDMI Input |
ARC
vs
No
|
Connect HDMI sources directly |
| Woofer Size |
5 inches
vs
4.5 inches
|
Larger woofer |
 Price per pair* |
599USD
vs
1299USD
|
costs less (*prices may change depending on the seller, location and time) |
 RCA Connection |
Yes
vs
No
|
Connection via RCA input |
| General |
KEF LSX II |
Q Acoustics M20 HD Wireless Music System |
| Brand |
KEF |
Q Acoustics |
| Speaker Type |
Powered Stereo Speakers |
Powered stereo speakers |
| Frequency Response |
54-28k Hz |
55-22k Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
200-watt RMS |
128-watt RMS |
| Max Bit Depth |
24-bit |
24-bit |
| Max Sample Rate |
384 kHz |
192 kHz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
4.5" |
5" |
| Woofer Composition |
Magnesium/Aluminium alloy |
|
| Woofer Surround Material |
Rubber |
n/a |
| Tweeter Size |
0.75" |
0.875" |
| Tweeter Type |
Hard-Dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
240.0mm (9.4") |
278.0mm (10.9") |
| Width |
155.0mm (6.1") |
170.0mm (6.7") |
| Depth |
180.0mm (7.1") |
310.0mm (12.2") |
| Weight |
3.60kg (7.9lbs) |
5.10kg (11.2lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Available Colors |
Carbon Black, Mineral White, Cobalt Blue, Lava Red, and Soundwave |
Black, White, Walnut |
| Mounting Bracket |
No |
No |
| Grille |
n/a |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Aux Inputs |
3.5mm |
3.5mm, Stereo RCA |
| USB Port |
USB-C (connects to your computer) |
USB-B |
| Phone Input |
No |
No |
| Subwoofer Output |
Wired |
mono-RCA |
| Digital Input |
Optical |
Optical |
| HDMI Input |
ARC |
No |
| Headphone Jack |
No |
No |
| Ethernet Port |
Yes |
No |
Other |
|
|
| Parts Warranty |
1 Year |
2 Years |
| Labor Warranty |
1 Year |
2 Years |