In this review, we will be comparing NX-70A and LSX, two Powered Bookshelf speakers from Yamaha and KEF. 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 Yamaha NX-70A and KEF LSX first before getting into our more
detailed comparison.
| Key Specs | Yamaha NX-70A | KEF LSX |
|---|
| Brand | Yamaha
Japan · founded 1887 | KEF
United Kingdom · founded 1961 |
|---|
| Design | 2-way | 2-way |
|---|
| Built-in amplifier | 160-watt RMS | 200-watt RMS |
|---|
| Uni-Q driver | — | 11th Generation Uni-Q |
|---|
| Tweeter | 1.25" Dome | 0.75" Hard-Dome |
|---|
| Woofer | 5.25" Harmonious Diaphragm (ZYLON and spruce) | 4.5" Magnesium/Aluminium alloy |
|---|
| Frequency response | 50-35k Hz | 59-28k Hz |
|---|
| Max depth / sample rate | — | 24-bit / 96 kHz |
|---|
| Bluetooth | Built-in | Built-in 4.2 |
|---|
| App control | Yes | Yes |
|---|
| Weight | 5.40kg / 11.9lbs | 3.50kg / 7.7lbs |
|---|
| Dimensions (H x W x D) | 13.125" x 7.5" x 9.25"
333.0 x 189.0 x 234.0mm | 9.4375" x 6.125" x 7.1"
239.7 x 155.6 x 180mm |
|---|
The sections below take each area in turn: drivers, frequency response, physical size and what you get in the box.
Drivers
Both NX-70A and LSX are 2-way speakers.
Yamaha NX-70AKEF LSX
TweeterWoofer
Front view, drawn to scale - cabinets and drivers share one scale, so sizes are directly comparable. Hover a driver for its size.
| Driver |
Yamaha NX-70A |
KEF LSX |
|
Driver Setup
|
2-way
|
2-way
|
|
Tweeter
|
1.25-inch
|
0.75-inch
|
|
Midrange
|
- |
- |
|
Woofer
|
1 x 5.25-inch
|
1 x 4.5-inch
|
NX-70A features a 1.25" Harmonious Diaphragm (ZYLON and spruce) Dome Tweeter and 1 x 5.25" Harmonious Diaphragm (ZYLON and spruce) Woofer. On the other hand, the LSX features a 0.75" Aluminum Hard-Dome Tweeter and 1 x 4.5" Magnesium/Aluminium alloy Woofer.
Frequency Response
NX-70A has a frequency range of 50-35k Hz whereas LSX has a frequency range of 59-28k Hz. With a minimum frequency of 50Hz, the NX-70A can go significantly deeper on the low side and provide stronger bass compared to the LSX's min frequency of 59Hz.
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 NX-70A and LSX 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
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 Yamaha NX-70A's and KEF LSX's external dimensions. Yamaha NX-70A has external dimensions of 333.0 x 189.0 x 234.0mm (13.125 x 7.5 x 9.25inch) whereas KEF LSX has external dimensions of 239.7 x 155.6 x 180mm (9.4375 x 6.125 x 7.1inch).
Yamaha NX-70A is clearly the larger of the two speakers. Its body is 33.4mm wider, 93.3mm taller and 54mm deeper than KEF LSX.
Size, drawn to scale
Both speakers and both views share one scale, so everything here is directly comparable. Hover a box for its dimensions.
One scale for both, standing on the same surface and pushed back to the same wall, so the deeper one visibly sticks out further.
Yamaha NX-70A needs about 58% more floor or shelf area. Yamaha NX-70A is 54mm deeper, so it stands that much further out from the wall. Yamaha NX-70A is 93mm taller.
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 Yamaha NX-70A is approximately 442.3cm2 / 68.6inch2 and base area of the KEF LSX is approximately 280.1cm2 / 43.4inch2. The NX-70A requires 58% more surface area than the LSX which gives it a small disadvantage 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 Yamaha NX-70A weighs 5.40kg / 11.9lbs and the KEF LSX weighs 3.50kg / 7.7lbs. This makes the NX-70A 54% heavier than the LSX.
Here is a comparison of how NX-70A and LSX's weights compare with the average, max and min weights in Powered Bookshelf class.
Weight
All Bookshelf Speakers
What's in the Box of Yamaha NX-70A?
Here are the items that are included inside the box of NX-70A:
- Remote control
- 2 AAA batteries
- 2 x 2m power cables
- 2m HDMI cable
- 3m LAN cable for the wired L/R connection
- 6m YPAO microphone
- Cardboard microphone stand
- Quick guide
- Safety guide
What's in the Box of KEF LSX?
Here are the items that come with the LSX:
- 2 Powered wireless audio speaker
- Two 6.5-feet AC power cords
- 10-feet Ethernet cable
- Remote control (CR2032 3V battery pre-installed)
- Maintenance Guide
- Specifications
- Warranty Information
- Important Safety Information
 Woofer Size |
5.25 inches
vs
4.5 inches
|
Larger woofer |
|
Low Frequency Response |
50 Hz
vs
59 Hz
|
Generates deeper bass |
 High Frequency Response |
35k Hz
vs
28k Hz
|
Generates higher frequency |
 HDMI Input |
eARC
vs
No
|
Connect HDMI sources directly |
 Height |
239mm
vs
333mm
|
Easier to fit in smaller spaces |
 Base Surface Area |
280cm2
vs
442cm2
|
Takes less floor space |
 Price per pair* |
1250USD
vs
3000USD
|
costs less (*prices may change depending on the seller, location and time) |
| General |
Yamaha NX-70A |
KEF LSX |
| Brand |
Yamaha |
KEF |
| Speaker Type |
Powered Stereo Speakers |
Powered Stereo Speakers |
| Frequency Response |
50-35k Hz |
59-28k Hz |
Amplifier |
|
|
| Watts RMS (Continuous) |
160-watt RMS |
200-watt RMS |
| Max Bit Depth |
n/a |
24-bit |
| Max Sample Rate |
n/a |
96 kHz |
Drivers |
|
|
| Woofer Quantity |
1 |
1 |
| Woofer Size |
5.25" |
4.5" |
| Woofer Composition |
Harmonious Diaphragm (ZYLON and spruce) |
Magnesium/Aluminium alloy |
| Woofer Surround Material |
n/a |
Rubber |
| Tweeter Size |
1.25" |
0.75" |
| Tweeter Type |
Dome |
Hard-Dome |
| Aimable Tweeter |
No |
No |
| Midrange Driver |
No |
No |
| Firing Direction |
rear |
rear |
Physical Specs |
|
|
| Height |
333.0mm (13.1") |
239.7mm (9.4") |
| Width |
189.0mm (7.4") |
155.6mm (6.1") |
| Depth |
234.0mm (9.2") |
180.0mm (7.1") |
| Weight |
5.40kg (11.9lbs) |
3.50kg (7.7lbs) |
| Enclosure |
Bass Reflex |
Bass Reflex |
| Available Colors |
n/a |
Black, Olive Green, Gloss White |
| Mounting Bracket |
|
No |
| Moisture Resistancy |
No |
No |
Connections |
|
|
| Aux Inputs |
3.5mm |
3.5mm |
| USB Port |
n/a |
Charge only |
| Phone Input |
No |
No |
| Subwoofer Output |
mono-RCA |
Wired |
| Digital Input |
1 |
Optical |
| HDMI Input |
eARC |
No |
| Headphone Jack |
No |
No |
| Ethernet Port |
Yes |
Yes |
Other |
|
|
| Parts Warranty |
|
1 Year |
| Labor Warranty |
|
1 Year |
These sit in different price classes - Yamaha NX-70A costs roughly 2.4x what KEF LSX 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 | A | Yamaha NX-70A digs deeper - 50Hz against 59Hz. A subwoofer would even that out. |
| Built-in power | B | KEF LSX has the bigger amplifier (200W vs 160W RMS). |
| Connections | A | Yamaha NX-70A adds HDMI. |
| Size | depends | KEF LSX is easier to place; Yamaha NX-70A is bigger, which usually goes with fuller bass. Your room decides. |
| Expandability | depends | Yamaha NX-70A: a sub output; KEF LSX: a sub output. KEF LSX sits in a wider range (10 models), so a matched surround system is easier later. |
| Price | B | KEF LSX is cheaper - $1,250 against $3,000, about 58% less; arguably a different class. |
A Yamaha NX-70A B KEF LSX
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?
Yamaha NX-70A is ahead, but only on 1 of the measured areas, and it costs about 140% more. That is a lot of money for a narrow margin on paper - KEF LSX looks like the sensible buy unless something else about the Yamaha NX-70A appeals to you. If a subwoofer is in your plans, the bass gap largely stops mattering - you would be crossing over above 59Hz anyway, which makes the cheaper KEF LSX much easier to justify. In a large or open-plan room, Yamaha NX-70A has the cabinet volume to fill it more easily; in a small room, near a wall or at desk distance, KEF LSX is the easier speaker to get right.
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.