In this review, we will be comparing LSX II and Prime Wireless, two Powered Bookshelf speakers from KEF and SVS. 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 SVS Prime Wireless first before getting into our more
detailed comparison.
| Key Specs | KEF LSX II | SVS Prime Wireless |
|---|
| Brand | KEF
United Kingdom · founded 1961 | SVS
United States · founded 1998 |
|---|
| Design | 2-way | 2-way |
|---|
| Built-in amplifier | 200-watt RMS | 200-watt RMS |
|---|
| Uni-Q driver | 11th Generation Uni-Q | — |
|---|
| Tweeter | 0.75" Hard-Dome | 1" Dome |
|---|
| Woofer | 4.5" Magnesium/Aluminium alloy | 4.5" composite glass-fiber |
|---|
| Frequency response | 54-28k Hz | 52-25k Hz |
|---|
| Max depth / sample rate | 24-bit / 384 kHz | 24-bit / 192 kHz |
|---|
| Bluetooth | Built-in 4.2 | Built-in 4.0 |
|---|
| App control | Yes | Yes |
|---|
| Weight | 3.60kg / 7.9lbs | 3.96kg / 8.7lbs |
|---|
| Dimensions (H x W x D) | 9.5" x 6.1" x 7.1"
240 × 155 × 180 mm | 10.3125" x 6.125" x 8.6875"
260 x 155 x 220.7 mm |
|---|
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
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Drivers
Both LSX II and Prime Wireless are 2-way speakers.
KEF LSX IISVS Prime Wireless
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
KEF LSX II |
SVS Prime Wireless |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
0.75-inch
|
1-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 4.5-inch
|
1 x 4.5-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 Prime Wireless features a 1" aluminum Dome Tweeter and 1 x 4.5" composite glass-fiber Woofer with a Crossover frequency at 2000Hz.
Frequency Response
LSX II has a frequency range of 54-28k Hz whereas Prime Wireless has a frequency range of 52-25k Hz. With a minimum frequency of 52Hz, the Prime Wireless can go slightly deeper then the LSX II's min frequency of 54Hz.
The graph below depicts how these two speakers compare with the max, min and average Low Frequency values of other speakers in the Bookshelf class in our database.
Low Frequency
Bookshelf Speakers
Neither pair reaches down to 20Hz, the usual definition of full-range, which is normal for speakers of this size. If you want the bottom octave for movies or bass-heavy music, add a subwoofer to whichever you choose. Visit our Powered Subwoofers section to find out more about the available options.
Cabinet Type and Port Position
Both LSX II and Prime Wireless 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
The size of a speaker can sometimes be 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 SVS Prime Wireless's external dimensions. KEF LSX II has external dimensions of 240 × 155 × 180 mm (9.5 × 6.1 × 7.1 inch) whereas SVS Prime Wireless has external dimensions of 260 x 155 x 220.7 mm (10.3125 x 6.125 x 8.6875 inch).
Below you can see the front view size comparison of KEF LSX II and SVS Prime Wireless in scale.
Comparison image of KEF LSX II and SVS Prime Wireless 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 SVS Prime Wireless is approximately 342.1cm2 / 53.0inch2. The LSX II requires 18% less surface area than the Prime Wireless which gives it a small advantage on placement in tight spaces.
Here is 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 SVS Prime Wireless 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 SVS Prime Wireless weighs 3.96kg / 8.7lbs. This makes the Prime Wireless 10% heavier than the LSX II.
Here is a comparison of how LSX II and Prime Wireless'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 speakers
- Two 6.5-feet AC power cords
- 10-feet Cat-6 interconnect speaker cable
- Remote control
- 2 AAA batteries
- Quick Start Guide
- Important Safety Information
- Warranty Information
- Maintenance Guide
What's in the Box of SVS Prime Wireless?
Here are the items that come with the Prime Wireless:
- Active wireless speaker
- 6-feet AC power cord
- Grille (pre-installed)
- 4 Self-adhesive feet
- Quick Start Guide
- Warranty/Registration Card
- SVS brochure
 High Frequency Response |
28k Hz
vs
25k Hz
|
Generates higher frequency |
 Handheld Remote |
Yes
vs
No
|
Control the speaker by the included RC |
 Height |
240mm
vs
260mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
279cm2
vs
342cm2
|
Takes less floor space |
 HDMI Input |
ARC
vs
No
|
Connect HDMI sources directly |
 Low Frequency Response |
52 Hz
vs
54 Hz
|
Generates deeper bass |
 Price per pair* |
449USD
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 |
SVS Prime Wireless |
| Brand |
KEF |
SVS |
| Speaker Type |
Powered Stereo Speakers |
Powered Stereo Speakers |
| Frequency Response |
54-28k Hz |
52-25k Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
200-watt RMS |
200-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" |
4.5" |
| Woofer Composition |
Magnesium/Aluminium alloy |
composite glass-fiber |
| Woofer Surround Material |
Rubber |
n/a |
| Tweeter Size |
0.75" |
1" |
| Tweeter Type |
Hard-Dome |
Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Crossover Frequency |
n/a |
2000Hz |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
240.0mm (9.4") |
260.0mm (10.2") |
| Width |
155.0mm (6.1") |
155.0mm (6.1") |
| Depth |
180.0mm (7.1") |
220.7mm (8.7") |
| Weight |
3.60kg (7.9lbs) |
3.96kg (8.7lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Available Colors |
Carbon Black, Mineral White, Cobalt Blue, Lava Red, and Soundwave |
Black |
| Mounting Bracket |
No |
No |
| Grille |
n/a |
Yes |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Aux Inputs |
3.5mm |
3.5mm, RCA |
| USB Port |
USB-C (connects to your computer) |
Service only |
| Phone Input |
No |
No |
| Subwoofer Output |
Wired |
Wired |
| Digital Input |
Optical |
Optical |
| HDMI Input |
ARC |
No |
| Headphone Jack |
No |
No |
| Ethernet Port |
Yes |
Yes |
Other |
|
|
| Parts Warranty |
1 Year |
2 Years |
| Labor Warranty |
1 Year |
2 Years |
These sit in different price classes - KEF LSX II costs roughly 2.9x what SVS Prime Wireless does. Expect it to lead on paper; the question is whether the gap is audible enough in your room to be worth it.
| Area | Better | Why |
|---|
| Bass | evenly matched | Much the same reach (54Hz vs 52Hz). |
| Built-in power | evenly matched | Similar onboard amplification (200W vs 200W RMS). |
| Connections | A | KEF LSX II adds HDMI. |
| Size | depends | KEF LSX II is easier to place; SVS Prime Wireless is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | depends | KEF LSX II: a sub output; SVS Prime Wireless: a sub output. |
| Price | B | SVS Prime Wireless is cheaper - $449 against $1,299, about 65% less; arguably a different class. |
A KEF LSX II B SVS Prime Wireless
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both speakers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
KEF LSX II is ahead, but only on 1 of the measured areas, and it costs about 2.9x the price. That is a lot of money for a narrow margin on paper - SVS Prime Wireless looks like the sensible buy unless something else about the KEF LSX II appeals to you. Think about the whole system, not just the speakers: the roughly $850 saved by taking the cheaper pair would buy a subwoofer or a better amplifier, and either usually does more for the sound than the difference between these two.
And remember what a spec sheet cannot show: how each looks in your room and whether the finish suits it, what dealer support and warranty are like where you live, and how they actually sound to you. If you can hear them first - ideally with your own music - that will tell you more than any number above.